STS-133 Mission Evaluations:

As reported by this site in June, NASA has already officially baselined the STS-133 mission in the FDRD – a process that converts a mission from assignment planning, into the baseline schedule.

Right now, STS-133 – along with STS-134 – is currently baselined to launch No Earlier Than July 29, 2010 on orbiter Endeavour. However, the Space Shuttle Program (SSP) and the International Space Station Program (ISSP) are discussing the various options available to them, as the SSP draws closer to the end of its current – subject to extension – launch manifest.

As a result, the two programs have tentatively agreed to swap the order of the final two manifested missions – flying STS-134 on Endeavour in July 2010 and slipping STS-133 into mid-September on Discovery.

This process of swapping the flight order will be accomplished via a Change Request (CR) to the PRCB (Program Requirements Control Board). The CR will enable mission planners and flight engineers to adequately prepare for each mission without excessive overlap in mission planning and flight production protection.

In all, the CR has to be approved by October 5, 2009 in order to avoid flight production confliction and ensure that the two missions can meet their respective launch dates.

However, the CR is expected to be approved long before October 5, as both the SSP and ISSP are determined to maximize up-mass potential on the final Shuttle mission to the ISS.

Nevertheless, the order in which STS-133 will fly wasn’t the only special consideration NASA was giving to this mission. In fact, NASA baselined two different versions of STS-133 based on ISS Program and Shuttle program projected needs.

At the time of the baseline into the FDRD, it was unknown which flight option NASA would choose to fly for STS-133, the 12+1 day Multi-Purpose Logistics Module Option (Option 1) or the 10+0 day Permanent Logistics Module mission.

However, the latest Program Requirements Control Board (PRCB) meeting has confirmed that NASA has opted for option 2 – with a modified mission duration capability of 10+1+2 days.

“As you may have heard, the ISSP is interested in increasing upmass as much as possible on this mission, which could possibly be the last mission in the assembly sequence,” noted Tuesday’s MOD 8th Floor News memo on L2.

“One method for doing this would be to reduce the crew size to 5 to reduce the upmass associated with supporting a crew member on orbit. Additionally, the Program agreed to reduce the number of EVA’s to 1 and add an additional rendezvous day (which gives more time for the 5 person crew to accomplish the Shuttle Thermal Protection System inspection).

“Both Programs have now agreed to baseline the mission in this way with a duration of 10 + 1 + 2.”

Under the approved changes to the mission baseline via the updated FDRD presentation on L2, the STS-133 mission will have “the first set of performance enhancements recommended by the STS-133 Tiger Team” incorporated into the mission’s parameters.

As such, the STS-133 orbiter will have its 5th cryo tank set removed, as well as its 6th Gaseous Nitrogen tank, during turn-around processing in its Orbiter Processing Facility.

The Aft winch will also be removed from the orbiter and the LTA cables and now-unnecessary supporting hardware for the Express Logistics Carrier 4 (ELC-4) deleted from the cargo manifest. That is not, however, to say that ELC-4 has been deleted. It will still be an integral part of the STS-133 payload to the ISS.

Furthermore, the Multi-Purpose Logistics Module (MPLM) – either Raffaello, Leonardo, or Donatello – which will fly on STS-133 will be modified and re-designated as a Permanent Logistics Module (PLM) which will be left on the ISS after STS-133 departs.

STS-133 will also see a configuration change to its Solid Rocket Boosters (SRBs). In order to eliminate as much weight as possible to maximize cargo upmass on this mission, the STS-133 SRBs will have their water impact structures and foam, cosmetic paint, water impact foam, and Reusable Solid Rocket Motor Nozzle Severance System removed.

Moving to a five person crew – the minimum number of crew members necessary to adequately and safely perform all the necessary inspection and docking preparation activities in the early days of the mission – has been under discussion for some time, prior to the FDRD update.

As a result of all this upmass savings, the PLM will now be able to carry 3,002lbs more equipment than it would have under Option 1. Efforts to increase upmass availability in the MPLMs were first seen ahead of STS-126.

“Approved the change to the STS-133/ULF5 FRD. Mission will be rebaselined as 10+1 day mission with Flight Day 4 (FD4) rendezvous, Permanent Logistics Module (PLM) which will be left on ISS (not returned via orbiter), 1 EVA and 5-person crew,” added the 8th Floor News.

“EVA task must be stage deferrable and cannot require dual-arm ops in parallel with EVA (single arm ops in parallel with EVA is OK based on crew tasking).

“Going from 6-person to 5-person crew results in an 871 lbm ascent performance gain (including removal of ballast). Additional ascent performance improvements to increase ISS upmass will be reviewed at a later time via separate CR.

“(There is) forward work to identify candidate list of ascent performance improvements. Ascent Performance Tiger Team is scheduled to finalize the list of recommended improvements via an offline meeting on 8/7/09, followed by formal CR review process and PRCB (TBD date).”

The new preliminary mission timeline shows the STS-133 crew conducting the standard OBSS (Orbiter Boom Sensor System) inspections of their Orbiter’s Wing Leading Edge and Nose Cap RCC (Reinforced Carbon-Carbon panels) on Flight Day 2 (FD-2), FD-3 will involve preparations for their arrival at the ISS.

Docking to the ISS will take place on FD-4, with unberthing and transferring the ELC-4 and PLM to the ISS on FD-5. Activating the PLM on FD-6 will be followed by either the only EVA (Spacewalk) or a Focused Inspection of their vehicle’s heat shield on FD-7.

