Flight Readiness Review:

NASA’s FRR process is a full review of every aspect of an upcoming mission, including safety reviews, technical readiness reviews, flight hardware reviews, and many other hardware, software, system and procedural related reviews. As was proven during the Space Shuttle Program, FRRs are a very effective tool to ensure that every system is as ready as it possibly can be to ensure safe and successful completion of an upcoming mission.

As was typical of the conclusion of Shuttle-era FRRs, a formal launch date is usually posted. However, the launch of SpaceX’s cargo-laden Dragon capsule – atop a Falcon 9 booster from Cape Canaveral Air Force Station (CCAFS) Launch Complex-40 (LC-40) – is tracking April 30, but that is pending the resolution of a couple of open items that require additional testing relating to software on the ISS side.

As of this time, April 30 is still the target for what will become a date of historical significance with the occurrence of the first ever launch of a privately-owned rocket and spacecraft to the ISS.

Monday’s FRR also carries some historical significance, as the first launch of a private spacecraft – widely touted as the “successor” to the Space Shuttle – has been approved on the very same day that the first Space Shuttle orbiter to head off into retirement spent her last full day at the Kennedy Space Center, with the responsibility for ISS support now reluctantly handed off from the seasoned Space Shuttle orbiters to their eager young commercial siblings.

Dragon mission overview:

The long-anticipated combined COTS-2/COTS-3 (C2/C3), also known as Demo-2/Demo-3 (D2/D3) and officially noted as the SpX-D mission, will be the first visit of SpaceX’s Dragon spacecraft to the ISS, with major vehicle modifications over the only previous Dragon flight in December 2010 being rendezvous and berthing systems, and spacecraft trunk complete with solar arrays and radiators.

Click here for other Dragon News Articles: http://www.nasaspaceflight.com/tag/dragon/

Following launch on April 30, Flight Day-1 (FD-1) and FD-2 will see Dragon perform the far field phasing portion of its mission, during which time checkouts of Dragon’s Absolute GPS (AGPS), free drift and abort capabilities will be performed.  FD-3 will see Dragon perform a 2.5km fly-under of the ISS to test Dragon’s Ultra High Frequency (UHF) communication via the COTS UHF Communication Unit (CUCU) on ISS.

FD-3 will also see other tests being performed on Dragon, such as Dragon command ability by the ISS crew (strobe light switch on) via the Crew Command Panel (CCP) connected to the CUCU, and a Relative GPS (RGPS) checkout between Dragon and ISS. At the end of FD-3, the ISS Mission Management Team (IMMT) will meet with SpaceX managers  to determine whether C2 mission objectives have been successfully satisfied.

Should C2 objectives be met, the IMMT will give a go-ahead for FD-4′s attempt at C3 objectives, which include a full Dragon rendezvous with the ISS, flying to within 30m of the station in order to be grappled by the Space Station Remote Manipulator System (SSRMS) and berthed (not docked) to the Node 2 Nadir port by Expedition 31 astronauts Don Pettit of NASA and André Kuipers of ESA, working from the ISS’ Cupola observation/robotics station.

Although free-flyer captures have been performed previously on ISS during the Japanese HTV-1 and HTV-2 missions, the Dragon capture may be slightly more challenging.

“There’s unknowns with these new vehicles [because] they haven’t been there [ISS] before, and from the past experience we know HTV has been very very solid, which made it relatively easy to capture,” explained NASA astronaut Joe Acaba – who will arrive at the ISS aboard Soyuz TMA-04M roughly two weeks after Dragon’s arrival – to NASASpaceflight.com’s Philip Sloss during a pre-flight interview.

“ These others [commercial vehicles], they’re a little bit lighter with some bigger thrusters, so there may be more motion that we might see, so they may be a little bit more challenging.”

Following the opening of the ISS Node 2 Nadir and Dragon Common Berthing Mechanism (CBM) hatches and mating of all power/air hoses and ventilation between ISS and Dragon on FD-5, Dragon will enjoy a roughly two and a half week stay at the ISS, during which time Dragon’s non-essential cargo will be transferred to the station and trash/return items loaded in its place.

After the completion of the cargo transfers, Dragon will be unberthed from the ISS and released by the SSRMS for a re-entry and splashdown off the coast of California – thus regaining some marginal down-mass capability for the ISS Program that retired along with the Space Shuttles last year.

(A more in-depth overview of the C2/C3 mission will be covered in a separate article on NASASpaceflight.com.)

ISS ready to receive Dragon:

Dragon’s destination, the ISS, is now fully ready to receive its first commercial guest, following a SpX-D Stage Operations Readiness Review (SORR) preformed on 5th April, the presentation for which, along with other SORR presentations and an impressive set of exclusive ISS on-orbit status notes and images, are available to view and download on L2 (L2 Link).

With hardware and software transitions successfully completed earlier this year, and ISS robotic assets prepared last week for Dragon’s arrival, only a few issues relevant to the Dragon mission were noted in the SORR presentations, all of them minor and classed as low risk, and with all bar one being cleared as having no impact to SpX-D flight operations.

The only issue listed as having a “potential” issue to SpX-D flight ops was the recent 2A Beta Gimbal Assembly (BGA) pointing command issue and subsequent transaction errors. BGAs provide beta rotation capability to allow the Solar Array Wings (SAWs) to track the sun.

“Controllers saw a suppressed caution for an invalid BGA 2A Pointing Control Command. At the same time transaction errors were seen on the UB-PVA-24-1 bus and a channel swap from A to B. Data shows the transaction errors were due to no response from RTs (Relay Terminals) outboard of the BMRRM (Bearing Motor Roll Ring Module) which points to a potential issue with the signal ring in the BMRRM.”

The SORR presentation noted: “Transaction errors are consistent with hypothetical short due to FOD (Foreign Object Debris) in the signal roll ring of the BMRMM. There is one spare BMRMM stowed on-orbit. EVA procedures to replace a faulty BMMRMM are mature”.

Over the next few weeks, numerous similar transaction errors continued to occur on Channel B, causing swap overs to Channel A and subsequent swap backs to Channel B. From reviewing data, flight controllers were able to determine that: “All 5 of the most recent sets of transaction errors have now occurred between BGA angles of 27 degrees – 30 degrees”.

After remaining on Channel A for a few days in order to prevent further transaction errors on Channel B, a meeting of the Failure Investigation Team (FIT) determined that the forward plan, which is currently in effect, was to switch back to Channel B for 40 days to gather data on bus performance. “The automated response to swap bus channels in response to the loss of data connectivity will be inhibited to gather information on how long the data dropouts last”, continued the notes.

While the 2A BGA transaction errors was the only issue noted as having a potential impact on the SpX-D mission – although the issue is still classed as low risk and acceptable to flight, despite being ongoing – there were other notable issues that relate to the SpX-D mission that were cleared as being no impact.

The Cupola, the seven-windowed observation module from where the SSRMS will be controlled during Dragon’s capture, offers increased situational awareness over simple video monitors inside the ISS. However, the means by which this is achieved – 360 degree windows – have been having some minor issues of their own of late.

“Cupola Window 6 Temperature Divergence – Specialists have been tracking a divergence between the two temperature sensors on Cupola Window 6. This signature has been seen in the past on Window 5 when a laptop was placed near one of the temp sensors,” stated L2 ISS on-orbit status notes. “The crew was asked about Cupola configuration, but there were no laptops or other heat generating equipment near Window 6″.

 Using a temperature probe, the crew took readings near the window temperature sensors.  Based on those readings, no noteworthy divergence between the windows was detected, however there was a noticeable difference between the temperature sensor reading and manual reading for Window 6 RTD (Resistance Temperature Device) 2.

“During Passive Thermal Control System’s team Cupola Window temperature scans they noticed that Cupola Window 6 exceeded its upper temperature limit of 100 degrees F (37.3 degrees C) at 38.3 deg C for 13 minutes,” added the notes. ”Per Flight Rules, if any Cupola window exceeds 36.7 degrees C for more than 5 minutes, the shutter must be closed.

“Exceeding the upper limit is a concern for the Cupola window seal. Engineering is assessing the temperature violation and its duration. The window shutter has been requested to remain closed until this assessment is complete. Upper Cupola Window temperatures can be managed by closing the window shutters when not in use.”

Notes the following day mentioned that temperature exceedance issues had also occurred on Cupola Window 1: “The Cupola Window 1 (Port) temperature exceeded the 36.7°C watch limit and maxed out at 39.3°C. It was above the limit for approximately 7 minutes. The flight rule only allows for <5 minutes above the 36.7°C limit.”

“Per the Flight Rules, the ground requested the crew to close the Window 1 shutter and the temperature began to drop.  The concern is the integrity of the seals around the window. This small exceedance is not considered a hazard, but the elevated temperatures are under investigation for potential causes and prevention.”

As for probable causes, the SORR presentation noted: “On 25/03/12, window scratch panes (with heaters) were R&R for ATV-3 antenna photography. Leading theory is partial delamination of RTD 2 is possible; may have exacerbated during scratch pane removal (not easily accessible for inspection)”.

While the investigation into the window temperature issues is still ongoing, since the exceedance values are low and an adequate mitigation (closing the shutters) is available, this allowed the issue to be classed as being no risk to the SpX-D flight.

Another minor issue was noted which related to the Space Integrated GPS/Inertial Navigation System (SIGI), which will be utilised by Dragon during Relative GPS (RGPS) communication with the ISS. There are two SIGIs aboard the ISS, although one had been showing signs of ageing.

“SIGI-1 is near end of its 10 year life and an unused internal gyroscope has caused multiple failures recently. All were recovered by power cycles. The SpaceX LCC (Launch Commit Criteria) requires 2 SIGIs, after that only 1 is required for rendezvous and capture,” stated the SORR presentation. 

