STS-134:

Originally, the plan was to end the Space Shuttle Program (SSP) with the STS-133 flight. Indeed, the last two planned missions – STS-132 and STS-133 – began life on the Flight Assignments Working Group (FAWG) manifests (full set from STS-1 onwards in L2) as CLF (Contingency Logistics Flight) missions, prior to what became a mini-extension of the Shuttle fleet’s swansong.

STS-134 came to life via the Flight Definition and Requirements Directive (FDRD) process as a mission for Discovery, based on strong political support to extend the life of the International Space Station (ISS), and to facilitate a ride uphill for AMS-02.

Initially, funding for STS-134 had yet to be secured. However, MOD teams were able to begin their traditional “Plan/Train/Fly – PTF” approach to the mission, via the support of a NASA Authorization Bill in September of 2008, which directed NASA to “take all necessary steps” to add STS-134′s delivery of AMS to the Station into the schedule.

The mission was still lacking certainty, not least because the Bill contains a caveat for the NASA Administrator to cancel the flight, within one year ahead of its launch, if it was determined that it could cost significantly more than the existing estimate, or that it would create an unacceptable safety risk.

Had NASA’s leadership taken such a route, Congress would have had to reauthorize the flight, or the President would have had to certify that it is in the national interest to fly the mission.

Thankfully, STS-134 soon matured into a baselined mission – as seen in its progression on the FAWG manifests – as it moved from a Launch On Need (LON) support mission, to an actual mission in its own right.

With a Change Request (CR) swapping the STS-134 mission from Discovery to Endeavour, the youngest orbiter in the fleet was baselined to carry to the Alpha Magnetic Spectrometer 2 (AMS-02), Express Logistics Carrier 3 (ELC-3), Materials on International Space Station Experiment 8 (MISSE 8), an Orion Rendezvous Detailed Test Objective (DTO) kit, and a GLACIER freezer module for one of the Station’s science laboratories.

Click here for the full range of STS-134 News Articles: http://www.nasaspaceflight.com/tag/sts-134/

Endeavour would also return the MISSE 7a and 7b experiments to Earth as well as perform four Department of Defense payloads of opportunity: MAUI, SEITI, RAMBO-2, and SIMPLEX.

The STS-134 FDRD document (available in L2) provided an overview of Endeavour’s final – and rather large payload – up-mass, totaling 36,740lbs, including middeck payload and crew equipment weight.

The star of the show as the primary payload was AMS-02 – weighing 15,300lbs.

Tagged as a “particle physics detector”, designed with a large, cryogenic super-fluid helium superconducting magnet, the AMS-02 unit was constructed to “search for antimatter and the origin and structure of dark matter.”

Ironically, it was that magnet that became a problem ahead of the launch date – relating to a vastly reduced lifetime estimation that was observed during testing in Holland, as engineers worked on finding a solution that would allow AMS to enjoy a lifetime that would match the extension of ISS operations until at least 2020.

A decision to changeout the hardware for a permanent magnet, as noted by the STS-134 Mission Integration Manager (MIM) at the time, which in turn slipped the launch date deeper into 2011.

Getting AMS-02 uphill to the ISS was also a challenge, with mission documentation (L2) noting the need for four longeron payload latches and one active keel latch for its attachment to the payload bay sidewalls of Endeavour.

Additionally, once on orbit, Remotely Operated Electrical Umbilicals (ROEU) would provide AMS-02 with 124V of power for its heaters and avionics – required to keep it alive in the cold of space.

Prior to liftoff, this power was provided via the T-0 umbilicals on the launch pad. These T-0 umbilicals also allowed launch personnel to monitor the health of AMS-02 prior to liftoff and make sure that Launch Commit Criteria for the AMS-02 was not breached.

Endeavour had an eventful final flow at the launch pad, with her first launch attempt scrubbed due to problems with heaters on her Auxiliary Power Units (APUs).

Launching on May 16, 2011 – Endeaovur enjoyed a successful trip to the ISS, kicking off the docked phase with the transition of AMS-02 from the orbiter’s payload bay to its new home on the Station.

The robotic ballet involved the Shuttle Remote Manipulator System (SRMS) unberthing the AMS from the payload bay, before handing AMS to the SSRMS (Space Station Remote Manipulator System).

The crew then ungrappled the SRMS from AMS, officially handing the experiment over to the ISS, before it was maneuvered to its attachment point on the Starboard 3 Upper Inboard Command Attach System (CAS).

This was followed by stage one installation/first stage capture. Stage two installation was completed, before the umbilical mates were then secured. The SSRMS then ungrappled AMS, marking the completion of its permanent installation on ISS.

Endeavour completed her final mission and returned home on June 1, 2011.

(Animated image resized from hires/full screen version and sequence photo dumps on L2′s STS-134 Flight Day image section - several hundred megabytes strong – L2 Link.) 

She was then placed into a Transition & Retirement (T&R) flow – marked by her final powerdown in May, 2012. 

Endeavour was then given an emotional farewell tour on the back of the Shuttle Carrier Aircraft, prior to her handover to her retirement home at the California Science Center (CSC).

However, her final primary payload lives on, with Wednesday’s announcement of AMS-02′s first set of results on the ISS causing interest from around the world.

The results noted that since its installation, AMS-02 has measured over 30 billion cosmic rays at energies up to trillions of electron volts.

Its permanent magnet and array of precision particle detectors collect and identify charged cosmic rays passing through AMS from the far reaches of space. Over its long duration mission on the ISS, AMS will record signals from 16 billion cosmic rays every year and transmit them to Earth for analysis by the AMS Collaboration.

Importantly, the results note that AMS-02 has seen evidence of what may be proven to be the elusive “dark matter” – the mysterious element that accounts for most of the mass in the Universe – colliding with itself.

“The AMS cosmic ray particle results announced today could help foster a new understanding of the fields of fundamental physics and astrophysics,” noted NASA administrator Charlie Bolden. “I am confident that this is only the first of many scientific discoveries enabled by the station that will change our understanding of the universe.

“Multiple NASA human spaceflight centers around the country played important roles in this work, and we look forward to many more exciting results from AMS.”

A lot more work and research will be required to advance the findings, but the value of the AMS-02 is now becoming more obvious – all made possible by some political will, some clever scientists, the orbital outpost that is the ISS, and the capable baby of the Shuttle fleet, Endeavour.

(Images: Via NASA and L2 content from L2′s Expansive STS-134 specific section, which includes vast amount of FRR/PRCB level presentations, photos, graphics, videos, flow and mission updates – compelte coverage available on no other site.)

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Endeavour back home in OPF-2; final KSC work begins on the baby orbiter:

Since being relegated to VAB (Vehicle Assembly Building) HB-4 (High Bay 4) in August 2011 to allow sister Discovery access to OPF-1 to complete her retirement and decommissioning flow, Space Shuttle orbiter Endeavour has sat in the VAB to be viewed by spectators and visitors to the Kennedy Space Center – a role she will soon adopt full-time later this year.

After nearly six months in the VAB – a stay in storage longer then numerous of her OPF processing flows for her 25 flights – Endeavour’s engineers flocked to her side this morning for final preparations for her move back to her home in OPF-2.

With Endeavour (OV-105) safely cocooned inside the protective and processing structures of OPF-2, final decommission work will now proceed on the baby of NASA’s Shuttle fleet.

Serving her country and the world space community proud for just one-fourth of her total design life, Endeavour will now spend the next six months (at least) inside OPF-2 – the OPF that became her very own processing facility in 2003, following the tragic loss of her sister Columbia (OV-102) and her valiant international crew of seven men and women – the 9 year anniversary of which we remember today.

After vacating OPF-2 on 28 February 2011 for mating with her ET and SRB stack for her final voyage, Endeavour was taken into OPF-1 on 1 June 2011, following her successful return from the STS-134 mission.

In OPF-1, Endeavour was quickly deserviced from STS-134 flight status before being taken into full-up decommissioning operations – which saw her lose her three SSMEs (Space Shuttle Main Engines), OMS pods, FRCS (Forward Reaction Control System) pod, SRMS (Shuttle Remote Manipulator System) arm, and numerous pieces of internal equipment.

Stripped down and exposed, Endeavour was rolled out of OPF-1 on 11 August 2011 to make room for sister Discovery.

Since then, Endeavour has been stored in the VAB, with no work being performed on her during her stay in the VAB.

Following the removal of Space Shuttle orbiter Atlantis (OV-104) from OPF-2 on Friday, 20 January 2012 to make room for Endeavour, technicians in Endeavour’s home OPF have been busy performing Open Bay Work – scheduled maintenance and upkeep work on the OPF-2 systems that cannot be undertaken with a Shuttle orbiter present in the bay.

With that standard Open Bay Work complete, Endeavour will now take center stage in the OPF as technicians complete all open work for her eventual centerpiece display at the California Science Center in Los Angeles, California.

In addition to the installation of three Replica Shuttle Main Engines (RSMEs) into her aft, Endeavour will also receive her now-cosmetic-only OMS Pods and FRCS pod before having portions of her MPS (Main Propulsion System) removed for the SLS rocket and related program.

Significant work will also be conducted in the space underneath her Payload Bay as final efforts to completely safe Endeavour for public display are carried out.

Endeavour, however, will not receive her SRMS arm back. That arm, which enabled many of her accomplishments throughout her life, will be given to a Canadian museum – still to be determined – in acknowledgement of and thanks for Canada’s support for the Shuttle Program since its conception in the 1970s.

Like Discovery before her, Endeavour’s payload bay doors will then be closed for the final time and power cut to historic vehicle for the final time.

With power already terminated to former fleet leader Discovery and middle child Atlantis, Endeavour – despite having flown the penultimate flight of the Shuttle Program – will be the final surviving Shuttle orbiter once hooked back up to OPF power this week.

The most recent information indicates the Endeavour will be powered through mid-March, though with all T&R (Transition and Retirement) flow schedules in flux and under a certain degree of pressure to be finished quickly, it’s possible Endeavour could be powered down for the final time earlier than mid-March.

Click here for T&R Articles: http://www.nasaspaceflight.com/tag/T&R/

After this milestone is passed, she will then be fitted with a tailcone assembly to prepare her for her ferry flight across the country to the CSC.

While timelines are currently in flux because of the added work of having to remove MPS components from all three orbiters – work that has not yet begun on Endeavour or her sister Atlantis, KSC Orbiter T&R Manager Stephanie Stilson revealed in an interview with NASASpaceflight.com’s Philip Sloss that KSC is currently targeting a mid-September, 2012 ferry flight for Endeavour, as much as this has since slipped to the October timeframe.

The double switch - Atlantis to take Endeavour place in VAB HB4:

With Endeavour safely in her OPF, Shuttle orbiter Atlantis (OV-104) has now taken up residence in VAB HB4, which involved her being wheeled out of the VAB transfer aisle and around the side of the building to the HB4 entrance – a move which was delayed until next week, before being pushed back up to Thursday and completed in the afternoon.

This now become Atlantis’s temporary home for February and most of March while her big sister Discovery completes her final KSC processing milestones in OPF-1.

However, Atlantis’s stay in the VAB will not be as solitary as Endeavour’s proved.

Unlike Endeavour, which saw now work performed on her during her VAB vacation, Atlantis will undergo the beginnings of her MPS tear down and removal while in the VAB.

While timelines are not solidified yet based on ongoing MPS tear down and removal work on Discovery in OPF-1, Atlantis is expected to remain in VAB HB4 until mid- to late-March 2012.

At this time, once all work is terminated on Discovery, the veteran flyer will be removed from OPF-1 and rolled over to the VAB for her last few weeks at her Kennedy home – a place she has called home since 1983.

After OPF-1 is vacated, Atlantis will be wheeled into the processing facility for her final T&R work.

In mid-April, Discovery will be rolled on her wheels from the VAB, past her two sisters, and out to Shuttle Landing Facility where she will be picked up by the Mate-Demate Device and her wheels retracted up into her belly.