Performing the final middeck transfer to and from the Orbiter and closing the hatches between the ISS and Orbiter will take place on FD-8, with undocking and late-inspection on FD-9, landing preparations on FD-10, and landing at the Kennedy Space Center on FD-11.

However, given the now likely scenario of an extension of the Shuttle Program to 2012 – and the addition of three more Shuttle missions after STS-133 – based on the Augustine Commission’s report to President Obama and Congress, it is unknown if these changes to the STS-133 flight plan will still be incorporated if the Shuttle Program is extended.

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

No related posts.

Vehicle Hardware and Flow Updates:

According to the Delta Launch Site Flow Review (DLSFR), which was held at the end of June for STS-129, Atlantis remains on track to meet all of her processing goals.

The main constraint relates to the health of Atlantis’ Window 5 (pilot window) pressure pane, with evaluations still ongoing into potentially unacceptable damage – following the removal of a work light knob that embedded itself between the window and the dashboard in the flight deck.

A second set of mold impressions on Atlantis’ Window 5 have been ordered for Monday, which are currently “in cure” – per morning processing information on L2.

Evaluations may not be complete until later in the week, with the hope any damage is within acceptable levels for flight. Otherwise the pressure pane may require replacement, resulting in up to a six month schedule impact for Atlantis.

Currently, Atlantis is scheduled to use External Tank 133, Left OMS Pod 04, Right OMS Pod 01, Reusable Solid Rocket Motor set 108, as well as Space Shuttle Main Engines 2048, 2044, and 2058 in the number one, two, and three positions, respectively.

Engines 2048 and 2058 last flew on Discovery during STS-119 while engine 2044 few with Atlantis in May during STS-125.

Currently, Atlantis is tracking toward a rollover to VAB on October 7 for mating to her External Tank. This will be followed by rollout to Pad-A on October 14 ahead of a launch No Earlier Than November 12th at approximately 4:30pm EST.

This mission will mark the first time in nearly two years that Atlantis will visit the International Space Station (ISS), carrying vital upmass to the Station ahead of the retirement of the fleet. 

The last time Atlantis was docked to the Station was during STS-122 (which delivered the Columbus research module for the European Space Agency) in February 2008.

Furthermore, as part of the ever evolving nature of every Shuttle mission, Atlantis’ total launch weight has changed slightly since the Launch Site Flow Review held in April of this year.

As a result of the changing nature of Atlantis’ payload, the vehicle and mission are now expected to have an Ascent Performance Marin of ~625 lbs at launch.

Changes to Atlantis and Flow Processing Turnaround:

Furthermore, since Atlantis’ return to KSC following a landing at Edwards Air Force Base, CA on STS-125, engineers and mission planners have conducted a thorough review of Atlantis and all the work items that were baselined/scheduled for the OPF flow leading to STS-129.

As a result, the DLSFR noted several additional modifications that will be made to Atlantis as well as modifications and deferrals of some work items until the Orbiter’s next OPF flow later this year.

The first such modification listed in the DLSFR is the partial deferral of the Air Duct Clamp and Cushion inspection and modification.

“Program approval is requested to partially defer baselined modification record until access is available for implementation,” notes the 122 page STS-129 DLSFR document available for download on L2.

The three issues leading to this modification were the observance of a missing clamp form a flex duct, “two cushions installed but not shown on the drawing, and two cushions installed per drawing, but installation documentation not located.”

The first two issues were noted during return to flight processing on Atlantis for STS-115. However, after evaluations showed that the discrepancies would not affect flight performance, a form was written to “correct the engineering discrepancies” and defer work on the area to the next available period of access.

Originally, this access would have come during Atlantis’ flow between STS-125 and STS-129. However, the OPF flow for STS-129 was shortened considerably when STS-125 was delayed from October 2008 to May 2009.

The extra time in the OPF before STS-125 in May 2009 allowed engineers to perform several get ahead tasks on Atlantis – thereby shortening the amount of time she would have to spend in the OPF before STS-129.

Currently, the access engineers do have to the area is not enough to verify the part numbers of the cushions that are installed. As a result, flight rationale is being worked on at this time to, once again, defer work on these discrepancies.

The second item noted by the DLSFR is for two technical order changes: one to a GN2 (gaseous nitrogen) Purge Line Installation and the second to a Mission Kit associated with the SSPTS (Station to Shuttle Power Transfer System).

For the GN2 Purge Line, the presentation notes that the line was “required for STS-125 HST mission to provide GN2 purge line to the Super Lightweight Interchangeable Carrier (SLIC) and the Orbital Replacement Unit Carrier (ORUC).”

The tech order change notes that the purge line will remain installed on Atlantis because it is located below the payload bay liner and will not interfere with vehicle or payload operations during STS-129.

Secondly, a tech order change was also initiated to remove a mission kit and its associated hardware from Atlantis.

The mission kit was originally designed to support the installation of SSPTS onto Atlantis. However, since Atlantis will no longer be receiving a SSPTS, the mission kit is not applicable anymore.

The next major modification for Atlantis is the development of a new Tyvek Rain Cover for FRCS (Forward Reaction Control System) thruster positions F3D and F4D.

This redesign is expected to “prevent tearing/partial cover release” during the initial seconds of liftoff.

The partial release of several FRCS thruster covers has occurred on a handful of Shuttle missions.

“During STS-119, the remnant (FRCS thruster cover) was estimated from imagery to be 6-10 grams which was larger than remnants from previous flights,” notes the DLSFR.

The new design, dubbed a Rain Cover Plug (RCP), will be smaller and installed deeper in the thruster.

Final approval for this new thruster cover is still pending. However, the review document notes that the final presentation on risk mitigation via the new design was to be presented to the Orbiter Project Office around June 26th.