“Dragon will abort during rendezvous if data is not available from an active SIGI within 5 or 10 minutes (depending on proximity to ISS). Following a power cycle, an ISS SIGI takes a minimum of 30 minutes to recover functionality”.

“SpaceX and ON prefer to R&R (Remove & Replace) SIGI-1 to increase the likelihood of mission success. There are 2 spares on orbit and 4 on the ground. R&R requires ~7 hours crew time, requires repeat of the 12 channel checkout, and 3 weeks run time prior to LCC. ON recommended R&R of SIGI-1 to minimize the likelihood that degraded internal gyroscope will cause it to fail during Dragon rendezvous.”

As continued by L2 ISS on-orbit status notes: “On April 4, the SIGI-1 was R&Rd. It was placed in first priority for both ISS State and Attitude on April 6. Yesterday, ground controllers completed the final checkout for SpaceX operations – a 12 channel test.  The data dump for the 12-channel test is still under evaluation, however the test was nominal”.

As such, the SIGI issue is now considered resolved and is classed as no impact to the SpX-D mission.

Only one other minor issue pertains to the SpX-D mission, which is a slightly open protective petal on the Node 2 Nadir (N2N) Active Common Berthing Mechanism (ACBM) port to which Dragon will attach. In addition to internally removable Center Disk Covers (CDCs), ACBM petals provide protection for the ACBM – specifically the berthing ring – that would otherwise be exposed to space.

The four petals (one for each quadrant of the berthing ring) on each vacuum-exposed ACBM on the ISS are designed to open and close (like a flower petal – hence their name) remotely when commanded in order to expose the berthing ring. If a petal were to become stuck open, it would leave the ACBM berthing ring open to MMOD (Micro Meteoroid Orbital Debris) strikes, and if a petal were to become stuck closed, it would preclude a berthing from occurring.

As stated by the SORR presentation: “During an SSRMS pre-motion survey, the N2N ACBM Petal #1 (Starboard-Aft) appeared to be slightly open, although mostly closed. This condition was not noticed during a recent N2N CBM survey and checkout, due to the camera angles used at that time”.

“Per photo review, the petal #1 position may have been in this configuration since STS-123/Flight 1J/A (March 2008), when the Petal #1 launch restraints were released. Petal #1 is not believed to be warped and both sides appear to be the same displacement above adjacent petal covers. Petal #1 has been through approximately 15 successful open/close cycles with no issues.”

“Status: A prep for mate (exercising the latches and opening the petals) will be performed approximately 40 hours prior to berthing. After the SpaceX Dragon demo is berthed, OSO (Operations Support Officer) will ask if the crew could inspect Latch #1 to see if it is different from the others.”

Thus, with all ISS issues determined to be low risk and of little or no impact to the SpX-D flight, the SORR concluded that: “The ISS MER (Mission Evaluation Room) is Go for SpX Capture, Attached Ops, SpX Release and Stage operations”.

(Images: L2′s SpaceX Dragon C2/C3 Mission Special Section – Containing presentations, videos, images, interactive high level updates and more, with additional images via NASA and SpaceX). 

(Click here: http://www.nasaspaceflight.com/l2/ - to view how you can access the best space flight content on the entire internet).

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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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Images: Via L2 content, driven by L2′s fast exapanding SLS specific L2 section, which includes, presentations, videos, graphics and internal updates on the SLS and HLV, available on no other site. Other images via NASA.)

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STS-135 Latest:

Atlantis will carry the Multi-Purpose Logistics Module (MPLM) Raffaello and a Lightweight Multi-Purpose Carrier (LMC) to the International Space Station for a 12 days baseline mission, as much as Station managers have requested an additional docked day in the timeline.

Such a decision will be taken during the mission, based on the crew’s workload, progress on the timeline and Atlantis’ consumables status, given she is slightly handicapped – when compared to her two sisters – due to the lack of a Station-to-Shuttle Power Transfer System (SSPTS).

“The SORR (Stage Operations Readiness Review was held, with a “GO” for launch. Some small changes to stowage were identified, which will happen after the L-10 Bench Review,” noted Flight Operations & Integration (NASA/JSC) via the latest Shuttle Standup/Integration report (L2).

“The team wants to fly a major constituents analyzer (MCA) up, and make a few changes. ISS Program still wants to add a +1 day to the mission.”

Other late items of interest ranged from the results from the recent Tanking Test on Atlantis’ External Tank (ET-138), through to a review into the flammability risk with the orbiter’s oxygen system – both requiring updates from the main SSP (Space Shuttle Program) FRR.

“There was some discussion at the SSP FRR about oxygen system flammability. After a thorough review of the systems in the orbiter, the test results indicate that there is no risk for this environment,” noted the Orbiter Project Office (OPO) on the Standup report. “It is a risk that requires an operating pressure of 4,000 psi, and the maximum in the orbiter environment system is just over 1,000 psi.”

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

The lesser of two issues noted during the Tanking Test – relating to an open indication on ET-138′s LO2 17 inch disconnect valve – was also cleared, following the replacement of an associated connector.

“On the Orbiter anomaly from the tanking test, the LO2 17 inch disconnect “B” open indication did not come on. The connector and some wire have been R&R’d (Removed and Replaced),” added the Orbiter Project.

“The replacement has shown good results ever since. There has been more manipulation, and the retest looks good. The faulty connector has been sent to NSLD (NASA Shuttle Logistics Depot) to see if they can find the source of the original problem.”

The main issue observed during the Tanking Test was the leak detected in the Main Fuel Valve (MFV) on Space Shuttle Main Engine 3 (SSME-3), which would have caused a scrub on launch day.

The replacement completed successful retests over the weekend, involving a Flight Readiness Test (FRT) and a Helium signature test – the latter via the use of a mass spectrometer, which sniffed for any tiny leakages from the system. None were found.

“IPR 0049 SSME 3 Main Fuel Valve (MFV) R&R is essentially complete: Heat shield installation was completed. MFV retest, includes SSME 3 FRT and He Signature test, was successfully completed over the weekend,” added the NASA Test Director (NTD) update (L2). “The GH2 blank off plate was removed.”

The primary role of the Tanking Test was to provide a cryogenic and pressurized test of the strength of ET-138′s stringers, support beams which are located on the intertank.

The call for the test was due to the close relation of ET-138 with STS-133′s ET-137, which suffered from cracks during the opening launch attempt, which was scrubbed due to a leak on its Ground Umbilical Carrier Plate (GUCP).

Radius blocks – the main mitigation procedure, designed out of the STS-133 incident – once again proved they are capable of providing the additional strength that may be required by the stringers during tanking.

A week’s worth of inspections, via the use of both X-Ray and Backscatter equipment, checked the main areas of concern, the LO2 and LH2 flange areas of the intertank, with the results showing no issues were found.

“ET NDE (Non Destructive Evaluations) operations: Review of the X-rays on the LH2 flange is complete with no problems detected,” noted the NTD update, confirming both the LO2 and LH2 flange areas showed no signs of underlying cracks on the stringers. “ET NDE X-ray operations are complete.”

“The team pulled together the data on NDE, and has made a great effort,” added the ET Project on the Standup report. “When the data needed is received, it will be coupled with the update for the waiver and will submit it and start taking care of the CoFR (Certification Of Flight Readiness) statement.”

With the Agency FRR approval, engineers out at Pad 39A will continue with their preparations for the S0007 Launch Countdown, with final replenishment of the LH2 and LOX spheres at the pad complex in work, in tandem with closeouts on the orbiter, final ordnance installation and preps for the pressurization of Atlantis’ Main Propulsion System (MPS).

“LH2 storage tank replenishment was completed Friday with two waves of tankers off loaded. LOX storage tank replenishment is in work with 4 waves scheduled to be off loaded,” the NTD continued. “S1287 Orbiter Aft closeouts are in work and will continue all week.

“Preps for V1103 EMU (Spacesuit) functional will be performed, with testing scheduled for tomorrow (Wednesday). S5009 Final Ordnance Installation will be performed tonight (Tuesday). S0071 Hyper/MPS press is scheduled to begin on Wednesday.”

ISS Late Conjunction:

Contingency actions were taken onboard the ISS on Tuesday, due to what is known as a late conjunction in the red box, meaning a piece of space debris was tracking to make a close approach to the Station, and noticed too late for the ISS to make a Debris Avoidance Maneuver (DAM).

The debris – which remains unidentified – made its its closest approach to the station at 9:08 am CDT, with the threat passing by as close as 820 feet (250 meters) of the station.

As a contingency, Expedition 28 Commander Andrey Borisenko, and Flight Engineers Ron Garan, and Alexander Samokutyaev took shelter in their Soyuz TMA-21 spacecraft, docked to the station’s Poisk module. Flight Engineers Sergei Volkov, Mike Fossum and Satoshi Furukawa took shelter in their Soyuz TMA-02M spacecraft, docked to the Rassvet module.

The crew members climbed into their spacecraft, which remain docked to the station for the duration of their stays for use as return vehicles or emergency lifeboats, about 20 minutes before the time of closest approach. They were back inside the station, resuming normal duties, within about 15 minutes of the all-clear signal.

This was only the second time that a space station crew had been required to take shelter in their Soyuz spacecraft, the first time was March 12, 2009, after a a “yo weight” – which was originally part of a Delta PAM-D stage used to launch GPS 37 in 1993, also known as Object “25090 PAM-D” – missed the Station.

(Images: Via Larry Sullivan MaxQ Entertainment/NASASpaceflight.com and L2 content. Further articles on STS-135′s status in work, driven by L2′s fast expanding STS-135 Special Section which is already into the FRR content and live flow coverage, plus more.