Discovery will then be mated to the Shuttle Carrier Aircraft and flown up the eastern seaboard of the United States to Washington, D.C. and the Smithsonian’s National Air and Space Museum on April 17, 2012 – 31 years 5 days after Columbia roared off Launch Pad 39A to begin this historic program.

To read about the orbiters -  from birth, processing, every single mission, through to retirement, click here for the links:
http://forum.nasaspaceflight.com/index.php?topic=25837.0

(Images: Via NASA and L2 content – And special photography provided by Philip Sloss, NASASpaceflight.com and Larry Sullivan, MaxQ/NASASpaceflight.com – many thousands of super hi-res image stock available on L2′s new Photo Section)

(L2 and NSF are continuing to follow the orbiters through their transitional period. To join L2, click here: http://www.nasaspaceflight.com/l2/)

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SSMEs Shipping Out:

The change of home from the Kennedy Space Center (KSC) to NASA’s Stennis Space Center (SSC) in south Mississippi is a natural transition for the 15 engines, not least because the SSMEs underwent testing at Stennis ahead of their flight roles with the orbiters.

However, it’s their future role of becoming part of the SLS test program which has breathed new life into the famous engines, some of which will actually gain the honor of going out in style, launching one last time with the SLS during the first few missions.

Their transition from KSC will take place one engine at a time, as they travel to Mississippi by truck. Once at SSC, the SSMEs will join SLS’ Upper Stage J-2X engine – which is being tested at the facility – allowing for all SLS engine assets to be in one location, leveraging the existing knowledge base, skills, infrastructure and personnel.

“The relocation of RS-25D engine assets represents a significant cost savings to the SLS Program by consolidating SLS engine assembly and test operations at a single facility,” said William Gerstenmaier, NASA’s associate administrator for Human Exploration and Operations Mission Directorate.

The relocation also frees up the Space Shuttle Main Engine Processing Facility at KSC, which became part of a commercial deal with Boeing – in collaboration with NASA and Space Florida – to being exclusively occupied  by the company, along with Orbiter Processing Facility 3 (OPF-3) and the Processing Control Center, as they ramp up operations for their CST-100 spacecraft.

“This enables the sharing of personnel, resources and practices across all engine projects, allows flexibility and responsiveness to the SLS program, and it is more affordable,” said Johnny Heflin, RS-25D core stage engine lead in the SLS Liquid Engines Office at Marshall.

“It also frees up the space, allowing Kennedy to move forward relative to commercial customers.”

SSME: End Of A Shuttle Era:

The RS-25s have an amazing flight record with the Space Shuttle – with only one engine suffering a problem during the entire 30 years of the program.

*To read about all three orbiters - from birth, processing, every single mission, through to retirement - click here for the links:
http://forum.nasaspaceflight.com/index.php?topic=25837.0*

That single issue occurred during STS-51F with Challenger, when one of two high pressure fuel turbopump turbine discharge temperature sensors for SSME-1 failed, leaving only one sensor active on the engine. Two minutes 12 seconds later, at Mission Elapsed Time 5mins 43secs, the second sensor failed, triggering the immediate shutdown of SSME-1.

The shutdown of SSME-1 significantly lowered the thrust profile for Challenger and triggered the only in-flight abort in Shuttle Program history: an Abort To Orbit (ATO) which allowed Challenger and her seven-member crew to reach a lower-than-planned but safe and stable orbit.

Nonetheless, before Challenger could complete her prolonged ascent (nearly 9mins 45secs in duration due to the lost thrust from SSME-1), an identical high pressure turbopump temperature sensor failure occurred in SSME-2.

Booster Systems Engineer Jenny M. Howard in Mission Control Houston acted immediately, instructing the crew to inhibit any further automatic SSME shutdowns based on readings from the remaining sensors. This quick action prevented the loss of another engine and a possible abort scenario far more risky or far worse than the already in-progress ATO.

When Challenger finally reached orbit, several aspects of the mission were retooled to account for the lower-than-planned orbital altitude.

Click here to read recent articles on the SSMEs: http://www.nasaspaceflight.com/tag/ssme/

As per the In Flight Anomaly (IFA) reports for the final three missions, all nine of the SSMEs performed admirably, as they assisted the orbiters for the ride uphill into orbit.

For STS-133, all three of Discovery’s SSMEs last flew with Atlantis during STS-129, although in different positions – after they required removing and re-installing in different positions, in order to allow a changeout of ME-1′s Low Pressure Oxidizer Turbo Pump (LPOTP) early in the flow.

Discovery flew with Main Engine 1 (ME-1) – serial number 2044, ME-2 – 2048 and ME-3 – 2058. All their related hardware was the same as that which flew with Atlantis, bar a couple of elements, such as a new nozzle for ME-1.

The only notable issue with the SSMEs occurred pre-launch, relating to a power issue with the redundant Main Engine Controller (MEC) on SSME 3.

The SSME controllers provides complete and continuous monitoring and control of engine operation. In addition, it performs maintenance and start preparation checks, and collects data for historical and maintenance purposes.

STS-133 Specific – Including ET Stringer Issue – Articles: http://www.nasaspaceflight.com/tag/sts-133/

The controller is an electronic package that contains five major sections; power supply section, input electronics section, output electronics sections, computer interface section, and digital computer unit.

Pressure, temperature, pump speed, flowrate, and position sensors supply the input signals. Output signals operate spark igniters, solenoid valves, and hydraulic actuators. The controller is dual redundant, which gives it normal, fail-operate, and fail-safe operational mode capability. The problem was specific to the redundant controller on ME-3.

Actions taken during troubleshooting included the installation of a breakout box and the testing of three single phase circuit breakers for SSMEC 3B on Panel L4. Although this inspection was limited by access, engineers pro-actively replaced all 18 SSMEC circuit breakers at the recommendation of management.

The problem soon became clear when CB 109 was inspected, with a clear observation of non-conductive debris on the hardware, a key candidate for the original problem seen with SSME 3′s redundant MEC.

After the troubleshooting was signed off at the Flight Readiness Review (FRR), all three engines – and controllers – performed without issue during ascent.

“Engine operation was nominal. ME-1 2044, ME-2 2048, ME-3 2058 – No SSME IFA Identified,” noted the STS-133 SSME IFA presentation (L2 Link to Presentation). “SSME observations are encompassed by previous flight and/or test experience and identified as no impact.

For STS-134, Endeavour’s ride into orbit was aided by a noisy trio that were no stranger to the aft of the youngest orbiter in the fleet, after pushing her uphill during STS-130.

The engines were installed for one final trip with Endeavour in the following positions on the orbiter: ME-1 – 2059, ME-2 – 2061, while 2057 was ME-3.

Only one item of interest made it into the FRR documentation for the SSMEs ahead of STS-134′s mission, referencing the incident when an ELSA (Life Support) bottle fell from the entrance level near the 50-2 door and hit Main Engine 2 (ME-2) during Vehicle Assembly Building (VAB) processing operations.

“STS-134 Endeavour ME 2 ELSA Bottle Damage Inspections: Issue: Possible handling damage to ME-2. Background: ELSA Bottle dropped from above ME-2 to heat shield adjacent to controller during VAB processing. Damage observed above and adjacent to engine,” noted the STS-134 SSME SSP FRR presentation (L2 Link to Presentation).

“Dent in Orbiter GN2 Line. Dent on edge of Heat Shield near ME-2 controller. Witness statements and damage indicate no engine impact. Assessment conducted around 4.5 Ft assuming possible engine contact.”

With this issue cleared, Endeavour launched on her final mission without incident and successfully completed her mission on June 1, 2011.

As what became a regular observation, the 14-15 IFA presentations per mission (all acquired by L2 –  link to presentation collection) reviewing the mission post flight included a very short SSME presentation, noting no anomalies (L2 Link to Presentation).

STS-134 Specific Articles: http://www.nasaspaceflight.com/tag/sts-134/

For STS-135, Atlantis’ engines were ME-1 – 2047, ME-2 – 2060 and ME-3 – 2045.

Again, the only incident of note came before the engines were fired up at launch, when IPR-49 (Interim Problem Report) noted a problem with the Main Fuel Valve (MFV) on SSME-3, spotted during a tanking test to check the integrity of the modified stringers on the stack’s External Tank (ET-138).

The MFV is a ball valve with a 2.5-inch tubular flow passage and is flange-mounted between the high pressure fuel duct and nozzle diffuser. The valve controls the flow of fuel from the HPFTP (High Pressure Fuel Turbopump) to the coolant circuits and preburners.

The issue – the observation of a leak – was also covered in depth via the STS-135 SSP Flight Readiness Review (FRR) presentation for the SSMEs (L2 Link to Presentation), which covered how the issue was spotted during the Tanking Test, as it breached the Launch Commit Criteria (LCC) limitations.

As a result, the issue would have scrubbed the launch day countdown, showing a bonus side-effect of finding the problem during the Tanking Test.

“Issue: STS-135, ME-3 (2045) Main Fuel Valve (MFV) skin temperatures indicated a MFV leak during the early stages of STS-135 tanking test. Temps violated minimum limit (LCC SSME-02). Tanking test continued with engines isolated from the fuel supply,” noted the FRR presentation.

The reference to the skin temperatures related to sensors mounted to the outside wall of the downstream duct of the MFV to detect leakage during chill. Low temperatures are indicative of a MFV leak. The LCC limits are based on the vast flight experience of the Shuttle Program.

The MFV was replaced out at the pad and put through a series of leak checks. While those passed, the real test came during launch day, when the system was put through the cryogenic environment of tanking. Again, the skilled KSC and SSME engineers were shown to have successfully fixed the problem, as Atlantis launched for the final time without issue.

STS-135 Specific Articles: http://www.nasaspaceflight.com/tag/sts-135/

Now these stalwart engines – which includes the spare flight set: ME-1 – 2052 ME-2 – 2051 and ME-3 – 2054 – plus three others, are departing KSC once again – this time by road.

SSME To SLS Core:

Their potential role with the SLS was noted during the final flights of the Shuttle, as the 2010 Authorization Act reversed the FY2011 budget proposal which would not have seen any involvement of the RS-25s.

With a Shuttle Derived (SD) version of the Heavy Lift Launch Vehicle (HLV) consistently winning during trade studies, which once again pointed at a configuration which used RS-25s as the preference, the Program Requirements Control Board (PRCB) took action to protect the engines.

While NASA’s “White House-aligned” leadership continued to avoid pressing forward with the confirmation of the SD HLV SLS configuration, the PRCB stepped in to “preserve the SSME flight engines for future Agency use” (L2 Link to Presentation)- adding to a previous action to slow down the Transition and Retirement (T&R) of the contractor ability to manufacture flight spares for the RS-25s.

The PRCB also provided the approval for the orbiters to gain Replica Shuttle Main Engines (RSMEs) – previously scrapped nozzles installed via an adaptor – for when the vehicles retire to exhibitions, freeing up the flight flown SSMEs.

For SLS/HLV Articles, click here: http://www.nasaspaceflight.com/tag/hlv/

With the orbiters also donating large elements of their Main Propulsion System (MPS) – a heavily related collection of plumbing and lines – to the SLS program, a large amount of the HLV’s core guts will be from the orbiters for at least the testing/pathfinder stage, through to the opening launches.

The ongoing trades taking place at the Marshall Space Flight Center (MSFC) are also working through the core’s configuration for the three versions of the SLS, namely the Block I – 70mt, the Block IA – 100mt, and the Block II – 130mt vehicles.

Technically, SLS could launch with three, four or five RS-25s from the outset. However, with three engines on the core, and the automatic need for the core to be “stretched” – based on the five segment boosters on the configuration – using four engines would allow the vehicle to fly fully fueled in all configurations, saving the extra calculations/testing for an under-filled three engine core.

Per the meetings – as much as no decision has been made at this time ahead of the key Systems Requirements Review (SRR) and Systems Design Review (SDR) – it appears four engines on the first stage would be best prescribed for the SLS from the start, per sources.