In addition to these modifications, several other enhancements are being made to Atlantis this flow.

As previously reported by this site, these modifications include: Middeck ISS Payload Cooling Requirements, Rudder Speed Brake Inconel Thermal Barrier Redesign, Oxygen Crossover Valve Signal Talkback Modification, Relocation of D-Hatch Actuator Handle Position Decal, External Airlock Ducting Configuration Change, OMS Pod Micro-WIS Strain Recorder Removal, and Acreage Doublers Addition to Avionics Bays 4, 5 and 6.

Additional Work:

In addition to modifying Atlantis, engineers are also conducting a series of Wing Leading Edge (WLE) spar inspections.

Structural inspections of the Wing Leading Edge spars are due prior to the last manifested flight of OV-104 (due date January 22, 2010 with final flight currently manifested for May 2010).

However, the performance of these inspections (a total of 22 WLE panels per wing on Atlantis) is a very intrusive process and a “significant flow impact” that is necessary to maintaining the safety of the Orbiter fleet.

In order to accommodate both the spar inspections and the desire to fly Atlantis past January 22, 2010, engineers have developed a series of mini spar inspections that can be performed within the standard OPF flows.

In fact, during Atlantis’ second stay in the OPF before STS-125, engineers began these spar inspections – leaving only 16 panels on each wing remaining.

However, the Program Design/Director’s Review Resources Team has determined that, for safety matters, all of Atlantis’ spars have to be inspected by January 22, 2010.

Currently, the plan is to inspect the spars of four panels per wing – down from the originally planned six panels per wing – during this current flow.

Following the results of the spar inspections from this flow and the flow prior to STS-125 in May 2009, the Orbiter Project Office will determine if “an exception to the requirement to complete the spar inspection before January 22, 2010 can be created without compromising vehicle and crew safety.”

The presentation did not mention whether this exception would include the option of not inspecting some of the spars or simply allowing the final spar inspections to take place in February and/or March 2010.

Furthermore, engineers and program officials are also waiting on post-flight measurements of “prevailing torque on Endeavour’s multi-flight windows” before clearing a potential issue with Atlantis’ multi-flight windows.

Windows one and six on Endeavour were torqued at Pad-B (during STS-400 processing) before their first flight, notes the DLSFR document.

An adverse finding on post-flight measurements could raise concern for Atlantis# multi-flight windows modification locations and could lead to a request to retorque the windows.

Based on a mid-July launch date of Endeavour on STS-127, post-flight measurements would be expected sometime in the August timeframe – well within the “need date” for STS-129.

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

No related posts.

Opening Information:

Right now, STS-133 – along with STS-134 – is currently baselined to launch No Earlier Than July 29, 2010 on orbiter Endeavour. However, the Space Shuttle Program (SSP) and the International Space Station Program (ISSP) have, for some months now, been discussing the various options available to them as the SSP comes to an end.

As a result, the two programs have tentatively agreed to swap the order of the final two manifested missions – flying STS-134 on Endeavour in July 2010 and slipping STS-133 into mid-September on Discovery.

The first category relates to performance enhancement strategies that should be pursued. These include reducing the STS-133 crew to five people, reducing mission duration to less than 12 days, removing fifth Cryo Tank Set and eliminating ballast, removing 6th GN2 Tank, and deleting ELC-4 LTA cable and associated hardware from the mission’s baselined payload.

The second category, which includes suggestions that “make sense but need more analysis/shelf life considerations,” includes such performance enhancements as reducing rendezvous altitude of Station and Shuttle, removing Aft Radiator Panels from Discovery, and performing a multistage Deorbit Burn at the end of the mission.

Finally, the third category (options that “are not thought to be good candidates for pursuit because of cost, schedule, risk, low return for magnitude of effort/distraction”) include throttling the Space Shuttle Main Engine’s from 104.5 percent to 106 percent during ascent and removing SRB parachutes and cameras.

These options were briefed by the Tiger Team to the Joint Mission Integration Control Board and the SSP Control Board with the knowledge that the Category-1 recommendations are being incorporated into a second CR for STS-133.

Furthermore, the FDRD notes that “CR-2 updates will be familiar to most, but not all reviewers, due to the support that has been provided to the Tiger Team. Therefore an expedited review is being requested for CR-2 in order to facilitate including updates in integration work.”

As of now, the Tiger Team has been tasked with reporting their final assessments of all Category-2 recommendations to the SSP and ISSP no later than mid-July. Any accepted recommendations from that meeting will then be presented to the “STS-133 Flight Integrated Product Team for integration into the STS-133 mission.”

STS-133 – Option 1:

The first option for STS-133 will see Discovery launch with five Cryo Tank sets, six GN2 tanks, and a six person crew on a 12+1 day mission with one baselined EVA (Spacewalk).

Further, Discovery’s primary payload – in addition to the DoD payloads of opportunity – would be a Multi-Purpose Logistics Module (MPLM) and the Express Logistics Carrier 4 (ELC-4).

For the MPLM, four active longeron latches, one active keel latch with keel camera, and a Remotely Operated Electrical Umbilical (ROEU) that will provide 28V heater power and 124V of temperature and pressure checks will be used to install the module into Discovery’s Payload Bay.

Inside the MPLM will be two Utilization racks, three Resupply Stowage Platforms, and two Resupply Stowage Racks.

ELC-4 will have four active longeron latches for the deck assembly and two passive longeron latches and one passive keel latch for the Keel Assembly.