(As with all recent missions, L2 is providing full exclusive level flow and mission coverage, available no where else on the internet. To join L2, click here: http://www.nasaspaceflight.com/l2/)

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STS-134 Latest:

Endeavour already has her game face on at Pad 39A, with no Interim Problem Reports (IPRs) of note – at least from her own hardware perspective – for some time now.

The lack of issues has also aided what continues to be a nominal pad flow, which has seen the completion of ordnance installation and the beginning of preparations for the pressurization of the Main Propulsion System (MPS).

“OV-105/SRB BI-145/RSRM 113/ET-122 (Pad-A): LOX storage tank sampling was completed last Friday. ET Camera battery charging was also completed Friday. S0007, Launch countdown preps continue,” noted the NASA Test Director (NTD) report (L2).

“S5009, Final ordnance installation is complete. Range safety system testing was completed. Orbiter/SRB PIC tests and ignition S&A rotation are in work at the time of this writing. It is anticipated that the pad should be re-opened at approximately 0730 EST this morning. S0071 Hyper/MPS pressurization preps call to stations is scheduled for 1600 EST tomorrow. GO2 recharge is scheduled for Wednesday.”

Endeavour’s mission continues to be refined, with one recent memo outlining the current plan for the working mission timeline, one which holds the option of being extended past the 14 day flight into a maximum 16 day primary mission.

“To avoid any confusion, we have removed all what-if timelines, and have left only the official 14+2+2 Flight Plan for you to peruse,” noted one MOD memo (L2). “Once the calm settles in, we will work to re-post the +1 and +2 versions. Until it all changes again.”

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

Also mentioned was the latest trajectory data, utilizing the middle ground of 15+1+2 as the baseline. The data relates to Endeavour’s rendezvous with the International Space Station (ISS) and departure – the latter of which will include the STORRM (Sensor Test for Orion Rel-Nav Risk Mitigation) Detailed Test Objective (DTO).

Designed to collect detailed data during rendezvous, proximity ops, and (un)docking, Endeavour’s crew will document, via photographs, all STORRM targets for photogrammetry objectives following Shuttle/ISS hatch opening and prior to Shuttle/ISS hatch closure.

“This trajectory data was generated using the L-25 days ISS vector. It includes a 15+1+2 mission duration and an ISS phasing strategy which results in a STS-134 rendezvous altitude of 187 nm,” added the memo. “The Orbiter ephemeris includes a FD14 midnight undock, followed by a 27 min Vbar separation, a 46 min fly around, a 1.5 fps SEP1 burn (3 fps effective) and STORRM DTO maneuvers starting with SEP2.”

To accomplish the STORRM DTO, just after undocking from the ISS, Endeavour’s Commander and Pilot will perform 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 will end.

Endeavour’s Sep burns 2 and 3 (including all the mandatory STORRM burns) have been 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.

Storm Damage Evaluations:

It was a different type of Storm which gained attention at the latest Program Requirements Control Board (PRCB) meeting – ahead of its subsequent promotion to the Flight Readiness Review – with the recent severe storm weather damage evaluated and found to be of no concern ahead of Endeavour’s final launch.

A large amount of concern was forthcoming via four evaluation presentations (all available on L2), which reviewed the lightning strikes observed near the pad. Thankfully, none were classed as direct strikes, via the array of instrumentation and protection which is in-situ at the pad complex.

“One Lightning Strike Determined to be within 0.45NM, but not within 0.30NM. GSE (Ground Support Equipment) Walkdowns for Lightning. GSE/Facility Lightning Strike Walkdowns – were performed and Complete for 30 March 2011 Strikes,” noted one of the presentations.

“31 March Lightning Strike confirmed (by OTV – TV cameras) to be at Sea, away from LC-39. Did not Trigger 2nd Run of Seq 12, but Walkdowns occurred after both Events. No Damage Found.”

“Lighting assessment: Lightning was detected in the vicinity of KSC LC-39 on March 30 and 31, 2011. Concurs with the April 5 joint ERB conclusions that there are no issues, and retests are not recommended for SSP systems due to that lightning.”

High winds from the storms were also evaluated, this time focusing on the associated hardware with the Ground Umbilical Carrier Plate (GUCP). The concern relates to the wind loads on the vent arm potentially translating on to the GUCP, causing a potential misalignment to form – something which engineers would wish to avoid given the recent leaks from the hardware, including STS-133′s ET-137.

“Winds on 3-30-2011 at Pad A were recorded to 78.7-knot from the Southwest (2200-2600). The following concerns due to the high winds will addressed:. Concern 1: Did the high winds move the vehicle outside of the tested excursions? Concern 2: Are the loads induced into the Umbilical including 7-Inch QD/GUCP by the high winds a concern?”

Thankfully, the evaluations resulted in positive results, as the analysis showed the 78.7-knot gust was within tested limits, noting the Haunch Pivot Arm angle was within tested limits and that the axial load into 7-inch QD, GUCP and Pyrotechnic bolt were all within the required parameters.

“Analysis shows the 78.7-Knot gust recorded is well within the tested system limits. Pivot Arm and Vent Line angles are less than tested excursions. Pivot Arm angle controls axial load in Vent Line. Calculations show a 5.25 safety factor at the 7-In/GUCP Interface,” added the GUCP specific presentation.

“The peak gust was 30 degrees perpendicular to vent line centerline (perpendicular wind used in calculation). Inter-tank access arm helps protect the vent line from winds (not used in calculations). 2 g’s dynamic factor very conservative.

“Pending completion of nominal planned work, the GH2 vent line including 7-in QD/GUCP are ready to support STS-134 launch countdown.”

The final evaluation related to the hail damage to the top of ET-122, which only resulted in minor Thermal Protection System (TPS) damage, well within acceptable limits.

“Assessment: External Tank assessment of 03/30-03/31 severe weather event and affect on ET-122,” noted the Lockheed Martin presentation on the tank. “Actions Taken: Performed visual and hands on inspection of ET hardware. Impacts primarily on the -Y / -Z quadrant. No indications / impacts observed on composite nose cone.

“Visual indications / minor damage observed on LO2 tank and Intertank acreage TPS and components. Majority of TPS impacts < 0.10” deep. Characterized as superficial or witness marks (no discernible depth). Performed sampling of ‘worst-case’ depths using scale (defects >0.10” deep). Performed loads evaluation of 78.7 kt peak wind. Peak wind condition exceeds design certification environment (74.5 kt).”

Although the flight rationale was always expected – given the lack of any noticeable damage – the depth of the evaluation is a testament to the amount of data and flight history the Shuttle Program utilizes to ensure they are confident the flight hardware is in an acceptable condition.

“Rationale for Acceptance Summary: Composite hardware is damage tolerant. No visual indications. Testing at 20 ft-lbs impact energy result barely visible damage. Max impact energy for ET-122 hail event is 0.62 ft-lbs (0.47” hail at 107 mph winds),” the presentation added.

“Bounded by ET-124 Max impact energy of 5.92 ft-lbs. Residual hail defect locations do not provide a leak path across the GO2 Vent Seal Land surface. Similar to condition accepted after launch scrub (after vent hood retraction). No continuous leak path over face of dock seal land. Aero recession performance assessed to be nominal.

“ET-122 damage is bounded by ET-124 hail damage testing. Surrounding TPS analyzed at higher recession rates around the cavity. Residual crushed foam ablates at nominal rates as demonstrated by test (crush damage 5, 10, 15 and 20 percent for 1” thick TPS). Crushed foam liberates as normal ablation products. Thermal assessment. No impact to ascent or entry requirements.”

ET-124′s data is highlighted by the evaluations, due to the damage it suffered from a hail storm ahead of the STS-117 launch in 2007, resulting in the rollback of the stack for repairs in the Vehicle Assembly Building (VAB). However, the presentation also used data from ET-129 as part of the rationale. Even post-Return To Flight data was used to back up the readiness of the tank to fly.

“Condition enveloped by similar condition analyzed for STS-126 / ET-129. No impact to icing and launch probability requirements. Configuration of ET-122 hail damage sites would be encompassed by the icing tests done for ET-124 hail damage to meet an 85 percent Launch Probability requirement. No impact to propellant quality requirements. Insignificant quantity of impact sites to affect propellant quality.

“TPS Debris Assessment: Undetected crushed foam due to collateral damage was a major emphasis during RTF II. Large amount of mechanical property and performance testing previously performed to understand performance of both detected and undetected crushed foam. Results of tests showed no impact to TPS performance for crush levels (up to) 20 percent (visually detectable).”

With the ERB debating the status of the vehicle ahead of the PRCB, along with the PRCB then providing the documentation to clear the tank to fly, the Agency FRR did not have to spend much time in concurring with the evaluations, and passing ET-122 to fly as-is.

Another article will follow on the specifics of ET-122′s FRR documentation, including the previous tank (ET-137) performance during STS-133′s launch - and the history of the 10 year old tank which is set to fly with Endeavour.

(Numerous articles will follow. L2 members refer to STS-134 coverage sections for internal coverage, presentations, images and and updates from engineers and managers. Images used: All via L2 content and L2 presentations).

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STS-134 Latest:

Endeavour is snugly protected inside the Rotating Service Structure (RSS) at Pad 39A, although the top of her tank is exposed to the elements. While it is not confirmed hail actually hit the tank – for the second time in around a week – inspections have shown no additional areas of interest, following what was only minor damage from the previous storm.

“OV-105/SRB BI-145/RSRM 113/ET-122 (Pad-A): Tuesday’s bad weather generated reports of possible hail observed on OTV (TV Cameras) at the pad. Another iteration of S0018.100, Op 90 has been generated. (However,) Instrumentation did not have any corroborating evidence of hail at Pad-A,” noted the NASA Test Director (NTD) report (L2).