SLS will naturally evolve after the opening flights of the Block I SLS, with SSME contractor Pratt & Whitney Rocketdyne (PWR) producing RS-25E engines for the rest of the SLS’ lifetime. The RS-25E – based on the reusable SSME (RS-25D) – is expendable and thus requires less long-life hardware items, in turn making it cheaper to produce.
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OV-103/Discovery – The final voyage of the veteran workhorse:

For the final year of the Space Shuttle Program, operations in 2011 began where all Shuttle missions have: in the Vehicle Assembly Building.

After enduring a rollback from LC-39A in late-December 2010, because of cracks on the stringers of her External Tank’s (ET) intertank structure, Space Shuttle orbiter Discovery, OV-103, spent the first month of 2011 in the VAB undergoing ET intertank repairs and strengthening activities while the various NASA centers conducted numerous simulations to nail down the cause of the ET stringer cracks. (L2 Link).

Discovery, the third operational Shuttle orbiter and fourth overall Shuttle orbiter constructed by NASA, was preparing for her 39th and final mission in November 2010 when the stringer crack issue presented itself during the mission’s first launch attempt on November 5, 2010.

Following the discovery of this issue, NASA mission managers refused to set a launch date for the flight in a concerted effort to allow the engineering analysis teams to have the time they needed to properly and safely address the issue without feeling a push toward launch fever. 

STS-133 Specific - Including ET Stringer Issue - Articles: http://www.nasaspaceflight.com/tag/sts-133/

On January 4, NASA identified the potential root cause for the stringer issue – a mottling on the stringers themselves.

As noted by an investigation report, “Some material used for the stringers was found to be ‘mottled,’ with a different surface appearance than the standard material. Testing revealed this mottled material had lower fracture toughness than the nominal material and exhibited unstable crack growth.

“All of the cracks found during tanking as well as cracks fixed during manufacturing were located on stringers made with this mottled material.”

Furthermore, engineers were finally able to recreate the stringer crack failure seen on Discovery’s ET using the stringers from the partially-built ET-139 at the Michoud Assembly Facility (MAF).

By January 6, the all-powerful Program Requirements Control Board (PRCB) had directed teams to proceed forward with the radius block modification on well over 100 of Discovery’s tank stringers – a decision that further emphasized the drive for safety and understanding over launch date pressure.

With that, Discovery’s launch date was penciled in for February 24 or 25 as negotiations began with other ISS partners – specifically ESA (the European Space Agency) which was planning to dock their ATV-2 vehicle to the ISS at the same time that Discovery would now be ready for launch.

After negotiations concluded, it was decided that ATV-2′s docking on the morning of February 24 would permit the launch of Discovery later that day – something that had previously been ruled out due to communication and on-orbit requirements of the two vehicles and the ISS crew.

But as repairs to Discovery’s stringers kicked into high gear and things looked to be settling out for the veteran space vehicle, STS-133/Discovery crewmember Tim Kopra was injured and had to be removed from the mission as a result.

Within three days, Steve Bowen was assigned to the mission as Tim Kopra’s replacement, and NASA, in making the crewmember switch announcement, made it clear that Bowen’s experience on the previous Shuttle mission, STS-132/Atlantis, meant that he would need only moderate refresher training to perform the EVA activities originally assigned to Kopra.

As a result, Discovery would keep her February 24 NET launch date, and Nicole Stott and Al Drew would split the Flight Engineering responsibilities for launch and entry that Kopra was originally assigned.

By the end of January, Discovery’s stringers were modified and reviews had cleared the vehicle to return to the launch pad.

On the night of January 31/February 1 – the 8th anniversary of the loss of sister Columbia – Discovery was returned to the launch pad for what would be the 20th post-Columbia mission.

By all would not be as smooth sailing as hoped. The GUCP once again showed its temperamental side by failing an ambient leak check at the pad. (L2 Link).

The GUCP was disassembled, inspected, its two-part flight seals replaced, and reassembled. Subsequent ambient leak checks revealed a healthy GUCP, and all pad activities continued on schedule.

On February 15, the Ariane 5 launch vehicle successfully delivered the ATV-2 ESA resupply vehicle for the ISS into orbit – paving the way for a 24 February docking of ATV-2 to ISS and subsequent launch of Discovery later that same day.

With all approvals in place, the three-day countdown began on Monday, February 21.

The countdown proceeded flawlessly, and fueling of Discovery’s External Tank yielded absolutely no issues with the modified stringers or the GUCP.

Following the successful docking of ATV-2 to the ISS on the morning of 24 February, final preparations continued, the crew boarded Discovery, and the Countdown reached T-9mins and holding.

And then… it happened: the Eastern Range suffered a computer anomaly that prevented them from seeing the necessary safety information readouts from Discovery.

As the Range team worked the issue, the minutes continued to tick toward the end of the day’s short launch window.

At T-9mins and holding, Launch Director Mike Leinbach and his team decided to pick up the count and then hold at T-5mins if the Range issue had not yet been resolved.

With concurrence from all involved, Discovery’s Commander, Steve Lindsey, told the millions watching to “get ready to witness the majesty and the power of the Shuttle Discovery as she lifts off one more time.”

The launch countdown picked up and was indeed held at T-5mins for just over 3mins as the Range continued to work the issue.

In a heart-pounded final seconds, the launch team moved, with esteem calm and professionalism, to resume the countdown in time once the Range issue was cleared.

In the end, the team successfully resumed the countdown with only 1 second of LOX drain back hold time – the limiting launch window factor that day – remaining before a scrub would have had to have been called for the day.

But that one second was all that was needed.

To thunderous applause, numerous tears, an on-hand spectator number reaching close to a quarter of million people, and under crystal clear skies, the Space Shuttle Discovery began the display she and her sisters were best known for when she gracefully lifted off from LC-39A at the Kennedy Space Center at 1653.24 EST and made one final reach for the stars.

A true tribute to America’s space workforce, Discovery executed a flawless ascent and safely, successfully, and with pride delivered her six-member crew and mission payload to LEO.

Discovery docked to the ISS for the final time on 26 February 2011.

With her docking, a historic milestone was reached for the ISS – a complete family moment with the ISS supporting all of its support vehicles: Shuttle, Soyuz, Progress, HTV, and ATV.

During the mission, Discovery delivered thousands of pounds of external spares via the Express Logistics Carrier ELC-4 and thousands of pounds of internal supplies for the Space Station via the newly minted Permanent Multipurpose Module (PMM) Leonardo – a former Multi-Purpose Logistics Module (MPLM).

The addition of PMM Leonardo marked the final, permanent, pressurized module to be delivered to the ISS by the Space Shuttle fleet and NASA.

After nearly nine days of joint-docked operations, the ISS bid a final farewell to Orbiter Discovery after 13 missions to the orbital outpost.

On March 9, just before 12-noon, Discovery announced her triumphant return to the Kennedy Space Center before flying effortlessly over her Florida home and easing down onto Runway 15 at 11:58:14 EST.

By the time Discovery rolled to a stop on the Florida spaceport runway, she had achieved the distinction of having spent a cumulative total of 365 days (a full year) in space.

She was also the oldest-surviving Shuttle orbiter in the fleet upon completion of her final mission as well as the first Space Shuttle orbiter to successfully complete every single one of her missions – including all three Return to Flight missions following the losses of her big sisters Challenger and Columbia.

Discovery’s service to the human race began on 30 August 1984 with the launch of the STS-41D mission and ended on 9 March 2011 having lasted 26 years 6 months 6 days and 39 missions.

OV-105/Endeavour - An emotional high for the baby of the fleet:

For Endeavour, the 2011 calendar year began with direct knock-on effects from the on-going stringer crack issue of her sister Discovery’s ET.

The Space Shuttle Endeavour, the fifth and final space-worthy orbiter and sixth and final overall Space Shuttle orbiter constructed by NASA, began 2011 in her OPF-2 home as NASA hammered out a fix to the stringer issue on the External Tank.

Following the identification of root cause of the issue and implementation of the radius block modification, NASA made the decision to modify ET-122 – the External Tank Endeavour was to use on her final mission – despite the fact that ET-122 was an earlier-constructed tank than Discovery’s and was not constructed from the same material batch as Discovery’s mottled stringers were.

Nonetheless, the decision was made to ensure the highest safety factor for Endeavour and her returned-to-service ET.

In many ways, Endeavour’s final journey to space was a story of perseverance and rising above the odds.

Endeavour herself had always been a symbol of triumph from the throes of tragedy as her existence is owed entirely to the loss of Challenger, the sister she never knew.

Called upon for multiple important missions during her storied career, Endeavour was the Space Shuttle Orbiter that saved the Hubble Space Telescope in 1993 and the Orbiter that began construction of the International Space Station in December 1998 when she launched on the STS-88 mission to join the US’s “Unity” module with Russia’s Zarya module.

For Endeavour’s final mission, her Commander was none other than veteran Shuttle flier Mark E. Kelly – who, like his vehicle, was an amazing source of strength, hope, and inspiration throughout the early months of 2011 and throughout the STS-134 mission.

But the perseverance on STS-134 did not end with Endeavour or her crew.  Despite the fact that the STS-134 mission was the first of the final two missions to be added to the end of the Shuttle manifest (and the first of the final Shuttle missions whose flight was specifically mandated by Congress), her External Tank was a major source of pride for the NASA workforce.

Built in 2002, ET-122 was damaged during the landfall of Hurricane Katrina near the New Orleans MAF construction facility for the tanks. In fact, ET-122 was so damaged by the hurricane that it was completely removed from flight status.

Originally, Endeavour’s mission was supposed to use ET-138 – the final completed External Tank in the numerical sequence.

However, the addition of the STS-335 Launch On Need rescue mission for Endeavour mandated the need for another tank. Rather than complete fabrication and assembly of a new tank, ET-139, the MAF workforce was directed in November 2008 to restore ET-122 to flight status.

In addition to all the hurricane repair work that needed to be made, MAF workers also had to implement most of the RTF (Return To Flight) modifications mandated by NASA in the wake of the Columbia accident.

By early 2011, NASA decided to move ET-122 to STS-134/Endeavour’s mission so that Atlantis, if the STS-335 rescue mission was needed, could fly with a perfectly clean tank instead of the patched-up, but extremely safe, ET-122.

With Endeavour fitted with ET-122 and her SRB set, the entire stack arrived and LC-39A on March 10 with a target April 19 launch to the International Space Station.

With a rather traumatic opening week to her last visit to Pad-A, Endeavour’s flight managers were forced to review TPS damage zones on the baby of the Orbiter fleet after a tool was accidentally dropped from the RSS (Rotating Service Structure) and impacted Endeavour before landing on the zero-level deck of the MLP (Mobile Launch Platform).

The damage was very minor and no repairs were carried out on Endeavour.

At this time, as well, Endeavour was also cleared to proceed toward her April 19 launch date when Russian space officials confirmed that their Soyuz launch would only be slipping to April 4 and not deeper in April like originally thought.

But by the end of March, Russia and NASA were once again into negotiations on Endeavour’s launch date as a conflict between Russia’s Progress M-10M spacecraft and Endeavour’s missions arose.

Endeavour eventually lost the fight and was forced to move to an April 29 launch date – which she continued processing toward despite multiple rounds of adverse weather at the launch pad that triggered evaluations of the stack for storm damage.

Also at this time, NASA managers decided to cancel plans for a Soyuz fly-about of the docked Endeavour/ISS stack because of crew impact concerns should the Soyuz fail to re-dock to the ISS. (L2 Link).

By April 13, NASA formally extended Endeavour’s swan song mission by one day. With a newly extended mission, Endeavour entered what was thought to be her final launch countdown on April 26.

On launch day, as Endeavour’s crew prepared for their journey to the launch pad, an APU-1 heater issue presented itself. Initial attempts to troubleshoot the issue did not prove successful, and Launch Director Mike Leinbach scrubbed the April 29 launch attempt.