A ROEU will provide 28V heater power to the ELC and a Payload Power Switching Unit (PPSU) will provide additional electrical inhibit capability.

ELC-4 will also require “unique Flight Software for the PPSU’s internal heater on/off telemetry.”

Furthermore, the payload that will be attached to ELC-4 for launch (under option 1) will be the HPGT, a SARJ Race Ring, a spare Express Pallet Controller Assembly, and FRAM based SASA ORU-2, CTC-2, and four empty Passive FRAM sites.

Additionally, Discovery will carry a GLACIER freezer to the ISS and return a used GLACIER to Earth. Also, Discovery will deliver a Commercial Generic Bioprocessing Apparatus/National Lab Pathfinder (CGBA/NLP) to ISS.

In all, Discovery’s expected payload weight is ~35,461lbs with an additional 1,326lbs of ballast in the aft. The MPLM is expected to weigh 18,304lbs, ELC-4 9,516lbs, and the middeck payload 7,591lbs. That leaves an overall Ascent Performance Margin of ~800lbs.

Overall, the mission objectives for STS-133 are to “deliver utilization, logistics, and resupply, deliver and install ELC-4 to S3 Lower Inboard, deliver spare HPGT and transfer to ELC-2 for stowage, and install the Functional Cargo Block Power Data Grapple Fixture.”

The preliminary mission timeline for Option 1 shows Discovery docking with the ISS on FD-3 (Flight Day 3), EVA-1 (HPGT transfer and ELC LTA cable activities) occurring on FD-4 along with ELC-4 unberth and installation to ISS, MPLM unberth and installation to ISS on FD-5, Focused Inspection activities and middeck transfer operations on FD-6, rack transfers to and from the MPLM on FDs 7-10 with MPLM rebirth in Discovery’s Payload Bay on FD-10, Undocking and flyaround on FD-11, and landing on FD-13.

Option 2:

In a desire to maximize upmass to the ISS, Option 2 for STS-133 incorporates the Category-1 recommendations of the Tiger Team as presented in June to the SSP Control Board.

To this end, under Option-2, Discovery would launch ELC-4 and a Pressurized Logistics Module (modified MPLM for long-duration on-orbit stay) to the ISS.

Discovery would launch with only four Cryo tank sets and five GN2 tanks for a 10+0 day mission with only five crew members and one contingency/deferrable EVA.

For this option, Discovery’s total payload weight would be 38,193lbs – with the Pressurized Logistics Module weighing 21,502 lbs, ELC-4 weighing 9,680 lbs, and the middeck payload weighing 7,011 lbs.

This would give the mission an approximate Ascent Performance Margin of 839 lbs with only 126 lbs of ballast in the aft.

For this option, the ELC-4′s payload would be an Heat Rejection (Sub) System radiator, CTC-2, and two empty FRAMs only.

The Pressurized Logistics Module – which would remain on the station after Discovery’s departure – would carry two International Standard Payload Racks and a To Be Determined Cargo Rack Equivalent compliment only.

The mission’s objectives would be the delivery and installation of ELC-4 to S3 Lower Inboard, the delivery and installation of the Pressurized Logistics Module to a To Be Determined location, and the capability for one deferrable EVA if a Focused Inspection should be required.

Under this option, Discovery would dock on FD-4, berth the ELC-4 and Pressurized Logistics Module to the ISS on FD-5, activate and ingress the Pressurized Logistics Module as well as conduct middeck transfers on FD-6, perform the only EVA or Focused Inspection on FD-7, Undock on FD-9, and land on FD-11.

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

No related posts.

Opening Assessments:

Assuming no major shake-ups to the flight manifest – and the approval of the expected CR – STS-134 will be the 133rd flight of the Space Shuttle Program (SSP) and the 25th and final voyage of the orbiter Endeavour, which began service in May 1992 on STS-49.

Carrying an ISS mission designation of ULF-6 (Utilization and Logistics Flight 6), STS-134 was officially baselined into the Flight Definition and Requirements Document (FDRD) on June 25 – initiating production of flight processes to support a No Earlier Than launch date of July 29, 2010. (STS-133 and STS-134 baseline presentations available on L2).

However, should the CR be denied, STS-134 would then be flown by orbiter Discovery in mid-September 2010 and subsequently become the final flight of the Space Shuttle Program. If this were to happen, Endeavour would be given the STS-133/ULF-5 flight to deliver, among other things, a Pressurize Logistic Module to the ISS in the July 2010 launch window.

In all, the official approval of the CR needs to come prior to October 5, 2009 in order to prevent flight production and training requirements confliction for STS-134 and STS-133. However, the CR is expected to be approved long before that date based on ISS requirements and a desire to maximize up-mass on the final Shuttle flights to the orbiting research laboratory.

For STS-134 (launching in July 2010), orbiter Endeavour will use External Tank-137, SRB BI-144, and Reusable Solid Rocket Motor set 112.

The mission, which will also serve as the rescue flight for STS-132 (which, at this time, is scheduled to use orbiter Atlantis with a targeted launch date in May 2010), will be a 12+1+2 day flight with 3+1 EVAs (Spacewalks), with a total of six crewmembers.

Among the multitude of payloads Endeavour will carry to orbit with her are the Alpha Magnetic Spectrometer 2 (AMS-02), Express Logistics Carrier 3 (ELC-3), Materials on International Space Station Experiment 8 (MISSE 8), an Orion Rendezvous Detailed Test Objective (DTO) kit, and a GLACIER freezer module for one of the Station’s science laboratories.

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

Also, Endeavour’s crew will leave the OBSS (Orbiter Boom Sensor System) on the ISS to allow the following Shuttle crew to use the inspection boom once they reach the Station, as previously revealed by this site.