“ET Mechanical, Launch Site Support, NASA Safety, and MAF (Michoud Assembly Facility) representatives completed a walk-down with no new observations of damage on the ET found.”

Interestingly, work is still being completed on clearing the vehicle and pad from the initial storm last week, although the Engineering Review Board (ERB) are officially satisfied that ET-122 is safe to fly as-is – with the very minor damage not requiring any repair work.

“The ERB also concluded that the ET foam hail indentations will be ok to fly as-is, and dynamic loading on the SRB (Solid Rocket Booster) hold down posts should not be a concern,” the NTD report noted. “Ground Support Equipment (GSE) evaluations still remain to be completed, as well as the GUCP (Ground Umbilical Carrier Plate) alignment guide pin fit check.”

Processing has continued in a nominal fashion since the four additional – and since closed – Interim Problem Reports (IPRs) were generated during the Terminal Countdown Demonstration Test (TCDT).

S0024 HPU hydrazine loading operations have been completed, while the APU/HPU (Auxiliary and Hydraulic Power Unit) cart lowering and transport to the fuel farm is in work this week. S5009 Ordnance Installation has been rescheduled to April 18 following the change to the launch date to April 29, caused by an International Space Station (ISS) schedule and Dual Docked Operations (DDO) conflict with a Russian Progress resupply ship.

Several tankers of LH2 are expected at the pad complex on Friday, while preparations are continuing to push towards offline testing of STS-134′s primary payload, the Alpha Magnetic Spectrometer-2 (AMS-02), this weekend – providing work after Friday isn’t impacted by a potential government shutdown.

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

“S07134 AMS End-to-End Test was completed,” added the NTD report. “The AMS payload will be powered up to support off-line testing through the weekend.”

STS-134 SSME FRR:

Endeavour’s ride into orbit at the end of this month will be aided by her three Space Shuttle Main Engines (SSMEs). The noisy trio are no stranger to the aft of the youngest orbiter in the fleet, after pushing her uphill during STS-130. The engines were installed in the following positions on the orbiter: 2059 is ME-1, 2061 is ME-2, while 2057 is ME-3.

With the Space Shuttle Program (SSP) Flight Readiness Review (FRR) completed (15 presentations available on L2), documentation shows managers first overviewed the performance of Discovery’s SSMEs during STS-133 via the In Flight Anomaly (IFA) review at the Program Requirements Control Board (PRCB) meeting (14 presentations available on L2).

“Engine operation was nominal. ME-1 2044, ME-2 2048, ME-3 2058 – No SSME IFA Identified,” noted the STS-133 SSME IFA presentation, outlining the superb performance from the reliable workhorses which have ably supported the Space Shuttle Program since the 1980s. “All SSME observations are encompassed by previous flight and/or test experience and identified as no impact.

“One (minor) observation (believed to be related to the Oxidizer Preburner Oxidizer Valve (OPOV) – though full information is restricted) – was presented to the MMT (Mission Management Team) – no IFA recommended.”

Only one item of interest made it into the FRR documentation for the SSMEs, 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 SSME SSP FRR 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.

“Path limited to E2061 in vicinity of LPO Duct and Controller. No visible evidence of engine contact. Normal electrical pad checkouts conducted. Tactile test of controller harness verified connector integrity.

“Harness “wiggle checks” confirmed internal wire integrity. Potential controller housing impact analyzed. Calculated shock loads within typical vibration levels.”

The presentation continued by overviewing the flight rationale which was presented to managers at the SSP FRR.

“Flight Rationale: Engine hardware inspected and no external or internal damage evident. Electrical Harness Backshells visual and tactile manipulation. Protect sensitive internal wire crimps. Harness “wiggle checks” completed with no anomalies. Effective in finding/confirming electrical intermittents. Controller receptacle integrity confirmed by controller internal pressure check.

“Integrity of ducts, lines, etc. confirmed by visual inspections. Pad verified electrical functions and controller pressure. Harness installation precludes adverse loading or pinching of wiring. Conductors protected by at least three layers of insulation. Potential shock loads to controller housing within vibration experience. Critical functions are redundant.”

Once Endeavour returns home from her STS-134 mission, her engines will be removed and stored, potentially for use with the Space Launch System (SLS), should the ongoing RAC teams at the Marshall Space Flight Center (MSFC) continue to baseline a Shuttle Derived (SD) Heavy Lift Launch Vehicle (HLV) as the Design Reference Vehicle (DRV).

It was back in October of last year when a Program Requirements Control Board (PRCB) meeting recommended the orbiters should gain Replica Shuttle Main Engines (RSMEs) – previously scrapped nozzles installed via an adaptor – for when all three of the vehicles retire to exhibitions, thus protecting the flown SSMEs for potential reuse with the opening SLS flights.

NASA’s scheduled to announce the location of all three orbiter’s retirement homes next week.

The FRR presentation also referenced the readiness of six other SSMEs, three of which are installed on Atlantis for her STS-135 mission – a reference which relates to Atlantis also holding the role of the STS-335 Launch On Need (LON) vehicle, in the event of a highly unlikely need of a rescue scenario for Endeavour’s crew.

The other three engines are allocated to the spare set, in the event any or all of Endeavour’s SSMEs require changeout prior to launch.

“STS-135 Engines: ME-1 2047 ME-2 2060 ME-3 2045. Engines installed on Atlantis 7-9 December 2010. Engines reviewed and ready to support contingency if required,” the SSP FRR SSME presentation added. “Spare Engine set: ME-1 2052 ME-2 2051 ME-3 2054. Post-flight processing and checkouts complete. All current flight and ground test anomalies have been evaluated with respect to impact on Flight Engines.”

(Numerous articles will follow. L2 members refer to STS-134 coverage sections for internal coverage, presentations, images and and updates from engineers and managers. Images used: Larry Sullivan MaxQ Entertainment/NASASpaceflight.com and via L2 Presentations).

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STS-133 Delta SSP FRR:

The Delta SSP FRR was mainly an update of the baseline SSP FRR – which was conducted on October 6 – whilst focusing on the work carried out on ET-137 via modifications to the stringers, an impressive effort to mitigate the potential of cracks forming on the intertank support beams.

The problems with the stringers were first noticed via a large U-shaped crack on the LO2/Intertank flange foam via Infra-red cameras at the pad during the draining of ET-137 – after STS-133′s launch countdown was scrubbed due to a leak from the tank’s Ground Umbilical Carrier Plate (GUCP).

Departmental reviews mainly noted “no constraints pending the closure of open work,” as is usual for this stage of the preparations for flight, added to other notes from SSP management which conveyed “there is some good agreement.. should be able to clear it out and get February 24 as the STS-133 launch date.”

That launch date won’t be officially set until the Agency Delta FRR next week, pending the successful launch of the Ariane 5 ECA carrying ATV-2 on the opening launch attempt.

From a flight rationale standpoint, the superb multi-center effort into the root cause evaluations – and resulting modification involving radius block installation on the tank’s stringers – has resulted in a large amount of confidence the tank won’t suffer from additional cracks, either during the tanking or – more importantly – the ascent uphill, avoiding the main concern of foam liberations and the overall integrity of the tank during flight.

“The modifications to ET-137′s LO2 stringer ends and the associated TPS (Thermal Protection System) work is complete. The test matrix to support flight rationale for the ET stringer modifications continues to be executed, with a scheduled completion date of February 11th,” noted pre-FRR notes (L2).

Only one area of flight rationale remained in work heading into the review, relating to test matrix work on stresses on one area of the stringers – work which was expected to be completed on Friday.

It is not clear if the test matrix was available in time for the Delta SSP FRR review, or if it will be signed off at the Agency FRR – given the SSP review was due to take place on Thursday, prior to a one day delay, with review documentation already created earlier this week.

“A brief status of the work being performed in support of flight rationale was provided. One of the key elements of this flight rationale is ensuring the modification does no harm,” added the notes.

“Since the radius block mod stops short of fastener 8, where the stresses are the highest, there is concern that the modification could increase the stress concentration at fastener 8 and result in a more undesirable failure mode. The test matrix includes tests to address this concern and is scheduled to be complete by Friday.”

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

Other updates, which will play a role in the considerations of managers at the Agency Delta FRR, includes the status of the International Space Station (ISS), ranging from the failure of the Water Processing Assembly (WPA) on Station – which would have led to debate over water supplies during STS-133 – prior to its speedy recovery the next day.

STS-133 Pad Flow Latest:

Despite the return of new Interim Problem Reports (IPRs) into Discovery’s pad flow since her return to Pad 39A, processing remains on track for the February 24 launch date, with several days of contingency remaining in the schedule.

Discovery has been put through S5009 Ordnance Installation tasks, alongside orbiter closeouts on her aft section and the scheduled move towards preparations for S0007 Launch Countdown operations.

“S5009 Ordnance Installation/Connection: Call to stations was completed Thursday afternoon at 1400 EST. SRSS open loop test, flight code load, and interface test are complete. Ordnance installation and connections are complete,” noted the latest NASA Test Director (NTD) report (L2).

“In work dropping the BDA (Blast Danger Area) clear and opening the pad for controlled work. S1287 Orbiter aft closeouts continue. S0007 Launch Countdown preps began Friday and continue next week. Weekend work: No weekend work per current schedule.”

Numerous new IPRs have been charged to Discovery’s pad flow over the past two days, most of which have either been cleared as a constraint to the flow or are in the process of being cleared.

The IPRs range from an Inadvertent Switch Throw on a circuit breaker, to a LO2 temperature transducer showing off-scale low, when should be off-scale high, on the orbiter’s Main Propulsion System (MPS).

On the latter issue with the Engine 3 LO2 temperature transducer, troubleshooting revealed that “dropouts occurred when a wire at the backshell was wiggled. Dropouts also occurred when spot ties and tape was removed,” according to the NTD report, which confirmed the harness segment will be removed and replaced when time in the flow allows.