In the following week, the APU-1 heater issue was quickly traced to the Aft Load Control Assembly (ALCA-2) box. The ALCA-2 was Removed and Replaced, where a blown driver was subsequently focused on as the cause of the heater issue. (L2 Link).

STS-134 Specific Articles: http://www.nasaspaceflight.com/tag/sts-134/

With a new ALCA in place, Endeavour’s launch was retargeted for May 16.

For the final time, the countdown for the launch of Space Shuttle Endeavour began on Friday, May 13.

Thanks to the delay in the launch date, and agreements with Russia to undock the Soyuz TMA-20 for a nominal end of Soyuz mission landing during Endeavour’s docked mission, the formal plan to use the departing Soyuz to capture imagery of the docked Endeavour/ISS stack returned to mission planning.

On May 16, even though the weather looked borderline at best, all launch commit criteria aligned, leading to a final, unanimous “GO” for launch decision.

From the cockpit of Endeavour, Commander Mark Kelly said, “We endeavor to build a better life than the generation before and we endeavor to be a united nation. It is in our DNA to reach for the stars and explore. We must not stop.”

And mere minutes later, under overcast, grey, dreary skies, the Space Shuttle Endeavour roared to life for the 27th and final time as she thundered from the launch pad to begin her 25th and final voyage.

To many on the ground, including the launch team, Endeavour seemed to take just a little longer than normal to rise from the launch pad, turn, and begin her historic final mission to space – giving the 500,000 to 750,000 people in personal attendance the feeling of being able to see her for just a bit longer in all her glory.

Her launch was a moment of historical coincidence as well. Endeavour lifted off for the final time exactly 19 years to the day (May 16) after she landed to conclude her maiden voyage, the STS-49 mission in May 1992.

As she had 24 times before, Endeavour dutifully delivered her crew safely to orbit and performed a flawless docking to the ISS two days later.

Her mission marked the delivery of the premiere and exciting Alpha Magnetic Spectrometer to the ISS – an experiment designed to search for evidence of the existence of dark matter, anti-matter, and dark energy in our universe.

The mission also saw the delivery of ELC-3 – the final large delivery of external spares for the ISS – to the Station.

And, as we all remember and cherish, the mission also provided the stunning photography and video of Endeavour docked to the International Space Station from the vantage point of the departing Soyuz spacecraft. (L2 Link to 271 hi res flyaround photos)

But the greatest milestone of all came toward the end of Endeavour’s docked mission: US Assembly Complete of the International Space Station - achieved when Endeavour’s crew transferred and berthed Endeavour’s OBSS (Orbiter Boom Sensor System) to the orbiting outpost.

Thus, Endeavour was the orbiter that began and completed US assembly of the International Space Station.

(Animated image resized from hires/full screen version and sequence photo dumps on L2′s STS-134 Flight Day image section - several hundred megabytes strong – L2 Link.) 

After 11 days 17 hours 41 minutes of docked operations with the ISS, Endeavour bid a fond farewell to her orbital child.

Two days later, under the cover of darkness, Endeavour gallantly swooped down over her Florida home to end her career on 1 June 2011 at 0235 EDT.

To the very end, Endeavour was and always will be an iconic symbol of hope, a ship that inspires pride, awe, the quest for knowledge, and the determination to pick ourselves up and continue forward when adversity would rather us surrender.

After 19 years 24 days 6 hours and 55 minutes of service (May 7, 1992 at 1940 EDT to June 1, 2011 at 0235 EDT), Endeavour officially ended her tenure with the Space Shuttle Program. But she still remains our hope for a new tomorrow, an era when humans will regularly explore the space beyond the confines of our home world and push our boundaries of scientific knowledge and our quest of exploration.

OV-104/Atlantis - The Grand Finale of an American icon:

STS-135: The flight that wasn’t even manifested at the start of 2011.

Included in the NASA Authorization Act of 2011, which was signed into law on 11 October 2010, funding for the STS-135 mission remained in limbo while Congress remained incapable of reaching an agreement on the exact nature of the Fiscal Year 2011 calendar budget.

To this end, NASA continued procurement of mission hardware and software for the STS-335 contingency LON rescue mission which would have been used in the event that Endeavour became disabled during STS-134.

On 20 January 2011, NASA officially changed the mission designation number for STS-335 to STS-135 on internal documentation only (L2 Link), allowing teams to proceed with mission training and planning operations so that the continuing appropriations battle in Washington D.C. would not impact flight operations.

Finally, on 13 February 2011, NASA announced and confirmed that STS-135 would fly to the International Space Station regardless of whether or not appropriations from Congress materialized.

At this point, STS-135 became an officially manifested flight, making it one of the quickest missions to go from manifestation to liftoff in Shuttle Program history.

Undergoing a near one-year OPF-1 flow for STS-335/135, Space Shuttle orbiter Atlantis was mated to her ET/SRB stack.

Arriving at the launch pad at the same time as her sister Endeavour landed a few miles away to complete her last mission on June 1, Atlantis began a one month eight day pad flow.

On 15 June,  a tanking test was performed on the Atlantis/STS-135 stack to confirm a solid fix to Atlantis’s Tank’s stringers – which underwent the same modifications as Discovery’s and Endeavour’s tanks had.

The Tanking Test revealed a healthy tank and modified stringers while also revealing a hydrogen fuel valve issue in Main Engine #3 that, if it had occurred on launch day, would have resulted in a multi-day scrub.

Replacement of the valve was completed on 21 June, just one day after Atlantis’s payload was installed into her payload bay.

Despite a dismal weather forecast with only a 40 percent chance of acceptable weather, NASA launch managers decided to proceed with the launch attempt on 8 July.

Tanking operations began right on time at 0201 EDT and wrapped up three hours later with no issue.

In fact, Atlantis performed flawlessly during her countdown, with the only concern being the weather.

One hour before the scheduled liftoff, weather conditions improved and went GREEN, falling within Launch Commit Criteria rules. However, post-flight launch weather rules governing Return To Launch Site (RTLS) abort weather requirements could not be satisfied by the strict by-the-word standards.

However, the commitment clause for “Good Sense” allowed Launch Integration Manager Mike Moses to issue a formal waiver for the RTLS weather restrictions – giving all stations a GO status for launch – since the weather violation would have cleared by the time of an RTLS landing.

After Launch Director Mike Leinbach wished the crew “Good luck … on the final flight of this true American icon,” the countdown resumed and proceeded nominally from T-9mins to T-34seconds.

At T-34seconds, the Ground Launch Sequencer issued an automated hold at T-31seconds and inhibited Atlantis’s onboard computers from taking control of the countdown.

Prior to this, the final mission of the Space Shuttle to the ISS, the last time a Shuttle launch countdown was held at T-31secs was on the STS-88 mission – the very first Shuttle mission to ISS.

For Atlantis and STS-135, the hold was issued due to the failed indication of a complete retraction and latch of the Gaseous Oxygen vent arm.

The launch control team, one final time, demonstrated their extreme commitment to safety and professionalism as they calmly worked through the issue and used close circuit TV cameras at the launch pad to verify that the GOX vent arm was indeed fully retract and latched against the FSS (Fixed Service Structure) – thus confirming that the failed retraction and latching indication was a sensor error.

The glitch was ironic in many ways, as the GOX vent arm had never given the launch team an issue during the 150+ countdown retractions it was placed through during the life of the Program.

Furthermore, the GOX vent arm was a complete afterthought for the Shuttle Program and was only installed on the FSS after pad validation testing using test Shuttle Enterprise in 1979 revealed the need for the arm and vent system to prevent the build-up of dangerous ice at the top of the External Tank during the countdown.

STS-135 Specific Articles: http://www.nasaspaceflight.com/tag/sts-135/

With the issue resolved, the launch team released the hold, and Atlantis’s onboard computers took control of the vehicle and countdown. The time was 11:29:03.9 EDT on 8 July 2011.

In front of a world-wide audience and crowd of one million people at the Kennedy Space Center and surrounding cities and beaches, the Space Shuttle Atlantis came to life, majestically rose from her seaside launch pad, stretched her wings one final time, and went transonic as she punched through the cloud deck and disappeared from view – leaving only the sound of her engines as evidence of her flexing her muscles for the last time.

Atlantis, like her sisters, delivered her crew safely to orbit and docked to the ISS for the final time on 10 July 2011.

The mission saw the Atlantis crew deliver thousands of pounds of internal spares and supplies to the Station – stockpiling the outpost for several years to come.

The mission also delivered the Robotics Refueling Depot to the station, an external experiment deigned to help test robotic refueling technologies for future spacecraft and satellites.

On the final full day of docked operations, Atlantis Commander Chris Ferguson – at the farewell ceremony on the ISS – presented the ISS crew with a small American flag that was flown on the STS-1 mission by Shuttle Columbia on April 12-14, 1981.

The flag was fastened to the inner wall of the ISS and flanked by the STS-1 and STS-135 mission patches – a symbolic gesture signaling the end of the Shuttle program.

On July 19, Atlantis undocked from the ISS and performed a modified flyaround maneuver of the Space Station.

As she backed away from ISS for the last time, Atlantis silently slipped into the darkness of orbital night, the lights turning off on the historic program.

On July 21, Atlantis navigated her way through the fierce outer atmosphere of Earth, taking aim on the Kennedy Space Center for a pre-dawn landing on runway 15.

(Animation created from some of the 114 hi res photos (all available in L2) taken by Mike Fossum on the ISS)

Less than 10 minutes before landing, the ISS made a breath-taking visual pass directly over the Kennedy Space Center in a final salute to the Shuttle Program, heralding Atlantis’s arrival to her permanent home city.

At 05:57:54, Atlantis descended from the darkness and touched her wheels to the pavement at the Shuttle Landing Facility for an emotional finale to her legacy and the legacy of the Space Shuttle Program.

Upon “wheels stop,” the final Shuttle Commander thanked all the men and women who worked on the program and the vehicles over the preceding 30+ years. And in a touching moment, Commander Ferguson also thanked the five flight vehicles themselves for protecting their crews and enabling the expansion of our knowledge and quest for science.

Less than 30 minutes after landing, Atlantis fell silent for the final time.

It was over.
 
Final Reflections on a legend:

With that final Shuttle landing came a moment of joy, sadness, grief, prolonged contemplation, but above all PRIDE in an amazingly complex set of vehicles that inspired countless numbers around the world, flew more people to space than any other spacecraft thus far (and for many, many decades to come), and helped bridge the gap between nations and forge unprecedented alliances in space.

For 30 years, 3 months, 8 days, 22 hours and 57 minutes (April 12, 1981 at 0700EDT to July 21, 2011 at 0557 EDT), the five space-worthy Shuttle orbiters spent a combined total of 1,332 days 1 hour and 36 minutes in space, completing 21,152 orbits of Earth over 548.2 million miles.

All five Shuttle orbiters deployed a combined total of 66 satellites, completed 46 rendezvous with an orbital space station (9 to MIR and 37 to ISS), and carried a combined total of 827 crewmembers (some more than once) into space.

For the final breakdown:

Discovery (OV-103): 39 missions; 365days 12hrs 53mins in space; 5,830 orbits of Earth; 148.2 million miles travelled; 31 satellites deployed (including the Hubble Space Telescope); 14 space station dockings; 252 crewmembers.

Atlantis (OV-104): 33 missions; 305days 7hrs 47mins in space; 4,848 orbits of Earth; 125.9 million miles travelled; 14 satellites deployed; 19 space station dockings (a world-wide record she will keep for decades to come); 207 crewmembers.

Columbia (OV-102): 28 missions; 300days 17hours 41mins in space; 4,808 orbits of Earth; 125.5 million miles travelled; 8 satellites deployed; 160 crewmembers.

Endeavour (OV-105): 25 missions; 299days 3hrs 19mins in space; 4,671 orbits of Earth; 122.8 million miles travelled; 3 satellites deployed; 12 space station dockings and one space station rendezvous and grapple; 148 crewmembers.

Challenger (OV-099): 10 missions; 62days 7hrs 56mins in space; 995 orbits of Earth; 25.8 million miles travelled; 10 satellites deployed; 60 crewmembers.