The desire to leave the OBSS on the ISS for the STS-133 crew (and future ISS expeditions) relates to the desire to gain as much up-mass potential as possible for the final scheduled Shuttle flight.

Also, leaving the OBSS behind after the completion of the Shuttle program will provide a work tool or platform for future ISS expeditions should a repair of one of the Station’s solar arrays (or similar issue) require the use of a platform to extend the working capability/reach of the Station crew.

Payload Overview:

Given the rather large payload up-mass for Endeavour’s mission – totaling 36,740lbs of payload (including middeck payload and crew equipment weight) – the FDRD baseline of the STS-134 mission details several specific notes about each of the mission’s primary payloads.

For AMS-02 – weighing 15,300lbs – the mission planning document notes that this payload will have four longeron payload latches and one active keel latch for its attachment to the payload bay sidewalls of Endeavour.

Additionally, once on orbit, Remotely Operated Electrical Umbilicals (ROEU) will provide AMS-02 with 124V of power for its heaters and avionics. Prior to liftoff, this power will be provided via the T0 umbilicals on the launch pad.

These T0 umbilicals will also allow launch personnel to monitor the health of AMS-02 prior to liftoff and make sure that Launch Commit Criteria for the AMS-02 are not breached.

The AMS-02 unit, which up until about a year ago was without a ride to orbit until the United States Congress mandated its addition to the Shuttle manifest, will be attached to the Starboard 3 Upper Inboard Command Attach System (CAS) on the ISS.

According to the baseline document, the AMS-02 unit is a “particle physics detector” which contains a large, cryogenic super-fluid helium superconducting magnet. The AMS-02 unit is designed to “search for antimatter and the origin and structure of dark matter.”

Furthermore, the baseline notes that AMS-02 is a complex payload that will require significant testing and payload processing before liftoff.

The payload will also require significant “power usage and data downloads after launch until deployment from the Payload Bay,” notes the baseline document – available for download on L2.

The second primary payload (ELC-3) will also have four active longeron latches as well as two passive longeron latches and one passive keel latch.

A ROEU will also provide ELC-3 will 28V of electricity for its heaters. A Payload Power Switching Unit will provide additional electricity and inhibit ability as needed for ELC-3.

Additionally, ELC-3 will be attached to the Port 3 Upper Outer CAS on ISS. With ELC-3, NASA will continue its effort to bring as many spare components to the ISS as possible before the retirement of the Shuttle fleet.

Attached to ELC-3 will be an Ammonia Tank Assembly, a Special Purpose Dextrous Manipulator Arm with Orbital Replacement Unit change-out mechanism, a spare ELC pallet controller avionics box, S-Band Antenna Sub-System #2 & 3, High Pressure Gas Tanks, and Space Test Program Houston 3 Department of Defense payload.

In addition to this manifested and baselined payload on ELC-3, the ISS program is looking at an additional 1,481lbs of payload that they would like on ELC-3 – payloads that are currently not listed on the mission baseline or accounted for in the mission’s up-mass weight.

The Baseline further notes that the deployment and attachment of ELC-3 must be accomplished prior to any activities with AMS-02 since “Orbiter is not protecting for the worst-case forward ballast scenario which would result in a contingency undocking and landing.”

Finally, the Orion Rel-Nav Sensor (DTO 703) will be mounted on the Orbiter Docking System (ODS) in Trajectory Control Sensor slot 1 and on an Adaptive Payload Carrier in bay 3 port of the Payload Bay.

“28 VCD for heaters and operation, GMT timing signal, Ethernet and RS-422 for command and telemetry via Payload General Support Computer” will be provided for this DTO.

For the Orion Rel-Nav Sensor DTO, Endeavour will fly a nominal Orbiter trajectory to and from ISS Pressurized Mating Adaptor-2.

The docking target on the ISS will be enhanced with reflectors to allow for the characterization of the Orion Rel-Nav sensors’ performance during rendezvous and proximity operations with the ISS.

These proximity operations will be tested during approach and docking, undocking, flyaround (time-permitting), and fly-out from the ISS.

In all, with all payload weight accounted for in the baseline and the time of year STS-134 is scheduled to launch in, Endeavour will have an Ascent Performance Margin of just 800lbs. Of course, this number will change as refinements to the mission and its payload are made in the coming months.

Additional Mission Objectives:

Once docked at the ISS, Endeavour’s crew will be tasked with the transfer of several hundred pounds of equipment from the Shuttle’s middeck to the ISS, and visa versa.

The primary middeck payload that will be hauled over to the ISS is the General Laboratory Active Cryogenic on ISS Experiment Refrigeration (GLACIER) unit.

Endeavour will carry one new GLACIER unit up to the ISS and return two GLACIER units to Earth.

Furthermore, in addition to installing AMS and ELC-3 to the external structure of the ISS, Endeavour’s crewmembers will be tasked with several other operations during the mission’s three baselined EVAs.

These EVA activities include cleaning and lubricating both the port and starboard Solar Alpha Rotary Joints (SARJs), transferring MISSE 7a and 7b (located in their Passive Experiment Container) from ELC-2 to Endeavour’s Payload Bay, and attaching MISSE 8 and a Power Data Grapple Fixture (PDGF) to the ISS.

Tasks will also include installing the OBSS onto the S1 Truss On-Orbit Support Equipment stanchions – a piece of equipment that was previously used to house the OBSS on the station in between the STS-123 and 124 missions in 2008.