“Every effort was made to address the suspect 2-foot section of the wiring harness, however, the time necessary to complete work in the aft was too long to support ordnance operations. Additional time will be scheduled to complete the harness segment R&R.”

On the latest issues reported on Friday, IPR-89 and 90 – the latter of which was related to a problem during the SRB (Solid Rocket Booster) recovery system test, not unlike the issue during STS-129′s pad flow, will both be closed.

“IPR-0089: During flight code installation, Automatic Gain Control (AGC) levels of the left SRB, right SRB and GSE (Ground Support Equipment) were 7 dB low,” the NTD continued. “The Signal Generator was suspect and swapped out, resolving the problem and allowed testing to continue. This IPR will be upgraded to a GSE PR (Problem Report) and closed.”

The main item of interest continues to be with the GUCP, which produced at least one small leak during testing once it was connected to the tank. This resulted in managers calling for the system to be disassembled to allow for the changeout of its two part flight seal on the Quick Disconnect (QD).

However, once the GUCP was reinstalled to the tank, another problem was noted when the right hand pivot assembly – a key part of the system, given its relation to the GUCP’s alignment – showed a small amount of movement.

Because any threat of misalignments in the GUCP system can lead to leaks during tanking, managers are discussing if any further work that may be required to aid confidence in the system.

“The flight seal was removed and replaced and flight seal torques are complete. 7” QD installation is complete. Ventline raising/mate, GUCP alignment measurements, draw weight lowering, and GUCP electrical connects were completed,” noted the NTD report.

“However, a small movement in the right hand pivot assembly was measured after vent line connect and prior to withdrawal weight and the pivot pin became loose. After some discussion it was decided to proceed with withdrawal weight operations.

“Engineering wants to convene the GUCP leak investigation team to discuss the movement and the next possible course of action.”

Good news has been reported since the re-installation, with leak checks on the system passing without issue. This should lead to a nominal tanking later this month, especially after the mitigation approach of “clocking” the carrier plate after the GUCP leaked during the November launch countdown. An update will be published, should the investigation team decide to take action on the pivot assembly.

Another new item of interest was also noted on Friday, relating to loose fasteners being observed on Atlantis’ Space Shuttle Main Engine (SSME) dome heat shields, leading to borescope inspections being carried out on sister Discovery out at the pad. Engineers did find some minor discrepancies with Discovery’s hardware during the inspection, which is currently under review.

“An anomaly (loose fasteners) discovered on OV-104′s (Atlantis) SSME dome heat shield (DHS) splice lines generated the need to inspect OV-103′s (Discovery) splice lines via borescope,” the NTD noted. “Discrepancies were discovered on flap seal installation for engines 2 and 3 and an unexpected gap on the engine 2, lower splice. Engineering is reviewing the data and borescope images, and developing rationale.”

Other issues in Discovery’s eventful pad flow of late are being closed, as the NTD updated the status of several items of interest, ranging from the Feeler Gauge – which fell apart as an engineer was working on the GUCP work, sending numerous blades down the stack, one of which caught the External Tank – to the loud noise heard by engineers during the hyperloading tasks on Discovery’s SRBs.

“Feeler Gauge Fall Update: All 13 of the gauge blades have been recovered. Corrective Action Engineering (CAE) has impounded all the pieces/parts for final resolution and accountability. Minor damage in an unaccessible area of the hydrogen acreage foam of the ET was discovered and has been evaluated with high magnification photos. ET Project has deemed the missing foam nodules to be acceptable as is.”

“Pad A loud noise: Thursday’s ERB (Engineering Review Board) concluded that the noise was a ‘transient event’ with no detrimental effects. Data suggests no load was transferred to the vehicle. Walk-downs and data review indicate no discrepancies with hardware or facilities.”

IPRs and items of interest during this stage of the pad flow are common and are usually cleared without any impact to the schedule, thanks to the highly experienced engineers who care for the shuttles. None of the issues reported above have even impacted the contingency days in the STS-133 schedule towards launch.

(Further updates and articles will follow. Refer to live coverage threads linked above. L2 members refer to STS-133 live coverage sections for internal coverage, presentations, images and and updates from engineers and managers. Images used, Larry Sullivan MaxQ Entertainment/NASASpaceflight.com and via L2 acquired PRCB presentations).

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STS-133 Pad Flow Latest:

The loading of Discovery’s PRSD systems allows the orbiter to store the reactants (cryogenic hydrogen and oxygen) which will be used to supply the three Fuel Cells (FCs) – which in turn provide all the electrical power for the vehicle on orbit.

Loading of the reactants is always scheduled early into S0007 operations, along with any required offload, which in turn holds relation to the fine-tuning of the Ascent Performance Margin (APM).

“OV-103 / SRB BI-144 / RSRM 112 / ET-137 (Pad-A): The STS-133 S0007 Launch Countdown is underway and proceeding nominally along the timeline. Call to stations was completed on Sunday at 1330 hrs and the countdown clock picked up and began counting at 1400 hrs,” noted the latest NASA Test Director (NTD) processing report (L2).

“Avionics configuration and checkout completed on Sunday. Preparations for PRSD load completed this morning (Monday) at 0500L. The vehicle and pad were configured for remote operations in preparation for orbiter, SRB (Solid Rocket Booster) PIC tests and PRSD load which is scheduled to begin shortly.”

PRSD loading began at 11:30 local on Monday, continuing through the first shift with the pad re-opening at approximately 17:30 -  followed by the planned PRSD LH2 offload. Preparations were also carried out on the External Tank, ahead of Wednesday morning’s tanking operations.

The NTD also officially cleared two of the recent Interim Problem Reports (IPRs) from Discovery’s list of issues, following the successful resolution of troublesome Quick Disconnects (QDs), in order to allow the completion of the pressurization tasks on Discovery’s Right OMS (Orbital Maneuvering System).

“IPR-52 RH OMS GN2 QD 525 update: All work is complete and the problem was resolved over the weekend. Flight cap installation and door closeouts were worked on Sunday. Troubleshooting over the weekend removed and replaced the QD on Saturday with additional troubleshooting performed when the GN2 tank continued to vent. This issue was isolated to a GSE valve. The tank is now pressurized for flight,” added the NTD.

“IPR-53 RH OMS GHe QD 515 update: This issue was also resolved with all troubleshooting and corrective measures completing prior to S0007 CTS (Call To Stations). The QD was successfully removed and replaced on Saturday with flight pressurization finishing early on Sunday morning. Mass specs were also worked on Sunday morning with no discrepancies.”

Two additional IPRs have been listed by the NTD – both minor and hold no impact to the flow – the latter of which was noted later on Monday, relating to a “primary panel dome and handrail” which will require changing out late on Monday. IPR-54, meanwhile, related to a display issue on an event timer, which was in the process of being cleared at the time of Monday’s NTD report. 

STS-133 Specific Articles: http://www.nasaspaceflight.com/tag/sts-133/

“IPR-54: Picked up IPR against Forward Event Timer, 10th digit top left is out. T/S (Troubleshooting) plan is to look at Fault Light documentation. Constraint is S0007.200 15-507. T/S reveals Event Timer operating nominally with one segment out. (Engineering) recommends going MR (Material Review) to fly as-is and the test team is in concurrence. Will verify the Commander has no issues with flying as-is when the crew wakes up.”

SSMEs Ready To Fly:

On Tuesday, the Space Shuttle Main Engines (SSMEs) will undergo their final preparations for launch – a processing task set to begin once the count is released from the 8 hour Built In Hold (BIH) at T-19 hours.

UPDATE: (Task was on hold due to IPR-58 relating to Main Engine Controller (MEC) issue. Engineering Review Board (ERB) discussing – and cleared after recycling – before once again showing problems. New article pending.)

As per usual, the three workhorses on Discovery’s aft are expected to perform as advertised during ascent, with Flight Readiness Review documentation (over 50 presentations, available on L2) overviewing their status.

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.

For STS-133, Main Engine 1 (ME-1) is serial number 2044, ME-2 is 2048 and ME-3 is 2058. All their related hardware is the same as that which flew with Atlantis, bar a couple of elements, such as a new nozzle for ME-1.

As is usual for the FRR process, previous flight experience and previous In Flight Anomalies (IFAs) are brought to the table for discussion.

These included a one page review regarding IFAs as far back as STS-130, such as “Nozzle 5014 Thermal Discoloration & Damage,” and an “Accelerometer Disqualification” issue on STS-131, all of which were minor and classed as “closed”.

The last flight – STS-132 – was the main subject of the FRR’s deliberations, which concentrated on one of Atlantis’ IFAs, relating to Nozzle 5007′s Flow Recirculation Inhibitor (FRI), which was seen to be frayed in an “area of higher gap and negative protrusion” at the top of the nozzle.

“Background: FRI is used to reduce hot-gas flow and seal bluing in area of MCC/nozzle G15 joint. Bellows seal prevents leakage to aft compartment. Fraying identified during standard post flight inspections,” noted the Agency FRR presentation for the SSMEs.

“Nozzle demated from MCC (Main Combustion Chamber). No bellows seal discoloration. Materials evaluation of FRI showed broken fibers, no indication of overheating or melting.”

The documentation continued by noting the history of this specific area of the engine, along with how improvements have continually been made over the near-30 years they have flown with the Space Shuttle.

“Original joint configuration had very small gap between MCC aft tip and nozzle tubes. No seal discoloration in the first 25 flights (no FRI used),” added the presentation. “Re-occurring issues with MCC and nozzle tube contact/damage (led to) gap between MCC and nozzle increased to mitigate MCC damage.