And while the Shuttles’ missions are behind them, and their engines and APUs forever silent, we wish them and all who have flown aboard them, and all who have worked on them, and all who dedicated theirs lives to making them fly Godspeed in whatever the future may hold.

The Space Shuttle Program, the five orbiters, and their dedicated workforce leave behind an unprecedented legacy of achievement – and a legacy that must never be forgotten, a legacy where all were taught by example “To strive, to seek, to find, and not to yield.”

But moreover, the five Shuttle orbiters made a thousands-strong workforce incredibly proud.

To all of the NASA engineers, all of the astronauts, the entire NASA workforce (including those contractually employed by Pratt & Whitney, Boeing, ATK, Lockheed, USA), and all those whose names we never heard but nonetheless worked silently and many times without recognition in support of a program that you whole-heartedly believed in, we give you our resounding thanks and gratitude.

Without you, this program would not have been what it was.

The Shuttle program has come to an end, but the legacy of the program and those who worked and flew aboard the Shuttle, as well as those who will continue the dream of human space exploration, will forever carry on.

And so, for the final time, to Enterprise (1977-1985), Columbia (1981-2003), Challenger (1983-1986), Discovery (1984-2011), Atlantis (1985-2011), and Endeavour (1992-2011), you will always have our eternal thanks and gratitude for all that you have enabled the human race to learn and discover about not only the universe and our home planet, but also about ourselves and our ability to work together to achieve common and mutually-supportive objectives.

It was an incredible journey. And those of us who were a part of this great program, no matter how small a part, will never forget a single part of it or the Orbiters and people who made it all possible.

Thank you.

Please note: Clickable links with (L2) references point directly to cited L2 content. Such content is only available to L2 members (please ensure you are logged in). All other clickable links point to NSF articles and open content.

To read about Atlantis and her sisters – from birth, processing, every single mission, through to retirement, click here for the links:
http://forum.nasaspaceflight.com/index.php?topic=25837.0

Click here for the amazing MaxQ Entertainment STS-135 Mission Review Music Video:
http://forum.nasaspaceflight.com/index.php?topic=26178.0

(Images: Via Larry Sullivan and Brian Papke, MaxQ Entertainment/NASASpaceflight.com, L2 and L2 presentations and NASA. To join L2, click here: http://www.nasaspaceflight.com/l2/)

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 Solid Rocket Boosters:

As expected based on an excellent flight history, the Solid Rocket Booster (SRB) systems on STS-134/Endeavour performed extremely well during the May 16, 2011 launch. Only five items of interest of were noted on the booster systems during the standard In-Flight Anomaly (IFA) baseline report to the Space Shuttle Program.

In fact, only two of the five reportable squawks on the SRBs were worthy of IFA status: a Right Hand (RH) SRB main parachute failure and a separation debris event recorded by one of the RH engineering cameras on the SRB itself.

For the parachute failure, the SRB IFA presentation notes that a “Parachute tear was observed during diving operations. DAS video verified failure.”

The parachute failure, identified as a tear in the main chute, did not affect ascent performance of the SRB systems and has been classed in the Criticality 3 category.

Moreover, the loss of only one chute still ensured the safe splashdown and recovery of the SRB. Nonetheless, an SRB IFA was declared and an Anomaly Resolution Team (ART) formed to investigate the failure.

To date, the ART has reviewed DAS accelerometer data, which indicates that the “second disreef occurred earlier than experience although within requirements.”

Further post-flight inspections revealed damage at “gore #26″ on the parachute, damage that extended through the length of the chute.

An initial fault tree has been developed and a detailed inspection and photographic work-up of the damage hardware and pre-flight processing images is underway.

While investigators will make every effort to find root cause for this problem and ensure that it does not exist on STS-135′s SRBs, it is highly unlikely that this issue would cause any kind of delay to the STS-135 mission given that flight’s status as the final Program Flight.

However, the second IFA declared for STS-134′s SRBs is of a more serious nature, though significant progress is being made and is not expected to be an issue for STS-135′s launch on July 8.

This IFA was declared to document the liberation of a single piece of debris at MET (Mission Elapsed Time) 125.242 seconds near the RH SRB forward attach point to the External Tank (ET) during SRB separation.

“Debris appeared metallic and cylindrical. SRB Anomaly Resolution Team formed,” notes the SRB IFA review presentation – available for download on L2.

The ART quickly identified all potential sources for the debris from the forward assembly and compiled supporting and refuting data for each item to expedite the review and identification process.

This refuting and supporting data was compiled in part based on post-flight inspections of the SRB structure and systems.

From this compiled list of candidates, two gained mention in the SRB IFA review, with the first being a Ground Strap Coupler which was found to be missing during post-flight inspections.

The Ground Strap Coupler is used as a connection between the returned and non-returned ground straps between the SRBs and the ET.

The second though less-likely source for the debris is the Separation Bolt Lock Pin which is used to stake an insert on the ET-side of the hardware.

Since the ET-side of the hardware burns up in Earth’s atmosphere follow Orbiter/ET separation, it cannot be confirmed whether or not this component was still attached to the ET hardware following SRB separation.

Reusable Solid Rocket Motors:

As with the SRBs, Endeavour’s RSRM components performed splendidly during both of Endeavour’s 43-hour launch countdowns, with the IFA report from ATK – the parent company of the RSRMs – indicating that “All RSRM countdown parameters were within LCC/OMRS limits and within family.”

Likewise, ATK’s IFA presentation to the Space Shuttle Program (SSP) revealed that the performance of both STS-134 motors and their associated Booster Separation Motors (BSMs) was excellent and “well within CEI requirements.”

At the time of the IFA review on June 17, RSRM post-flight hardware evaluations were ongoing at the Kennedy Space Center, as were BSM inspections.

In Utah, at the production facility of the RSRMs, nozzle disassembly began June 16.

To date, no (ZERO) IFAs on the RSRMs have been declared and only eight squawks have been identified for further evaluation. Of the eight squawks, only six gained specific notes from ATK as part of their thorough IFA presentation to the SSP.

The first such squawk related to “sooted foam loss” from the Right Hand (RH) motor’s center stiffener ring. 

As noted in ATK’s IFA presentation, “An area of foam loss was noted at approx 300-degrees on the RH center stiffener ring. Exposed surface was heavily sooted.”

The resulting exposed area was elliptical in shape and carried dimensions of ~6inches x 3inches.  An engineering estimate on the mass of the missing stiffener foam registered at 0.2  lbs – with a conservative risk assessment prediction of 0.218 lbs.

Analysis of the area indicates that the foam loss occurred AFTER the rocket motors had separated from the STS-134 stack. This was confirmed via RH RSRM photos showing “a porta-pull location (on-motor pull test for foam process verification) on the RH motor. Sooted area in the photo is exposed during the foam pull testing and sees full ascent, plume impingement and reentry heating.

“Right hand photo shows Foam missing surrounding the sooted area was due to splashdown as shown by the lack of any stain or darkening.”

These photos were then compared to photos of the LH RSRM which displayed pieces of thermal curtain embedded in the stiffener foam. “Foam loss to bare case is lightly sooted showing this to be a reentry event with exposure to less than the full reentry heating,” notes the IFA presentation.

Click here for specific SRM/RSRM Articles: http://www.nasaspaceflight.com/tag/srb/

Here, the LH impact confirmed previous held beliefs that thermal curtain impacts on the RSRM stiffener foam can cause “bare case” exposure to the RSRM during the reentry environment.

“Comparison of the lab analysis of the residues in the three sooted areas and earlier test results showed that the RH foam loss occurred early in reentry heating.”

Therefore, there are no concerns with materials or foam processing and this squawk is not a risk to STS-135/Atlantis’s ascent next month as the foam loss does not violate previous flight rationale.

The second squawk mentioned in the IFA report was due to an unknown material on the RH Nozzle-to-Case Barrier O-ring.

The presentation notes that an “Unknown material (white/clear) was found on the surface of the barrier O-ring.”

Initial lab results indicate that the material is an adhesive from Teflon tape that is used in the area during nozzle installation.

“Material is suspected to have been moved over O-ring footprint during disassembly as no indent was noted on O-ring,” added the presentation.

This is not a constraint to STS-135 since the material is “gel-like and compliant and would not indict nozzle-to-case joint leak check even if was on footprint.”

The third squawk was a grease blockage of a leak check groove in the LH Igniter Outer Gasket. “Excessive grease was observed in the STS-134 (RSRM-113) leak check transmission groove at approximately 135 degrees,” notes the STS-134 RSRM review presentation.

The grease is usually located in the void region of the gasket sealing element and can be removed from the groove region by Mylar film.

The problem here is that excessive grease could “extrude from the void area during final bolt torque and although undesirable, excessive grease migration into the groove after leak check does not affect sealing or leak check validity.”

Since the igniter outer joint leak test is performed at a low bolt torque of 20 – 25 ft-lb, excess grease will not extrude from the void region until torque values are higher than 150 ft-lb. Therefore, there is no way for the grease to block the leak check groove at the leak test torque level, and there is no concern for STS-135.

The fourth squawk pertained to missing material on the LH and RH outer gasket primary seal cushion.  As noted by the IFA presentation, “Damage was observed on the forward face seal cushion of the STS-134 (RSRM-113) outer gasket primary seal in-line with the leak check thru-hole.

“The gasket crown (not the cushion) is the sealing element for the gaskets and is deformed during installation to provide the seal.”

A similar issue was noted on a 5-segment Demonstration Motor (DM-1) in 2009.

Here, the flight concern revolves around whether or not rubber damage could compromise the gasket seal (crown) and potentially “challenge” other hardware functions.

Moreover, “Recent install tool change, in combination with inherent hardware tolerances, show increased propensity to result in leak check thru-hole partially over rubber in assembled condition.”

Therefore, rubber can extrude into the thru-hole at assembly and at motor pressurization, a dome movement could result in a shear-off of extruded rubber cushion.

However, there are “No credible scenarios for potential overlap to result in inadequate leak check, damage to crown, or misplaced rubber material to affect seal integrity.”

STS-134 Specific Articles: http://www.nasaspaceflight.com/tag/sts-134/

A review of all data on the RSRM-114 set on STS-135 revealed no potential overlaps with the crown.

The penultimate squawk listed on the STS-134 RSRM IFA review was taken to document a foreign hair-like material on threads of the LH aft vent port top plug and LH aft vent port closure plug.

The IFA noted that an impression on the O-ring surface was noted after the hair-like materials’ removal. The hair-like materials are currently being analyzed to determine precisely what they are.

“First squawk was written to document and  sample for lab analysis a foreign (hair like) material on threads of the LH aft vent port top plug. Second squawk was written to document and sample for lab analysis a foreign (hair like) material on LH aft vent port closure plug,” noted the IFA presentation. 

“An impression was also observed remaining in O-ring surface. At this point, the two fiber appear similar and are being analyzed to determine type and size.”

Finally, the last squawk on the STS-134 RSRMs was a retainer surface indication on the LH igniter outer gasket.

“Discontinuity noted on metal (retainer) surface of outer gasket on LH igniter.”

The gasket has been shipped to Utah for lab analysis.

(All images via L2 acquired presentations – STS-134 IFA Review for SRB and RSRM. Post STS-134 coverage of Endeavour is continuing in L2, which will follow Endeavour all the way to her retirement home in California).

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STS-134 Post Mission Deservicing Latest:

A large amount of work is being carried out on Endeavour inside her Orbiter Processing Facility (OPF-1), as post mission safing and initial deservicing work is carried out on the now-retired orbiter.

Engineers have already removed the “44 door” for midbody access, removed the Waste Containment System (WCS) and are continuing with the removal of the numerous cameras on the Remote Manipulator System (Shuttle Robotic Arm).

The main focus of work over the next few days revolves around the preparations to remove Endeavour’s Forward Reaction Control System (FRCS) – which will eventually be shipped to White Sands – and the dome heat shields around Endeavour’s three Space Shuttle Main Engines (SSMEs).