Because the OBSS will be left on the ISS, the STS-134 crew will have to perform the customary late-inspection of Endeavour’s RCC Wing Leading Edge panels and Nose Cap before undocking from the Station.

This operation has been performed before on STS-123 before that crew also left the OBSS on the Station.

Following undocking, Endeavour’s crew may perform several payloads of opportunity — the aforementioned MAUI, SEITI, SIMPLEX, and RAMBO-2.

Preliminary Flight Plan:

Launching on Flight Day 1 (FD-1), Endeavour’s crew will spend FD-2 performing the now-standard post-launch inspection of Endeavour for any damage the vehicle’s TPS (Thermal Protection System) might have incurred during liftoff.

After docking with the ISS on FD-3, Endeavour’s crew will remove the ELC-3 from the payload and berth it to the ISS while also conducting transfer operations from Endeavour’s middeck to the ISS.

FD-4 will see the deployment of AMS-02 from Endeavour and installation to the ISS.

EVA-1 will be performed on FD-5 – a spacewalk that will see the transfer of MISSE 8 to the ISS and the return of MISSE 7a and 7b from ELC-2 to Endeavour.

FD-6 will see any Focused Inspection work deemed necessary by imagery analysts on the ground as well as a Water Dump from Endeavour. This will be followed on FD-7 by EVA-2 – the cleaning and lubrication of the Port and Starboard SARJs.

FD-8 will see the crew perform the docked late-inspection of Endeavour with the OBSS before transferring the boom to the S1 truss of the ISS the following day during EVA-3. EVA-3 will also see a pair of spacewalkers install the PDGF to the ISS.

FD-10 will be an off-duty day for the crew as well as the stowage of the two GLACIER units for return to Earth. Also, at the end of FD-10, the hatches between Endeavour and the ISS will be closed for the final time.

Endeavour and her crew will undock on FD-11, perform the standard pre-landing checkouts of the Flight Control System and Reaction Control System for a landing at the Kennedy Space Center on FD-13.

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

No related posts.

STS-400/127 Processing Latest:

With Atlantis/STS-125 sat on Pad 39A - and on track for a May 11 launch to service the Hubble Space Telescope (HST) - younger sister Endeavour is being processed to a point of readiness as the STS-400 LON shuttle – in preparation for the highly unlikely and undesirable requirement of launching a rescue mission.

Once stood down from the LON requirement, Endeavour will be rolled from Pad 39B to 39A, for final processing ahead of her primary mission, STS-127.

Tracking a NET (No Earlier Than) launch date of June 13, Endeavour will deliver her primary payload of the Japanese Experiment Module – Exposed Facility (JEM-EF) and the Japanese Experiment Logistics Module – Exposed Section (ELM-ES) to the International Space Station (ISS), on what is expected to be a 16 day mission.

Processing has been relatively trouble free, with only the fleet-wide issue with the ET Umbilical Well Camera Flash system being worked, along with a data transmittion issue with her Space Shuttle Main Engines (SSMEs).

“The blank-off plates were installed in preparation for helium signal testing. Communication system validation worked,” noted KSC Integration’s latest report, via L2. “Preps for the hypergolic load have begun, mating the OMS and FRCS QDs (Quick Disconnects). The hypergolic load will be next Tuesday night. Troubleshooting of the ET camera is ongoing.

“Unable to transmit Main Engine data to the ground using FM System 2. Signal was nominal previously with the FM system. Initial troubleshooting, switching from RF to T-0 data, has again passed with FM1 and failed with FM2. Additional troubleshooting will require access to AV Bay 3A to evaluate the FM Signal Processor and Transmitter path.”

Weekend work has been focusing on the preparations for Prelaunch Propellant Servicing (S0024), while engine and aero surface flight readiness testing (V1046), Ball Seal leak checks, and helium signature tests have been completed.

The close proximity between STS-125 and STS-127 will challenge managers and engineers, with the need to safely conclude Atlantis’ mission, and review any IFAs (In Flight Anomalies) from STS-125 - which are subsequently used in the next mission’s Flight Readiness Reviews (FRRs) - ahead of STS-127′s launch.

In order to ensure STS-127 isn’t held up during the IFA to FRR overviews, managers will meet while Atlantis is still on orbit to review her IFAs. Usually the IFA review is conducted around three weeks after landing.

“The IFA Review for STS-125/HST-SM4 is likely to be held at the May 21 SSP PRCB (Program Requirements Control Board) meeting, while the mission is still in progress,” noted the latest Shuttle Stand-Up/Integration report on L2. “This time-crunch is due to the FRR for STS-127/2JA that is planned for the last week in May.”

“The STS-127/2JA FRR dates are being worked. The goal is to avoid an SSP FRR for the last week in May, but the first week in June is not much better,” added Mission Management Team (MMT) manager Mike Moses. “The hard date should be published by the time the (Agency) STS-125/HST-SM4 FRR is held (this coming Thursday).”

STS-128 Processing Latest:

The pace doesn’t let up after the STS-127 mission is complete, with Discovery back in action following STS-119 for her August 6 launch date on STS-128. A recently proposal to delay the mission by around a week was turned down.

Discovery will be prepared for a 13 day, three EVA mission to the ISS that will include the flight of the TriDAR AR&D Sensor Detailed Test Objective (DTO), the next Boundary Layer Transition (BLT) DTO, and the first flight of the OI-34 flight software.

The primary payload will be the MPLM (Multi-Purpose Logistics Module) Leonardo – returned from the highly successful STS-126 mission in November - and the Lightweight Experiment Support Structure Carrier with an Ammonia Tank Assembly.