“After STS-26R, an overheated and cracked bellows seal was found (no FRI used). Analysis and testing defined influence of cavity entrance geometry on hot-gas recirculation into bellows seal cavity. Crown leakage also identified as a contributor to recirculation. FRI introduced to inhibit recirculation flow.

“First flight of FRI was STS-33R. FRI appeared to reduce, but not eliminate recirculation. Thickness of FRI later increased to improve effectiveness.”

Also referenced was the complex testing and analysis via Computational Fluid Dynamics (CFD) models, in order to simulate circumferential recirculation in bellows seal cavity, with the results noting the Nozzle/MCC gap and nozzle tube protrusion cause hot gas recirculation, leading to the introduction of the FRI material.

“FRI developed to reduce hot gas flow to the G15 seal. (Made from) Ceramic fiber rope (which) withstands high temperatures.

“(It is) pliable (and) provides a flow resistance to reduce circumferential circulation in the G15 cavity. Installed in 4 sections (2 long and 2 short). Long sections clocked in high protrusion areas,” the presentation continued.

“Standard FRI (was used between) 1988 to 1995. Seal bluing on units with large gaps (was noticed, leading to) enhanced FRI (being) developed. Contains approximately 5 times more batting than standard FRI. Blued seals occurred less frequently. Always associated with high gap and protrusion and/or leakage.”

The FRR also looked at recent flight history, such as the numerous – yet tiny – nozzle leaks suffered on STS-128′s launch (originally seen during STS-127), cited as a contributor to a weakened/shifted FRI, although this caused “no damage/effect on (the G15) seal,” thus aiding the subsequent flight rationale for both STS-133 and STS-134.

“Rationale for flight: Frayed FRI did not affect G15 seal during STS-132. Significant hot fire experience without FRI. Dominant influences in seal bluing are gap/protrusion/leakage. STS-133 and STS-134 units have gap and protrusion within acceptable limits per hot-fire experience.

“STS-133 and STS-134 have no significant leakage near G15 (seal). STS-133 and STS-134 nozzles have no history of seal bluing.”

The relevance to STS-134 is noted due to Endeavour holding the role of Discovery’s LON (Launch On Need) vehicle. Managers always aim to be confident of clearing any potential issues on all future flights, in order to avoid the potential nightmare scenario of a problematic launch during a rescue mission – as much as requiring a LON mission is highly unlikely.

“Launch on Need Assessment: STS-134 Engines: ME-1 2059 ME-2 2061 ME-3 2057. Engines installed on Endeavour 27 – 29 July 2010,” added the presentation. “Engines reviewed and ready to support contingency if required. Spare Engine set: ME-1 2045 ME-2 2060 ME-3 2047. Post-flight processing complete.

“All current flight and ground test anomalies have been evaluated with respect to impact on Flight Engines.”

Thanks to the historical and current confidence gained via the SSME FRR evaluations – which will prove to be priceless if, as currently expected, the SSMEs live on via the Heavy Lift Launch Vehicle (HLV) or Space Launch System (SLS) – managers polled to give their approval for the SSMEs to help Discovery make her final ascent into space.

“SSME Mission Readiness Assessment: The Discovery Main Engines are in a ready condition for STS-133.”

(Lead Image via HD QuVIS Video of SSME Start (L2). Graphics via L2. SSME installation image via NASA.gov)

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Nominal Mission Timeline Overview:

Following liftoff on FD-1, Discovery’s crew will perform the standard post-insertion activities, NC-1 course correction/phasing burn, SRMS (Shuttle Remote Manipulator System) powerup and checkout, PMM (Permanent Multipurpose Module) environmental checkouts, and FD-1 downlinks/downloads – including ET umbilical well photographs, ET hand-held video and stills, and WLES (Wing Leading Edge Sensor) data.

This will be followed by the standard inspections of Discovery’s RCC (Reinforced Carbon-Carbon) WLE (Wing Leading Edge) and Nose Cap panels and T0 umbilicals by the crew via the OBSS (Orbiter Boom Sensor System), Hi-Res digital imagery of the OMS Pods, and inspection of the Upper Flight Surfaces via the SRMS on FD-2.

This Flight Day will also include the NC2 and NC3 burns, EMU (Extravehicular Mobility Unit) checkout, Centerline camera installation, Docking Ring extension, and Rendezvous Tools checkout.

Then, on FD-3, Discovery will rendezvous with and dock to the International Space Station after performing the customary R-bar Pitch Maneuver (RPM) to allow ISS crewmembers to photograph her underbelly TPS (Thermal Protection System) tiles.

Given a Monday, Nov. 1 launch at 1640 EDT, Discovery will dock to the ISS at ~13:13 EDT on Wednesday, Nov. 3.

Following docking, the ISS crew will downlink all RPM photographs and ELC-4 (EXpress Logistics Carrier 4) will be unberthed from Discovery’s payload bay and installed on the S3 truss’s PAS. This installation will be accomplished by extracting ELC-4 from OV-103′s PLB using the SSMRS (Space Station Remote Manipulator System), handing off ELC-4 to the SRMS, the SSRMS walking-off from Node-3 to the Mobile Base Station (MBS), handing off ELC-4 back to SSRMS, and SSRMS installation of ELC-4 to PAS.

N2 transfer from OV-103 to ISS will also commence on FD-3 and the SSRMS will be walked-off to Node-2 for overnight stowage.

STS-133 Specific Articles: http://www.nasaspaceflight.com/tag/sts-133/

On FD-4, the SSRMS will remove the OBSS from Discovery’s payload bay and hand it off to the SRMS. The SSRMS will then walk-off to the MBS where the MT (Mobile Transporter) will be reconfigured for translation.

Middeck transfers are scheduled to begin on FD-4 and EVA tool configuration will be undertaken in preparation for EVA-1 the following day. The ISS/Discovery crew will then review all EVA procedures for EVA-1 before Tim Kopra and Al Drew perform and O2 pre-breathe and campout in the Quest Airlock of the ISS.

FD-5 will see the first of two planned EVAs for the STS-133 crew. Scheduled to last approximately six hours thirty minutes, Kopra and Drew will work on the J612 cable, stow the failed Pump Model (which failed in late-July), work on equipment on the Z1 truss, relocate material back to the ISS airlock, work on the Starboard CETA Rail stub, and perform the JAXA message in a bottle experiment before re-entering the ISS.

For EVA-1, the SSRMS will support EVA operations from its base on the MBS PDGF (Power Data Grapple Fixture). Following the EVA, the SSRMS will be reconfigured for MT translation.

Middeck transfer will also continue on FD-5 and the CWC-I will be filled.

Finally, the MT will be translated from WS2 to WS3 for the overnight and the SSRMS will be walked-off by ground controllers from the MBS to Node-2.

Then, following the whirlwind of activity on FD-5, a historic milestone will be reached on FD-6 as the final permanent U.S. module is attached to the International Space Station.

Using the SSRMS, PMM Leonardo, the workhorse of the MPLM fleet, will be unberthed from Orbiter Discover and berthed to the Node-1 Nadir port.

One hour thirty minutes of time will also be set aside on FD-6 for a Focused Inspection (FI) of Discovery’s TPS in the unlikely event that serious launch or MMOD (Micro Meteoroid Orbiting Debris) damage is detected via the FD-2 OBSS inspections or the FD-3 RPM photography.

However, should the FI prove unnecessary, the 1.5 hours in the FD-6 timeline would be reassigned to Node 1 1553 jumper installation, Node 1 Nadir vestibule jumper installation, and PMM activation/ingress. Additionally, should more than the allotted time be required to complete the FI, the necessary time would be pulled from other areas of the mission timeline.

Joining the FI activity on FD-6 are the continuation of middeck transfers, EVA tool configuration, EVA procedures review, PMM vestibule pressurization, overnight campout in the Quest Airlock for Drew and Kopra, and the configuration of the SPDM (Special Purpose Dexterous Manipulator, or Dexter) by MCC-H.

FD-7 will then be devoted to the execution of the second and final planned EVA of the STS-133 mission.

Scheduled to last ~6.5 hours, EVA-2 will see the venting of the failed Pump Module, ELC-4 ExPCA MLI (Multi-Layer Insulation) removal, LWAPA retrieval and installation into Discovery’s Payload Bay, TS Stop stow, S3 MT Stop stow, Starboard CETA cart reconfiguration, JSB retrieval, SPDM CLPA1 installation, P3 CETA light installation, SPDM EP1 MLI removal, P1 RBVM MLI repair, P1 grapple beam troubleshooting, SSRMS elbow camera lens cover installation, Node-3 MLI removal, SPDM CLPA lens cover installation, and POA CLA lens cover installation.

Node-1 jumper installation and PMM activation/ingress will also occur on this day if they are not performed on FD-6; middeck transfers will also continue on this day.

Flight Day 8 for the STS-133 crew will see an O2 transfer from OV-103 to ISS (provided pre-launch O2 offloads do not preclude this activity). A GLACIER unit will be swapped between the ISS and Discovery – a task that will involve a MELFI sample transfer.

A “H2 Dome Transfer (foam from PMM) to middeck” task is also on the mission schedule for this day, as is a reboost of the ISS via Discovery’s Reaction Control System.

The crew will also enjoy some well-deserved off duty time on FD-8.

Then, on FD9, the crew will carry out the necessary steps for Discovery’s undocking from the International Space Station.

Following final middeck transfers between OV-103 and the ISS, and the transfer all STS-133 EVA equipment from the Quest Airlock back to Discovery, the crew will enjoy some more off duty time before bidding their ISS colleagues farewell and closing the hatches between Discovery and the ISS for the final time.

After a night’s sleep, Discovery and the STS-133 crew will depart the ISS with an undocking planned for an MET (Mission Elapsed Time) of 8 days 14 hours and 8 minutes. Discovery is scheduled to perform the customary fly around of the ISS as part of her departure before moving out “ahead” of the ISS.