“The PLBDs (Payload Bay Doors) were opened earlier in the week. In work with removing the payload at this time,” noted KSC Ground Operations via the latest Shuttle Standup/Integration report (L2). “Working preps for engines. Engines will start coming out late next week.”

First on the list of SSME related tasks was the requirement to position the SSMEs engine bells (nozzles) – and other hydraulic powered systems – to their correct positions for the upcoming work.

“Hydraulic operation to position the SSME’s to null, RSB (Rudder Speed Brake) to closed, elevons to null, body flap down have been completed,” noted the NASA Test Director (NTD) report (L2), adding that technicians took the opportunity to check the SSME controller which suffered from a minor – and short-lived – issue during ascent.

“The SSME controller was powered up to troubleshoot a Low Pressure Fuel Turbo Pump (LPFTP) discharge pressure transducer that failed low during ascent. Troubleshooting was unable to recreate the anomaly. The sensor will be removed and taken to the design center for further analysis.”

Pratt & Whitney Rocketdyne/KSC – who care for the engines that may find thsemselves with a role on the Space Launch System (SLS) – also noted that an X-Ray took place on the sensor, which also found nothing amiss.

“No anomalies have been found so far during testing,” confirmed their notes on the Standup report. “The sensor was removed and sent for x-rays. A micro-focus X-ray was performed, and no anomalies were found.”

SSME dome heatshield and body flap carrier panel removal began on Friday, while the heatshield removal will continue through the weekend.

Engineers have also removed the three Flow Control Valves (FCVs) from Endeavour’s Main Propulsion System (MPS), ahead of being shipped to California for inspection.

Although these valves will never be involved in another shuttle launch, the intense inspections – implemented since part of a poppet on a valve liberated during STS-126 – are still being carried out as part of the routine due diligence approach that is commonplace for the Space Shuttle Program (SSP).

“USA Logistics (USA/KSC) In preps to ship the FCV off OV-105 (Endeavour once they are removed. Vacco is ready to receive them and start the inspection, and have data for the Engineering team,” added noted on the Standup report.

STS-134 Specific Articles: http://www.nasaspaceflight.com/tag/sts-134/

“(Managers) added that some might wonder why the FCVs are being looked at since we have the ship set and the spare for OV-104 (Atlantis). Orbiter just wants to follow through and ensure that nothing is discovered from these FCVs that might call into question the flight rationale being used.”

Brake Fire Latest:

Engineers are continuing to evaluate the observations of a small fire – lasting around 40 seconds on one of Endeavour’s Left Main Landing Gear brakes – at the end of the braking period as the orbiter came to a stop on the SLF after landing.

“In response to the very shortlived brake fire observed during landing of STS-134, a Problem Report (PR) was (created). Per the PR, brake samples were taken, the rolling resistance of the left inboard wheel was measured, and the wheel and tire assembly was removed,” noted investigation notes (L2).

With engineers removing the tire/wheel from the left hand inboard landing gear, before performing a thorough inspection, no real indications of a fire have been observed. Even a couple of strips of plastic tape in the location showed no indications of being over heated, which is highly unusual for an incident of this nature.

The next step was to apply hydraulic pressure to the brakes to see if there are any signs of an hydraulic leak. It was expected that a very small hydraulic leak would be observed, leading to a potential root cause. However, the checks came back nominal.

One of the investigation photos of the disassembled wheel show the what the brake assembly looks like after Endeavour returned to her OPF, with an engineering explanation noting the hardware in view consists of rotors and stators, which are discs of the carbon/carbon material.

The stators fix to the axle and the rotors spin on the axle, with the two parts forming a sandwich configuration.

Another photo shows the interior of the wheel, with the torque bars bolted to the wheel. When the wheel is put in place on the axle, these bars engage the slots on the brake rotors, which basically locks the rotor to the wheel.

On the inside end of the axle assembly there is a ring of hydraulic pistons around the entire circumference of the axle, which push against the entire brake assembly forcing the rotors and stators together to result in the braking action.

It was also noted that the amount of dust seen on this wheel was not out of the ordinary, but on the high end of what the engineers normally see.

So far engineers have found no obvious evidence of the fire, and the hydraulic pressurization test of the brake pucks did not show any leakage, meaning the event may be classed as an Unexplained Anomaly (UA).

“On the STS-134 brake fire, the team has been looking at the brake area extensively but has not really found anything yet,” noted the Orbiter Project Office (OPO) on the Standup report.

“They know there are no hydraulic leaks, did not find excessive amounts of brake dust or extra grease. There no evidence of the fire except that one of the heat shields appears to be a little darker than the others. They will continue to examine the area and take samples.”

Classing the incident as an UA is allowed, providing the problem is orbiter specific and unlikely to occur again – as in the case with Endeavour’s incident.

However, it will be reviewed ahead of Atlantis’ mission, per the STS-135 Flight Readiness Reviews (FRRs) – which are starting to ramp up ahead of the SSP FRR on June 21, which is the main review ahead of the launch date-setting Agency FRR one week later.

“They (engineering) are nearing the point that they may not know what caused it, but it is a situation that would not be catastrophic and should not happen again,” added the OPO. “This will be discussed at the FRR.”

(Images L2 Content. Post STS-134 coverage of Endeavour is continuing in L2′s specific section, which will follow Endeavour through post flight all the way to her retirement home in California).

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Post STS-134 Early Reviews:

Endeavour put the finishing touches to her honorable legacy, by leaving the International Space Station (ISS) – she helped build – in a good configuration for its long term future, along with installing the flagship AMS-2 particle physics payload to the outside of the orbital outpost.

In total, her mission was the 134th mission supporting the Space Shuttle Program (SSP), completing 4,677 orbits of Earth for a total of 122,833,151 miles and 299 days in space – as noted in a loving tribute via the normally technical NASA Test Director (NTD) report. 

(Animated image resized from hires/full screen version and sequence photo dumps on L2′s STS-134 Flight Day image section - several hundred megabytes strong.) 

“First launched in May 1992 on STS-49, career highlights include: the first 3-person EVA and longest since Apollo 17 (STS-49), the first Hubble servicing mission (STS-61), delivery of the Unity module to the Zarya module of the ISS (STS-88), 11 missions supporting ISS assembly and crew rotation; including delivery of the Kibo module (STS-123), Node 3/Cupola (STS-130) and, most recently, the Alpha Magnetic Spectrometer (STS-134) among many other significant contributions to our nation.

“Welcome home Endeavour! Thank you for your service to our country’s Human Spaceflight Program.”

Click here for Endeavour’s full history:
Part 1: http://www.nasaspaceflight.com/2011/04/space-shuttle-endeavour-a-new-beginning-part-i/
Part 2: http://www.nasaspaceflight.com/2011/04/ov-105-endeavour-a-long-standing-dream-realized/

Apart from the cosmetic damage to her Thermal Protection System (TPS) – which was ably cleared by the Damage Assessment Team (DAT) and the Mission Management Team (MMT) via a Focused Inspection (FI) – Endeavour’s performance on orbit was once again impressive.

Her final mission milestones, prior to coming to one final wheels stop under her own power, all went to plan, according to the Mission Evaluation Room (MER) post landing evaluation report (L2).

“The STS-134 mission was successfully completed with a landing at Kennedy Space Center (KSC), Florida. Both Payload Bay Doors (PLBDs) were closed nominally by 153/02:48:23 GMT [15/13:54:16 Mission Elapsed Time (MET)] in preparation for landing,” noted the documentation.

“The deorbit maneuver for the first landing opportunity at KSC, a dual-engine firing, was performed on orbit 248 at 152/05:29:03 GMT (15/16:32:35 MET). The burn was 158.3 sec in duration with a Differential Velocity of 298.4 ft/sec. The resulting orbit was 23.2 by 188.5 nmi. Entry interface occurred at 152/06:03:06 GMT (15/17:06:38 MET).

“The main landing gear touchdown occurred KSC runway 15 at 152/06:34:50 GMT (15/17:38:12 MET). The drag chute was deployed at 152/06:34:53 GMT. The nose gear touchdown occurred at 152/06:35:00 GMT. Drag chute jettison occurred at 153/06:35:19 GMT. Wheels stop occurred at 152/06:35:33 GMT. The rollout was normal in all respects.”

While the return was – as noted – normal, a later report noted Endeavour’s rollout down the SLF was the second shortest in the history of the Space Shuttle Program (SSP), notable not least because no Detailed Test Objective (DTO) into a “hard braking” test was requested for this landing.

A related investigation is also being carried out on observations of a small fire – lasting around 40 seconds on one of Endeavour’s Left Main Landing Gear – was observed at the end of the braking period as the orbiter came to a stop.

According to Kennedy Space Center (KSC) sources, the teams which greeted the orbiter noticed no indications of the brief fire during the runway inspections, nor did they find any truly discernible indications of a fire after they gave Endeavour a thorough inspection on Wednesday. 

It was only during reviews of the landing videos when it was raised to managers, leading to the investigation. Part of the review will be into the braking force applied during rollout, which is believed to have been somewhat “above normal”, given the second shortest roll out in the program.

The incident also impacts on Endeavour’s Transition and Retirement (T&R) processing, given the brakes on the orbiter were set to remain on the vehicle. It is now likely they will be removed to allow for a thorough investigation.

Currently, the two most likely causes are suspected to be excess grease on the wheel/axle or a leaking hydraulic puck, in tandem with the heavier than normal braking. Engineers are expected to recharge the hydraulic pressure and inspect for a puck leakage or any other hydraulic system leakage.

STS-134 Specific Articles: http://www.nasaspaceflight.com/tag/sts-134/

Such small fires have been seen on commercial airlines before, and it is understood the fire held no threat to the orbiter or her crew’s safety. Any increased temperatures from the fire would have felt like a tickle to Endeavour, given she had just raced through the thousands of degrees of heat during re-entry.

Had the fire of been larger, fire trucks would have left their staging point and been on site within seconds.

A full overview is expected at the Program Requirements Control Board (PRCB) level In Flight Anomaly (IFA) Review, scheduled for June 16 at the Johnson Space Center (JSC).

After coming to a stop, Endeavour – panting like a racehorse and breathing fire through her Auxiliary Power Unit (APU) vents near her Rudder Speed Brake (RSB) – was run through the post landing check-list by her crew.

This resulted in the sober sound of her three APUs being shutdown one by one, as the vehicle fell silent one final time.

The last APU was shutdown 20 minutes and 24 second after landing, which also concluded their successful use by Endeavour after the trouble caused by a heater system string pre-launch - while her total STS-134 flight duration was marked at 15 days, 17 hours, six minutes and 37 seconds.

After initial safing and integration with her oddball collection of convoy trucks, tow back to her Orbiter Processing Facility (OPF) began at 06:15 EDT on the morning of landing, arriving back into the arms of her engineering teams 75 minutes later.

Endeavour was then placed into S0069 Post Mission Integrated Roll-In Operations, which is an initial staging point ahead of the down-mission processing flow.

“S0069 Integrated roll-in operations are essentially complete. The left and right umbilical mates were completed along with GSE (Ground Support Equipment) connection to the Freon and Purge systems,” added the NTD reports for Endeavour’s post STS-134 flow.

“Fuel Cells were secured Wednesday at 14:32 EDT. Vehicle was Jack/Leveled with access platforms configured around the vehicle. PRSD (Power Reactant Storage and Distributation) residual cryo drain at 10:00 EDT (and now complete). Fuel Cell inerting complete.

“OMS (Orbital Manuvering System) QD (Quick Disconnect) access and scupper installation taking place Friday with trickle purge activation on Saturday. Payload Bay strongbacks installed Friday for opening on Monday afternoon. Weekend work: Aft access installation, trickle purge initiation.”

Endeavour will soon head into a schedule of T&R operations which will closely match her older sister Discovery, with the removal of her three Space Shuttle Main Engines (SSMEs) to be placed into storage for “potential” use on the Space Launch System (SLS) – pending a final configuration decision by NASA HQ (major article next week).