Discovery’s Orbiter Processing Facility (OPF-3) is a busy place, with various work focusing on the removal and reinstallation of the RMS (Remote Manipulator System) robotic arm – following a latching issue, replacement of flight deck windows, work on a right hand ET door actuator, and engineering efforts on a Forward Reaction Control System (FRCS) thruster.

“The right-hand ET door PDU was completed, along with changeout of the left-hand ET door umbilical retract actuator,” noted KSC Integration (L2). “Window 6 has been R&R’d and Window 7 is complete. On the FRCS, the F5R thruster removal has revealed a broken mounting stud. Repair techniques are being evaluated.”

JSC’s Orbiter Project Office (United Space Alliance) expanded on the thruster issue, relating to a missing stud, which will need to be found – or written off as a non-concern – ahead of flight.

“On OV-103 (Discovery), during R&R of the F5 hard on the HMF (Hypergolic Maintenance Facility), one of the studs used to hold the jet in place was broken and the net was missing,” noted OPO (L2). “The team is now searching to determine what happened to the stud/net. Root Cause Analysis is underway to understand this issue.”

On the ET door actuator and RMS, OPO added: “Testing was performed this week on the ET umbilical actuator on OV-103 that failed to retract. It has been determined that the failure mode was not as critical as some thought – it did not fully retract, but it was locked in place. Internal leakage within the actuator is the most likely cause of this failure.

“Regarding the RMS on OV-103, the RMS was removed and the shoulder-brace collet has been inspected. The results are within range of what has been seen in the past. This has been reinstalled on the vehicle, with no additional work needed or expected for the STS-128/17A flight.”

Also noted by the OPO engineers this week was a debate on whether to inspect an attach point on Discovery’s right OMS pod – which is routine, as opposed to being related to an issue with the hardware

“A tag-up was held with OPO. The need to remove the right OMS pod to inspect attach point 2 on OV-103 was discussed. A torque check on this attach point was planned for this flow.

“The concern is that performing this work could extend the flow, affecting the remaining flights scheduled. The full story for and against performing this work will be presented at a Noon Board next week.”

Discovery’s flow, referenced above, is proceeding on the timeline, with several milestones due over the coming month. First up will be the arrival of STS-128′s External Tank (ET-132), which is being processed ahead of the timeline at the Michoud Assembly Facility (MAF) in New Orleans.

“ET-132: Work is proceeding nominally. The nose cone is on, the intertank door is wrapped up, the aft hardware is being worked, and everything is proceeding ahead of schedule,” noted a Lockheed Martin update (L2) this week. “The ECD (Expected Completion Date) for this work is now April 28 – this supports the NASA request for the tug to show up May 1.”

The orbiter will also receive her SSMEs around June 1, with one engine (2048) being reinstalled on Discovery after flying with her on STS-119.

“In the Engine Shop, Engines 2048, 2051 and 2058 – removed from the last flight – have been rotated to the vertical workstands,” noted SSME Pratt & Whitney Rocketdyne/KSC’s latest report (L2). “Engine 2048 will undergo a quick turnaround, as it is allocated for use on STS-128/17A; the installation date is June 1.”

Additional work on Discovery’s Main Propulsion System (MPS) plumbing – via the addition of a doubler plate on the three 90 degree elbow bends immediately downstream of the Flow Control Valves (FCVs) – remains on hold, pending the performance of the valves on the next two flights.

Click here for NASASpaceflight.com articles on the FCV issue since STS-126.

Engineers are growing in confidence with their flight rationale effort ahead of STS-119, following a liberation event from one valve’s poppet lip on STS-126. However, the doubler will be ready for its debut on STS-128, should it be required. Managers have already decided against its installation on STS-125 and STS-127.

“There was a discussion on the need to continue development of a doubler for the FCV line elbow immediately downstream of the FCV,” noted the latest Stand-Up. “Testing of the doubler is nearly complete.

“Based on flight rationale showing poppet valves inspected to the best of our ability, there does not appear to be a compelling need to install the doubler – the testing will be completed, with the hardware ready if needed.

“The subject of thicker elbows is a more complex modification; it provides better protection than the doubler, but if the doubler is not needed, then the thicker elbows certainly are not. These could not be installed in time for the STS-128/17A flow. This topic is also on hold.”

The latest PRCB meeting also outlined the overall status of processing and mission preparation via an impressive 106 page Delta Launch Site Flow Review presentation (available to download on L2). The presentation will be turned into an article in the near future.

STS-129 Processing Latest:

Currently targeting launch No Earlier Than November 12, 2009, the STS-129 mission will see Atlantis deliver the Express Logistics Carriers 1 & 2 (ELC-1 and ELC -2), along with SASA and MISSE (Materials on International Space Station Experiment) 7A and 7B, to the Space Station.

This mission also underwent the Launch Site Flow Review at a PRCB meeting earlier this month, highlighting numerous post-HST modifications that will be conducted on Atlantis.

Processing for this mission is already at an advanced stage, via the missions booster set build-up at the Rotation Processing and Surge Facility (RPSF) at KSC, and External Tank processing at MAF.

“SRB/RSRM: Booster Integration (BI-140)/ Reusable Solid Rocket Motor (RSRM 108)/ (RPSF): Nozzle Back Fill RTV skim coat ready-to-work,” noted processing updates on Friday (L2). Stiffener Ring Closeout RT-455 application in work.

“Aft IEA Cover Installation. Picked up issue for broken bolt during cover installation. Drilled out broken bolt, tapped hole. Paint touch-up I/W. Nozzle Severance Cable Closeout RT-455 in cure. Systems Tunnel Cover Closeout RT-455 application in work.”