The crew will spend the remainder of FD-10 performing a Late-Inspection of Discovery’s TPS before stowing the OBSS and powering down the SRMS. A potential “orbit adjust burn” is also on the schedule for FD-10.

EOM-1 (End of Mission -1 day) would then follow on FD-11, with cabin stow, Ku-Band antenna stow, and a water dump. However, the biggest activity of the day will be the Flight Control System checkout, RCS hot fire test, L-1 (Landing -1) comm checks, and WLEIDS deactivation.

Moreover, NASA will mark Discovery’s last scheduled full day in space with a special tribute on FD-11.

Then, if all goes to plan, and the weather is acceptable, MCC-H will give the STS-133 Flight Crew the go-ahead to deorbit Discovery during her 169th orbit of Earth on STS-133. 

While the exact times for the Deorbit Burn and Landing will vary based on the actual day and time of Discovery’s launch and actual orbital dynamics, the approximate time of the Deorbit Burn on orbit 169 (based on a Nov. 1 launch at 1640 EDT) would be at MET 10 days 17 hours 57 minutes (or 0937 EST) with a landing on orbit 170 at the Kennedy Space Center at MET 10 days 18 hours 59 minutes – or 1039 EST Friday, November 12, 2010.

If this timeline holds (in terms of calendar dates), STS-133 will mark the completion of the five Space Shuttle mission dedicated to assembly of the International Space Station in a one-year time span (STS-129 in November 2009 – STS-133 in November 2010).

The mission will also mark the completion of Shuttle flight operations for calendar year 2010 and the second flight of Discovery and the PMM Leonardo this year.

Minimum Duration Flight and Mission +1 Day:

While Discovery’s mission is planned as an 11+1+2 day flight (11 flight days + 1 mission extension day + 2 landing contingency days), the possibility always exists that a systems failure or crew illness could force a Minimum Duration Flight (MDF) scenario.

For STS-133, this would mean the elimination of both EVAs and five Flight Days from the mission timeline.

Under the agreed upon MDF timeline for STS-133/ULF-5, the first two FDs would carry out in an identical fashion to those under the nominal mission timeline. Then, from FD-3 on, the flight would support the completion of all CAT I mission objectives as referenced in the Reference Flight Rule ULF5_C2-15.

Under this rule, FD-3 would consists of rendezvous, RPM, docking, and ELC-4 unberth and installation to S3 nadir inboard PAS.

FD-4 would then require the unberthing and handoff of the OBSS by the SSRMS to the SRMS. The SSRMS’s cameras would then perform an inspection of the PMM’s PCBM (Passive Common Berthing Mechanism) before unberthing the PMM from Discovery and installing it to Node-1 Nadir.

The transfer of all mandatory and critical items per the ULF-5 Transfer List would also take place on FD-4.

FD-5 would then be used to perform a FI of Discovery’s TPS (if required) and minimal PMM activation. The crew would also receive some off duty time on this day before returning to Discovery and closing the hatches between Discovery and the Space Station.

Discovery would then undock on FD-6 with her Flight Crew stowing the OBSS for reentry and performing the customary EOM-1 activities as referenced in the nominal mission timeline overview.

The STS-133 crew would then deorbit Discovery and return to Earth on FD-7.

However, there is also the possibility that Mission Managers could decide to make use of the +1 day that the ULF-5 flight carries.

According the MOD FRR, “The +1 mission extension day may be used to accommodate docked contingencies.”

These docked contingencies include additional time necessary to complete all possible FI ops over the already baselined 1.5 hours, additional time needed to complete all CAT I IVA (Intra Vehicular Activities) objectives, and additional time needed to complete EVA ops.

(Lead Photograph: Larry Sullivan, NASASpaceflight.com and MaxQ Entertainment. Graphics: L2 STS-133 FRR presentations)

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STS-133 Pad Flow Latest:

Discovery herself is suffering from no issues during her pad flow, and continues to hold several days of contingency time based on a November 1 launch date.

The week’s milestones have been centered around numerous system checks, along with the arrival of Discovery’s STS-133 payload to the pad. Although the arrival was delayed by a day, due to a problem loading the Permanent Multi-purpose Module (PMM) into the payload cannister for the ride out to 39A, movie crews still managed to film scenes for the 2011 blockbuster Transformers 3.

Kennedy Space Center (KSC) workers note that a large amount of filming took place with Discovery in full view, given the Rotating Service Structure (RSS) had been opened for the arrival of the payload – a milestone which had been delayed 24 hours due to the loading cell problem.

“OV-103 / SRB BI-144 / RSRM 112 / ET-137 (Pad-A): The vehicle was powered up to support OMS/RCS (Orbital Maneuvering System/Reaction Control System) cross-feed checks, APU (Auxiliary Power Unit) decay checks, and MSBLS (Microwave Scan Beam Landing System) time/cycle test,” noted the NASA Test Director (NTD) processing update (L2).

“All were successfully completed, less APU decay checks, which are complete to date.”

“S0600 Vertical Payload Operations: The RSS was rotated to the park position to support payload arrival and installation operations. During system walkdown it was noticed that the MLP (Mobile Launch Platform) side 2 vacuum pump coupler was broken; the coupler has been R&R’d and the system is operational.”

With a quick resolution for the vacuum pump issue, the payload arrived at the pad in the early hours of Thursday and was transferred to the Payload Ground Handling Mechanism (PGHM) in the Payload Checkout Room (PCR).

“CTS (Call To Stations) for S0600 occurred at 0001 EDT. The payload arrived at 0201 EDT and lift to the PCR. Lift first motion occurred at 0546 EDT. The payload was transferred to the Payload Ground Handling Mechanism in the PCR. Canister lowering and RSS rotation (on the upcoming schedule).”

However, the operation to transfer the payload from the cannister to Discovery’s Payload Bay suffered a problem, relating to a failed hard drive on the control console that is responsible for the critical operation of handing over the payload to the orbiter.

“NEW PR (Problem Report): The transfer of the payload to the Payload Ground Handling Mechanism (PGHM) was delayed 24 hours because of a PGHM control console error. The issue has been isolated to a failed hard drive which was replaced,” the NTD noted.

“Canister lowering and transport back will be completed tonight (Friday). RSS rotation to mate will occur Saturday morning. Payload Bay door opening is now scheduled for Saturday morning. Payload installation into the Orbiter is scheduled for Monday morning.”

Engineers will continue to work through the weekend on payload operations. With around six days worth of contingency in the flow, no impact on the launch date is expected from this week’s delays.

STS-133 SSP FRR:

Over at the Johnson Space Center (JSC), the second most important Flight Readiness Review (FRR) for the mission was conducted by the Space Shuttle Program (SSP) on Wednesday. A second day’s worth of meetings wasn’t required, a sign of how smoothly the review proceeded.

The SSP FRR is the result of numerous departmental meetings, with all major hardware and mission reviews presenting to the SSP management. In total 27 presentations (Main and Backup) were produced for review by the managers (available on L2, with numerous articles to follow).

“All Orgs polled go to proceed to STS-133/ULF5 Agency FRR on 10/25,” flashed a memo (L2) on Wednesday evening, marking a successful review, as the mission presses forward to the final FRR later this month.

Normally the Agency FRR follows one week after the SSP FRR. However, scheduling conflicts with key managers who are involved with International Space Station meetings, resulted in the delay to just prior to the start of the launch countdown.

This is not expected to be a problem, due to the very “clean” nature of the SSP FRR, which raised only the one “action item” – relating to the frangible nut on the Solid Rocket Boosters (SRBs).

Although such a failure during a launch would result in a LOV/C (Loss Of Vehicle/Crew) scenario, the action item will gain the expected Flight Rationale in time for the Agency FRR at the Kennedy Space Center.

“The SSP FRR has concluded. All orgs polled Go to proceed to the Agency FRR on 10/25 in support of launch on November 1st,” noted the prefacing memo noting the green light gained at the SSP FRR.

“The review was very clean with no exceptions and only one action item issued related to an open SRB item for a frangible nut that failed Destructive Lot Acceptance Testing.

“Flight rationale is in work and is expected to be based on STS-133 and STS-134 boosters flying frangible nuts from a different lot that has passed testing and has flown since STS-125. An FRR action was issued to bring this item to a PRCB (Program Requirements Control Board) or noon board prior to the Agency FRR.”

STS-133 Specific Articles: http://www.nasaspaceflight.com/tag/sts-133/

Also gaining a mention was the failed Pump Module on the External Thermal Control System (ETCS) Loop A, which was recently replaced via several Stage EVAs. The failed unit is scheduled to be returned on Atlantis, via what remains a notional STS-135 mission, due to concerns relating to the appropriation of funding via the approved Senate Bill (article next week).

Pre-empting its return, managers have decided to add a task to EVA-2 on STS-133, requesting the space walkers to vent any remaining ammonia from the unit, in order to mitigate a potential flammability issue once the hardware is installed inside Atlantis’ Payload Bay for the return to Earth.

“STS-133/ULF5 is an 11+1+2 day mission with two scheduled EVAs, scheduled to launch on November 1st at an inplane time of 1540 central. The cargo complement includes the Permanent MPLM (PMM) and External Logistics Carrier 4 with a spare radiator and five open FRAMs,” continued the SSP FRR approval memo.

“The only significant open item is the analysis related to the pump module ammonia vent. The pump module is expected to have a small amount of ammonia (less than ~10 lbs). Analysis showed that if this ammonia was released in the payload bay, it exceeds flammability limits. Therefore, a task to vent the ammonia was added to EVA-2 in prep for return on STS-135 if that mission is flown.”