A total of 12 SSMEs – three flight sets and one spare set – are being saved for the SLS, a vehicle which is now heavily expected to be a form of Shuttle Derived (SD) Heavy Lift Launch Vehicle (HLV), allowing for a role in powering the new vehicle’s first stage during the opening flights, expected to begin in 2016.

The three orbiters are currently baselined to each receive three Replica Shuttle Main Engines (RSMEs) – made from previously scrapped nozzles and installed via an adaptor – for when the vehicles retire to their exhibitions.

Like Discovery, Endeavour will have both of her OMS Pods removed, along with her Forward Reaction Control System (FRCS), leaving a bare looking orbiter, prior to further replica replacements being installed.

The aforementioned propulsion systems will be shipped to the White Sands facility for deservicing and safing, with Discovery’s FRCS current in the Hypergolics Maintenance Facility (HMF) in preparation for its trip to New Mexico.

(Images via Larry Sullivan – MaxQ Entertainment/NASASpaceflight.com, L2 Content and NASA.gov. Post STS-134 coverage of Endeavour is continuing in L2, which will follow Endeavour all the way to her retirement home in California).

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STS-134 Latest:

Following undocking and preparations for Entry – which included the Flight Day 15 Flight Control Surfaces (FCS) checkouts, Reaction Control System (RCS) hotfire and communication checks with ground stations, Endeavour’s crew worked towards the first landing opportunity with a high degree of confidence due to favorable weather forecasts.

As expected, the Go was given to conduct the deorbit burn – which took place at 01:32 Eastern.

Only two issues of late have been evaluated by engineers at the Mission Evaluation Room (MER), both of which related to the checkout operations.

One “funny” – MER terminology for a minor issue – was noted on the HUD (Heads Up Display) Checkout, relating to a configuration issue, which was soon resolved. The second related to Fuel Cell 2′s self test health and status sensor, which is used to test the status of the three Fuel Cells every seven minutes.

“Fuel Cell 2 Substack 1 CPM Intermittent Self Test Fail has occurred several times in the last 24 hours. The Fuel Cell is performing nominally but is being analyzed at each days Fuel Cell Monitoring System downlink,” noted MER information (L2). “Per flight rule a Bus Tie was performed and no other immediate actions are needed.”

In taking the first opportunity, Endeavour  had her wheels on the ground at the SLF at 02:35 EDT. Had controllers at the Mission Control Center (MCC) in Houston decided to wave off the first attempt, a second opportunity existed, which would have resulted in a landing at 04:11 EDT.

(Animated image resized from hires/full screen version and sequence photo dumps on L2′s STS-134 Flight Day image section - several hundred megabytes strong.) 

Given the timing of the return to Florida, Endeavour passed over her older sister Atlantis, as she heads into the final feet of her rollout to Pad 39A for her STS-135 launch on July 8.

The first major milestone of the de-orbit preps revolved around tasks associated with the closing of the Payload Bay Doors. Cameras in the Payload Bay were used to monitor the four radiator retract hoses as the doors closed, while the crew watched for a set of good latch indications via their own instrumentation.

Another key element of returning home was the start of her three Auxiliary Power Units (APUs), one of which was the cause of STS-134′s launch delay, following APU-1′s Fuel Test Line and Fuel Service Line ‘B’ heaters failing to activate during pre-launch operations.

STS-134 Specific Articles: http://www.nasaspaceflight.com/tag/sts-134/

The failure was deemed to be persistent with both ground command and panel switch activation, which is an off-nominal condition for an orbiter, as much as the redundant ‘A’ heaters performed nominally. An exposed conductor was deemed to be the root cause, with no heater system issues reported during Endeavour’s mission.

However, another APU issue was overviewed by the Mission Management Team (MMT) during the flight, relating to failed Gas Generator (GG) bed heater on APU-2. No impact to Endeavour’s mission was listed, and the fault has no relation to the APU-1 heater issue.

Several actions were presented to the MMT in the event of further failures, mainly involving temperature control on the system. Most of these actions were designed in the event of additional issues during the remainder of Endeavour’s docked mission, which did not occur, along with some get-wells ahead of entry.

“(In the event of) Dual Heater Failures occur after undock: Ambient temps are predicted to be above freezing in the undock timeframe. No action to prevent freezing required,” noted one of several expansive MMT presentations (L2).

“Prior to entry, attitude will be taken to warm the GG bed to around 84 degrees F so that the APU can be used for entry.”

However, the system has not suffered any additional problems, allowing for no changes to Endeavour’s return stance, and the expected nominal performance of the entire APU-2 system during Entry. All three APUs performed as advertised, as she arrived back on the runway in Florida, breathing fire from her vents and panting away like a racehorse.

The Final Landing of Endeavour:

For 19 years, the Space Shuttle orbiter Endeavour (OV-105) has braved the harsh serenity of space, taking with her time and time again the hopes, dreams, aspirations, and thanks for a dedicated workforce and public. 

Click here for Endeavour’s full history:
Part 1: http://www.nasaspaceflight.com/2011/04/space-shuttle-endeavour-a-new-beginning-part-i/
Part 2: http://www.nasaspaceflight.com/2011/04/ov-105-endeavour-a-long-standing-dream-realized/

She has been, and always will be, an iconic symbol of hope and perseverance, a vehicle rising from the ashes of tragedy to take the human race to new heights in the pursuit of scientific knowledge and understanding.

Heading into landing, Endeavour will complete her 4,671st and final orbit of Earth, returning to her home after a cumulative sojourn of 299 days in orbit of planet Earth.

After 122.8 million miles and 19 years 24 days 6 hours and 55 minutes of service (May 7, 1992 at 1940 EDT through June 1, 2011 at 0235 EDT), the British-named Endeavour will gently ease to a stop on the Shuttle Landing Facility at the Kennedy Space Center.

Approximately half an hour later, she will fall silent for the final time – leaving only one Space Shuttle orbiter (middle-child Atlantis/OV-104) in service to NASA for the first time since the end of 1982 – when Challenger joined pioneer Columbia to increase the Shuttle fleet to two.

Upon her return from STS-134, what will be Endeavour’s 18th landing at the Kennedy Space Center, the good ship will be towed to OPF-1 (Orbiter Processing Facility 1) near the VAB to undergo post-career deservicing and Transition and Retirement processing.

Like her British sailing ship namesake from the 18th century, the Space Shuttle Endeavour has never faltered in her mission to expanding our understanding of the scientific frontier.

From saving the Hubble Space Telescope, to broadening our knowledge of maneuverability in space, to her innumerable scientific studies and experiments, to the knowledge she gave us about the contours of our home planet, and to the International Space Station (which will be one of her longest-lasting legacies), Endeavour has constantly taken us to new and unprecedented territories.

She has been, and will be for countless generations to come, a ship that inspires pride, awe, the quest for knowledge, and the determination to pick ourselves up and continue forward when adversity would rather us surrender.

Endeavour, in simplest terms, is our hope for a new tomorrow. An era when humans regularly explore the space beyond the confines of our home world and push our boundaries of scientific knowledge and our quest of exploration.

To paraphrase the words of Endeavour’s final Commander, spoken in the minutes before she took to the skies one last time, “We endeavor to build a better life than the generation before and we endeavor to be” united nations. “It is in our DNA to reach for the stars and explore. We must not stop.”

And as Barbara Morgan (Mission Specialist on STS-118/Endeavour) remarked upon Endeavour’s return to service from the Columbia accident, “there’s a great sense of pride to be able to be involved in a human endeavor that takes us all a little bit farther. When you look down and see our Earth, and you realize what we are trying to do as a human race, it’s pretty profound.”

To the good ship Endeavour, we give you our heartfelt thanks and gratitude. As your sister Discovery before you, you have not failed us, because we have never failed you. To you and your history will we commit our future – driving us forever outward into space.

THANK YOU, Endeavour, for an incredible and deserved job well done.

(Images via L2 presentations, images and content). Extensive coverage is being provided on the news site, forum and L2 special sections – the latter of which is the world’s best front row seat to Shuttle missions. With specific and extensive flight day coverage, from interactive “one stop” FD live coverage in the open forum, to internal documentation, photos, videos and content in the specific L2 FD areas. Coverage will continue post-mission).

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Click here for ENDEAVOUR UNDOCKING AND STORRM OVERVIEW ARTICLE:
http://www.nasaspaceflight.com/2011/05/sts-134-endeavour-storrm-final-farewell-to-iss/

Following the preliminary clearance of all areas of Endeavour’s TPS on FD-5, less the multi-tile gouge area between Endeavour’s Right Hand MLGD (Main Landing Gear Door) and Right Hand ET Umbilical door, Endeavour’s flight crew was instructed to proceed with a focused inspection of the damage location.

Post Undocking TPS Damage Assessment Team (DAT) clearance:

Prior to that, all Damage Assessment Team (DAT) assessment of OBSS (Orbiter Boom Sensor) data and FD3 RPM (R-bar Pitch Maneuver) photography from the ISS confirmed that Endeavour’s two ET umbilical well doors were closed, that there were no upper flight surface protrusion of any kind, and that six of the seven lower damage sites had been cleared without the need for a Focused Inspection (FI).

Following the FI of the three-tile damage location, lovingly dubbed “The Maine” damage because of its remarkable resemblance to the U.S. state of Maine, a detailed characterization of the damage was compiled.

From this, it was confirmed that all tile material was still intact in all areas with no exposed filler bar material; no cracks were identified; the dark area of TPS as seen from RPM imagery was an area of abrupt damage depth change – as expected; all thermal stress assessments revealed no structural overtemp issues for reentry; a “small area” of TPS bondline overtemp would occur during reentry but is acceptable for reentry due to its distribution over three tiles; all TPS and structural margins were well within safety limits for reentry.

Thus, the TPS DAT unanimously recommended clearing Endeavour’s entire Thermal Protection System for reentry in emergency return cases and for nominal EOM (End of Mission) reentry pending the completion of the Docked Late Inspection (DLI).

Click here for the previous five STS-134 DAT TPS Status Articles: http://www.nasaspaceflight.com/tag/tps/

Detailed Focused Inspection damage site clearance overview:

Following the detailed and fascinating Focused Inspection of the “Maine” damage site, photographic and laser measurement data revealed that the damage was 0.89 inches in depth, +/-0.04 inches, and remained above the filler bar.

This means that tile margin exists in all areas of the damage cavity, or what the post-FI inspection presentation – available for download on L2 – classed as a “dense layer.” (View Anaglyph slide left with 3D glasses).

In all, the damage location is 0.89 inches in depth, 2.95 inches in length, and 2.43 inches in width.

In fact, the TPS clearance presentation notes that there are very few areas of missing material and no cracks radiating outward or downward from the main damage site.

Furthermore, views of the damage location obtained from the OBSS’s Laser Dynamic Range Imager (LDRI) confirmed that sections – but not all – of some AMES gap fillers were missing, indicating that the “Impactor had enough energy to damage multi-layer AMES gap filler.”

However, it appears that the AMES gap fillers had an unintended positive consequence as “Adjacent tile damage size [was] reduced by the presence of AMES gap filler.”

In comparison to a similar tile damage event on the STS-118/Endeavour mission, the STS-118 damage was 3.48″ x 2.31″ x 1.12″, was located at Xo 1260 Yo 123 Zo 269, and carried a tile depth of 1.12 inches.

STS-134/Endeavour’s damage was 3.22″ x 2.49″, was located at Xo 1243 Yo 106 Zo 267, and was located on a tile with a thickness of 1.04 inches.

Based on analysis conducted during the STS-118 mission, that mission’s damage was found, based on on-orbit information analysis, to have a Mach 16.7 Boundary Layer Transition (BLT) time. STS-134′s damage is predicted to have a Mach 12 (nominal) BLT time.