While the task to vent the ammonia is not deemed to be a problem for the EVA tasks, engineers need to check any venting does not find its way on to Discovery’s aft hardware or one of the ISS’ solar arrays. That analysis is currently being conducted, with a backup plan to add the task to a Stage EVA, when an orbiter is not docked to the orbital outpost.

“A potential concern with the vent is impingement on the Orbiter tail and OMS pods. The vent nozzle can be adjusted 30 degrees but then impingement is on a solar array. Analysis for both of these scenarios is underway,” added the notes.

“SSP suggested that a stage EVA be considered if there are concerns. The expectation is that this issue will be resolved prior to the Agency FRR.”

(Photos by Larry Sullivan, NASASpaceflight.com and MaxQ Entertainment. Payload Photo via L2. Graphics, STS-133FRR Presentations via L2).

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Leonardo: Workhorse of the MPLM Fleet:

Named after the famed Italian renaissance inventor Leonardo da Vinci, construction on Multi-Purpose Logistics Module 1 (MPLM 1) – or Flight Module 1 – commenced in April 1996.

Contracted as part of the original ISS agreement between the international partners, Leonardo, like the two other MPLMs, was constructed by the Italian Space Agency. After the completion of primary construction in August 1998, Leonardo was loaded onto a Beluga aircraft and delivered to the Kennedy Space Center, FL.

From there, final construction was completed and various tests performed to formalize Leonardo’s certification for flight ahead of its inaugural mission on Space Shuttle Discovery as part of the STS-102 flight in March 2001.

Liftoff of Leonardo in Discovery on STS-102 marked the first of 10 MPLM flights to date – seven of which have been conducted with Leonardo; MPLM Raffaello (MPLM 2) picked up the other three MPLM flights, with Donatello unfortunately receiving no flight assignments following the restructuring of the Shuttle manifest in the wake of the 2003 Columbia accident.

Upon return of STS-102, Leonardo was quickly reconfigured for flight five months later on STS-105 – also on Space Shuttle orbiter Discovery.

During STS-105, Leonardo was used to deliver six Resupply Stowage Racks, four Resupply Stowage Platforms, and two new scientific experiment racks for the Destiny lab. Two new science racks and EXPRESS (Expedite the Processing of Experiments to the Space Station) Racks 4 and 5 were also delivered by STS-105 via Leonardo and greatly increased the science capability of the ISS.

Leonardo was then returned to Earth with Discovery where it was deserviced and prepared for its next mission, the STS-111 flight on orbiter Endeavour in June 2002. During this flight, Leonardo was used to transport new experiment racks and three stowage and resupply racks to the ISS.

STS-111 would also mark the final time Leonardo would fly due to the suspension of Space Shuttle flight operations following the loss of Shuttle orbiter Columbia and the STS-107 crew on February 1, 2003. In fact, it would not be until July 2006 that Leonardo would once again be called upon to ferry supplies, experiments, and equipment to the International Space Station.

Returning to active service on July 4, 2006 with the launch of Space Shuttle Discovery and the STS-121 mission, Leonardo carried numerous supplies meant to restart the process of stockpiling the ISS with needed supplies that, while present on ISS, had not been as prevalent during the Space Shuttle Program stand down after Columbia and the year-long stretch between STS-114 and STS-121.

But perhaps Leonardo’s biggest role to date came during her next flight on the STS-126 mission in November 2008 aboard orbiter Endeavour. The near 16-day mission (Leonardo’s longest single-flight duration mission) saw Leonardo carry the final equipment needed for expanding the International Space Station’s crew from three people to six people.

To accomplish this task, Leonardo was launched with a gross weight of 28,100 lbs – 14,000 lbs of which were accounted for by supplies and equipment for the ISS. With no other MPLM flight currently scheduled to exceed this launch weight, Leonardo holds the record for heaviest MPLM flight.

Among the items Leonardo carried to the Station on STS-126 were two new crew quarters racks, a second galley, a second Waste and Hygiene Compartment, the advanced Resistive Exercise Device, two water reclamation racks, new experiments, and a GLACIER (General Laboratory Active Cryogenic ISS Experiment Refrigerator) unit.

After a California landing, Leonardo was returned to the Kennedy Space Center in December 2008 with Endeavour and prepared for its role in the August 2009 flight of Discovery and mission STS-128.

Launching seconds before the stroke of midnight on August 28, 2009, Discovery and Leonardo carried the final pieces of equipment to ease the living conditions of the Station’s six-member crew. Included in Leonardo’s launch manifest were three life support racks, one Crew Quarters for Kibo, a new treadmill named after comedian Steven Colbert, and an Air Revitalization System ultimately destined for Node-3.

Finally, Leonardo was returned to the Kennedy Space Center in September 2009 following the California landing of Discovery. Upon return to KSC, Leonardo was prepared for what would ultimately be its final mission to space as a Multi-Purpose Logistics Module.

Launching into the pre-dawn sky on Monday, April 5, 2010, Leonardo was once again transported to the ISS by Discovery. During the 15-day mission of STS-131, Leonardo was used to deliver food and science supplies to the ISS, the third and final Minus Eighty Degree Laboratory Freezer for ISS, a Window Orbital Research Facility, one Crew Quarters rack, a Muscle Atrophy Resistive Exercise rack, Resupply Stowage Racks, and Resupply Stowage Platforms.

Leonard: From MPLM to PMM:

With the landing of STS-131, Leonardo was transferred back to the Space Station Processing Facility where modifications and reconfigurations began immediately to convert Leonardo for permanent attachment to the ISS.

Some of these modifications included equipment removal to reduce the overall weight of Leonardo. These removals included the elimination of the Active Thermal Components in the forward endcone and the removal of utility plates, harnesses, water ducts, and “associated components from standoff Bays 1 and 2.”

These removals resulted in a net weight loss of 178.10 lbs.

Furthermore, several modifications were made to “facilitate on orbit maintenance,” notes the Mission and Stage Overview MOD FRR presentation available for download on L2.

These modifications included lengthening the forward endcone cable harnesses to allow for “panels to swing open without the need to disconnect multiple cable harnesses” and the inclusion of PIP pin capability in order to “replace non captive fasteners in the interface (will be inserted if we ever have to get to the avionics boxes behind the panels)” since PIP pins do not meet launch load requirements.

Additionally, the Permanent Multipurpose Module (PMM) Leonardo’s software was upgraded to account for the equipment that was removed as part of the MPLM to PMM weight reduction modifications.

“With the decision to remove several components inside PMM as a weight reduction effort, MPLM software was changed to account for the missing hardware,” notes the MOD FRR presentation.

However, several commands in the Mission Control Center will still exist for controlling the missing hardware on PMM Leonardo. This was done on purpose since STS-135 would – if funded – bring up the MPLM Raffaello, as would the STS-335 LON mission.

“Related to the PMM software generation, there are several commands in MCC for controlling that now missing hardware. Note that these MPLM commands were not deleted from the MCC command server to protect for a future flight (135) that may bring up an MPLM.”

STS-133 Specific Articles: http://www.nasaspaceflight.com/tag/sts-133/

Therefore, to protect against the accidental selection and transmission of these commands to the PMM, MCC will “Type A” the commands to protect against this possibility.

Additionally, further modifications to Leonardo included the installation of upgraded MMOD (Micro Meteoroid Orbital Debris) shielding, the addition of a Planar Reflector at the request of JAXA, and the modification of the module’s Multi-Layer Insulation (MLI) to “upgrade the PMM Probability of No Penetration (PNP) to a level commensurate with other ISS modules (0.994).”

For the Planar Reflector, JAXA requested the addition of this component to the endcone area of the PMM to take the place to the reflector that was located on PMA-3 during HTV-1 approach operations. The new reflector will aide HTV-2 and subsequent HTV missions during their approach ops.

Moreover, the MLI upgrades will increase the ability of the PMM to handle potential MMOD impacts. As the MOD FRR presentation states, “If PMM PNP requirement = 0.995, USOS/ESA/JAXA MMOD risk would be 11% lower than if PMM PNP requirement = 0.99.”

In all, the PMM has an effect on the overall USOS/ESA/JAXA segment MMOD risk because of the module’s “relatively high-MMOD risk” due to its berthing location on the ISS. While the nextel/Kevlar MLI reduces the overall weight of the PMM, it conversely increases the MMOD risk. As such, the “PMM with MMOD PNP requirement = 0.99 would be highest risk module/element on USOS/ESA/JAXA.”

Nonetheless, with all of these modifications in place, the PMM Leonardo will add much-needed storage space on the ISS; however, that storage space won’t be available to the ISS crew immediately.

In fact, PMM Leonardo will be launched with a near full load of payloads. Following attachment to the ISS, the contents of the PMM will be emptied to the appropriate locations on ISS. Once JAXA’s HTV2 arrives in February, Leonardo’s now unnecessary launch hardware will be transferred to HTV2 for ultimate destruction in Earth’s atmosphere.

Once the launch equipment and racks have been removed, the PMM will then provide the needed stowage space for the ISS. However, “Activities to reconfigure the PMM following ULF-5 will span multiple [ISS crew] increments and will include relocating science (ER8, Robonaut) and relocating various NASA and ESA items into the PMM (CWCs currently stowed in the JEM, food containers, spares, payload hardware etc.),” notes the MOD FRR Mission and Stage Overview presentation.

In all, Leonardo will gain the distinct honor of being the only non-permanent module for ISS construction to be converted to and left on ISS as a permanent fixture. Even more fitting is the fact that Leonardo will be ferried to space for the final time on Discovery – the Shuttle orbiter on which it has flown the vast majority of its missions.

Images: NASA, Larry Sullivan (NASASpaceflight.com/MaxQ Entertainment/STS-133 FRR Presentations via L2).

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