All STS-134 FI damage was further found to have baseline aeroheating, BLT, Boundary Layer Wedge, Cavity Heating, Thermal Analysis, Tile Stress, and Stress indicators in Model Category “A” – indicating that “Baselined model used within model limitations or intended use.”

A maximum temperature calculation for the FI damage locations was created, and “Due to flow orientation, assessment [was] performed in both the aligned and cross-flow orientations of the simplified cavity,” notes the TPS DAT clearance overview presentation.

Based on these parameters, a maximum structural temperature of 219-degrees F and a maximum RTV bondline local temperature of 1,194-degrees F are expected during entry on Wednesday morning. The maximum structural temperature allowed is 350-degrees F, leaving high structural margin.

Nonetheless, the total RTV bondline temperature does exceed nominal limits; however, RTV bondline temperature “over 625°F is limited to 6 inches squared distributed over 3 tiles.” For the damage site on STS-134/Endeavour, the aligned flow max temperature is predicted at a modeled rate of 5.75 inches squared with an actual in-flight temp on the critical tile of 4.06 inches squared – both meeting the design requirements.

Likewise, the cross flow max temperature is predicted at a modeled rate of 6.19 inches squared with an actual in-flight temp on the critical tile expected at 3.98 inches squared – again, well within the design criteria.

Therefore, all structural margins remain positive for STS-134 and the OPO (Orbiter Project Office) and DAT unanimously recommended clearing Endeavour’s TPS for entry.

“DAT resolved issues associated with difficulties modeling complex damage, and is in good posture to support STS-135,” notes the overview presentation.

Following this assessment, Endeavour’s TPS was cleared for entry pending the results of the Docked Late Inspection, or DLI.

After completing the DLI, the DAT identified 162 regions of interest (ROI) on the vehicle’s Reinforced Carbon-Carbon wing leading edge panels.

Across the spectrum of flights from STS-121 to STS-133 – excluding STS-114 (no Late Inspection on that mission), STS-124, and STS-132 – the average ROI count was 151, with a high ROI count of 771 on STS-124 (results not included in the average since the mission could not conduct a standard post-launch OBSS inspection) and a low count on STS-133 of 52.

These ROIs were quickly cleared by the DAT and Endeavour’s TPS unanimously and formally cleared for entry.

STS-134 Specific Articles: http://www.nasaspaceflight.com/tag/sts-134/

But most importantly, none of this detailed assessment of the “Maine” damage location would have been possible without Endeavour’s trusty OBSS. To this end, NASA created a special presentation on the life and times of the OBSSs over their six years of service to the Space Shuttle Program – from inception, to creation, to first flight, to significant achievements in space.

And from NASA and the OBSS team to the OBSS now permanently affixed to the International Space Station, these parting words reflect the importance of all three booms in their service to the Shuttle program and its courageous astronauts: “As Shuttle says ‘goodbye’ to the OBSS and ‘thank you’ to the sensors for their outstanding service, Station says ‘welcome’ to the EIBA – Enhanced ISS Boom Assembly.

“May the EIBA serve the ISS as well as the OBSS has served Shuttle.

“Farewell, OBSS, and job well done!”

Flight Day 16 – also known as EOM-1 (End Of Mission minus one day) successfully completed the checkout of Endeavour’s Flight Control Surfaces – via the use of APU-1 – prior to a full firing of Endeavour’s Reaction Control System (RCS) thrusters.

Communication checks with ground stations were also deemed to be succesful, which were carried out after entry and landing simulations via the use of a laptop and flight stick.

The crew also recorded – after mission the window in communications – a tribute video for Endeavour, which will be edited and played back sometime on Tuesday.

Next article will be published early on Tuesday.

(Images via L2 presentations, images and content). Extensive coverage is being provided on the news site, forum and L2 special sections – the latter of which is the world’s best front row seat to Shuttle missions. With specific and extensive flight day coverage, from interactive “one stop” FD live coverage in the open forum, to internal documentation, photos, videos and content in the specific L2 FD areas).

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1. Endeavour and her SCA piggyback ride arrive in Louisiana, via JSC flyoverThe Shuttle Carrier Aircraft (SCA) and Endeavour departed from Edwards...

STS-134 Undocking:

Following a pre-departure reconfiguration of one of the EMU (Spacesuits) to be left on Station for use at a later date by Expedition 28 flight engineer Ron Garan, work on the Carbon Dioxide Removal Assembly (CDRA), and the final transfers of equipment and supplies between Endeavour and the ISS, the STS-134 crew bid farewell to the ISS crew on Flight Day 14.

“We’ve had a very successful mission, a really good 10 days or so,” noted STS-134 commander Mark Kelly. “Looking forward to getting home and giving the ISS crew some peace and quiet.”

Commander Kelly’s best wishes were responded to by Russian Commander Andrei Borisenko, who wished the crew a “soft landing”, a possible internal joke to how the orbiters are much easier on the crews when compared to the Soyuz during re-entry and landing.

In the end, hatches between the two spacecraft were open for joint crew operations for a total of 10 days, 23 hours, 45 minutes. Hatches closed between Endeavour and the space station at 6:23am Central – 12 days, 22 hours, 27 minutes into the mission.

Following leak checks and the checkout of systems to be used for the Flight Day 15′s undocking, Endeavour’s crew went into their final sleep period whilst still being attached to the orbital outpost.

STS-134 Specific Articles: http://www.nasaspaceflight.com/tag/sts-134/

In preparation for 22:55 Central undocking, the ISS’ Solar Alpha Rotary Joints (SARJ) were locked, and the four giant arrays were  feathered, so as to protect the arrays from plume impingement as Endeavour pulsed her Reaction Control System (RCS) jets to move gently away from the Station.

The arrays on both the European ATV-2 (Automated Transfer Vehicle) and those on the Russian segment, were also be feathered for the same reason.

Easing away from the Station for a period of nearly 30 minutes, Endeavour was commanded through a stunning flyaround of the ISS, taking over one hour, prior to the debut of the STORRM (Sensor Test for Orion Relative Navigation Risk Mitigation) DTO.

STORRM Overview:

The STORRM flight test on STS-134 is demonstrating the first US-developed, highly-reliable navigation sensor – the Vision Navigation Sensor (VNS) – designed expressly for rendezvous and docking for future American spacecraft.

Utilizing state-of-the-art laser-based sensor technology necessary for accurate, robust, and safe navigation between the docking vehicles, the system incorporates advanced LiDAR (Light Detection And Ranging) technology that can determine  shapes, intensity and distance to objects from as far away as three miles or as close as five feet.

Its applications are wide-ranging, providing the required hazard avoidance data required for safe landing on asteroids, the moon, and Mars. The sensing technology may also improve a variety of Earth-bound applications such as climate and environmental observations, robotic maneuvering, topographical surveillance, and hazard avoidance systems for cars or aircraft.

Lockheed Martin and Ball Aerospace independently invested several million dollars in developing and building the space-qualified VNS being flown on STORRM, originally designed with the Orion crew exploration vehicle in mind.

While Orion continues to be developed, amid much fanfare for a name-change to the Multi Purpose Crew Vehicle (MPCV), its main launch vehicle companion – the Space Launch System (SLS) – is potentially just days away from transitioning from study to development.

It is hoped specific missions will also be named soon, which will likely utilize the STORRM technologies under investigation during Endeavour’s DTO.

Preparations for this full-up test began in April of last year, when Orion retro-reflectors were installed on the ISS visual docking target during STS-131.

“STORRM DTO #703 Docking Target Installation: Background: Relative Navigation sensors for Orion vehicle require special ‘reflectors’ on the PMA-2 docking target,” explained STS-131 Flight Readiness Review (FRR) documentation on L2.

“DTO #703 (post-undocking re-rendezvous) slated to fly on STS-134/ULF6. STS-131/19A will fly and transfer STORRM DTO docking target reflectors to ISS. ISS crew will install reflectors and STS-131 crew will take close-out photographs of docking target after hatch closure (prior to undock).”

Opening STORRM’s role with STS-134, a large amount of data was gathered during Flight Day 3′s rendezvous and docking with the ISS.

“Sensor Test for Orion Relative-Navigation Risk Mitigation (STORRM) Development Test Objective (DTO) performance during rendezvous and docking was excellent. STORRM collected 232 GB of Docking Camera data and 108 GB of Vision Navigation Sensor (VNS) data,” noted an overview (L2) to the Mission Management Team (MMT).

“The key technology for STORRM, the VNS, performed as expected in terms of moding, laser firing, and imaging the ISS. The team was able to see images from the docking camera in real-time as well.”

During the downloading of the VNS data via the Ku band system, a problem relating to the STORRM Local Area Network (LAN) connection at the access point of the hardware was noted. However, this only caused a slight delay to the data reaching the ground.

“STORRM DTO exhibited an Ethernet problem during the VNS data retrieval from Data Recorder Unit (DRU) 1 which may be caused by connections; the STORRM ground controllers did not receive all of the files to be down linked,” added a later MMT overview.

“The data transmission halted several times with duration of half hour to an hour each. There (was a need) for some reconfiguration to retrieve the rest of the files, prior to power down DRU1.”

Ready for action after undocking, a series of presentations and videos (L2) overviewed the role of the STORRM hardware.

“Undock: Sensors are powered on 30 minutes prior to physical separation. As Orbiter “backs away”, sensor settings are applied as a function of range to ISS. Orbiter remains in “Target Track” when not performing translational burns,” noted one presentation.

For undocking, TV Monitors – the displays on the Payload General Support Computer (PGSC) – showed Range Bin Transitions and VNS and Docking Camera (DC) images – however, the latter was noted to be out of action for the undocking per the Mission Status Briefing on Sunday.

“TV Monitors will show STORRM Software Application sending commands to sensors as a function of range to ISS,” the presentation noted. “TV Monitors will also show VNS and DC images of STORRM reflectors and the ISS docking target.”

To accomplish the STORRM DTO, just after undocking from the ISS, Endeavour’s Commander and Pilot performed the standard back out and ISS Flyaround maneuvers through the Sep 1 burn.

However, in terms of nominal Shuttle/ISS undockings, Flyarounds, and separations, this is where the similarity for STS-134 ended.

Endeavour’s Sep burns 2 and 3 (including all the mandatory STORRM burns) were redesigned to facilitate a mini re-rendezvous with the ISS to “accomplish the STORRM re-rendezvous objectives” before completing the flyout of Endeavour to a point “in front” of the ISS in terms of the vehicles’ orbital trajectories and relative positions.

The additional time taken to perform the STORRM DTO was built into the mission time, aided by the lack of Late Inspections – which normally take up to five hours of the flight day. The inspections were completed late into the docked mission, due to the requirement to leave the Orbiter Boom Sensor System (OBSS) on Station to become the Integrated Boom Assembly (IBA).

Once Endeavour is back in her Orbiter Processing Facility (OPF) during post flight deserving, the entire raw data will be collated for evaluation.

“VNS: Perform calculations on raw data (range and intensity measurements) to determine geometric centroids to reflective elements, range and bearing to target, and pose,” added another presentation on the forward plan.

“Compare VNS measurements with Orbiter sensors and relative best estimated trajectories. Investigate any anomalous data collected. Characterize measurements. Update ground models as appropriate. Incorporate data into Orion simulations to assess filter performance.

“DC: Convert raw data to images (if any are available, per failure). Perform assessments of images for piloting cues. Exposure/gain control algorithm performance. Perform assessments of images for use in star tracking. Perform Natural Feature Image Recognition analysis. Investigate any anomalous data collected. Update ground models as appropriate.”

As with a number of DTOs being carried out by the orbiters, NASA managers have ensured their legacy is not just historical, but one where future spacecraft will directly benefit from their vast experience.

(Images via L2 presentations, videos and images – plus nasa.gov images stitched by Ron Smith III). Extensive coverage is being provided on the news site, forum and L2 special sections – the latter of which is the world’s best front row seat to Shuttle missions. With specific and extensive flight day coverage, from interactive “one stop” FD live coverage in the open forum, to internal documentation, photos, videos and content in the specific L2 FD areas).

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