Atlantis will fly with ET-133, which is also ahead of schedule – another major achievement by MAF on all recent and downstream tanks, following major schedule challenges in the years following Return To Flight.

“ET-133: In Final Assembly, work is proceeding slightly ahead of schedule,” noted MAF’s status on the tank. “All of the pressurized lines have been installed, all of the lower IFRs (Ice Frost Ramps) have been poured, the aft interface is installed, and seven of the upper IFRs have been poured. Preparation for the final bipod sprays are in work.”

Atlantis was set to receive a wiring modification on a Remotely Operable Electrical Umbilical (ROEU), following lessons learned from Endeavour’s STS-126.

“On Flight Day 13 (FD-13), during the mate, latch, relax sequence operation which is part of the ROEU mate procedure to MPLM (Multi-Purpose Logistics Module), phase C of the ROEU AC arm drive motor associated with system 2 (AC2) did not draw the expected current,” note a PRCB presentation relating to the STS-126 issue.

“Plots showed that the arm drive motor AC 2 phase C had a current draw of ~0.08 amps instead of the expected current of 0.24 amps.”

According to the FO&I (Flight Operations and Integration) office, the low amp draw of arm drive motor AC 2 phase C was compensated for by phase A & B of the same motor. When compared with the demate and stow operations performed on FD-4, the FO&I discovered that the signatures were identical.

The problem was not an issue for the remainder of the Endeavour’s mission, as the ROEU was properly mated to the MPLM and in a good configuration for landing. All power and data lines were correctly connected to the MPLM and all necessary information for the crew about the MPLM was confirmed through a pressure check of the MPLM later in the mission.

Nevertheless, since the cause of the ROEU failure is unknown, “testing and evaluations of wiring and motor will be necessary to determine cause of failure and any fixes,” noted the FO&I.

However, further discussions have determined that no work is required, which would have been part of STS-129′s flow.

“At the FOICB (Flight Operations and Integration Control Board) meeting on April 20, an IFA regarding the STS-126/ULF2 ROEU was closed with good flight rationale. A safety briefing was discussed regarding two inhibits for contingency EVA where the ROEU did not drive and the crew would have to perform this maneuver manually.

“This was dismissed as a non-issue, as there exists a six fault protection before exposure to open metal would occur. Wiring changes on STS-129/ULF3 are not required.”

STS-130 Processing Latest:

Tracking a February 4, 2010 launch date, STS-130/20A, will see Endeavour deliver Node-3 with Cupola to the ISS – thereby installing the final US module and workstation to the ISS.

The mission will carry various 20A specific middeck payloads, as well as SIMPLEX, MAUI, and SEITE, for the recently amended 12+1 day mission.

“This mission will install Node 3 with the Cupola at the Node 1 port location and then relocate the Cupola to Node 3 nadir. Several racks will be transferred from other locations and installed in Node 3,” outlined MOD’s 8th Floor (L2) overview of the mission when it was baselined.

“There are three EVAs planned to support Node 3 installation, Cupola relocation, and Node 3/Cupola outfitting. The mission was originally planned as an 11 day mission. However, the crew office recommended adding an additional day so that EVA 1 can be moved to FD5 to provide additional time to prepare for the spacewalk.

“Beginning EVAs on FD5 is a general crew office recommendation, which can be accommodated on this mission,” added the 8th Floor. ”Therefore, the mission was baselined as a 12 day mission.”

Flying with Endeavour will be External Tank ET-134, which is starting to come together at MAF, with the mating of the LOX and LH2 tank taking place over the past couple of days.

“ET-134: The H2 tank is in Cell A. The LOX tank and intertank were moved over on Wednesday to begin mating operations,” noted the latest MAF status. “The crossbeam is being prepared.”

This mission also received attention from last Thursday’s PRCB meeting, via a 68 page Integrated Launch Site Requirements Overview presentation (available to download on L2).

STS-131 Processing Latest:

Discovery’s STS-131/ISS-19A flight is currently manifested for March 13, 2010, on a 12+1, three EVA mission.

The STS-131 mission will deliver supplies to the ISS via the Multi-Purpose Logistics Module (MPLM) Raffaello and the Light-weight Multipurpose Experiment Support Structure Carrier (LMC).

Secured inside the MPLM will be Zero-G stowage racks, an EXPRESS rack, a Muscle Atrophy Resistive Exercise (MARES) unit, a Window Orbital Research Facility (WORF), one Crew Quarters Rack, a Minus 80 deg Laboratory Freezer for ISS (MELFI), Resupply Stowage Racks (RSRs), as well as Resupply Stowage Platforms (RSPs).

Discovery will also be carrying a LMC with the Ammonia Tank Assembly (ATA) and Passive Flight Releasable Attachment Mechanism (PFRAM).

“No crew rotation is planned for this flight. Mission duration is 12+1 days with 3 planned EVAs for S1 ATA R&R, S0 Rate Gyro Assembly (RGA) R&R, ESA SOLAR payload retrieval, and JEM Seed experiment retrieval,” the MOD 8th Floor outline noted.

“Flight crew is CDR/Alan Poindexter, PLT/James Dutton, MS/Clay Anderson, Rick Mastracchio, Dorothy Metcalf-Lindenburger, Stephanie Wilson, Naoko Yamazaki. There was discussion at the FOICB on this topic to increase the mission duration to 13 days, which would allow for additional transfer time and EVA1 on FD5.

“At PRCB, it was agreed to baseline as a 12+1 day mission and allow the team to evaluate further whether it makes sense to add a day to the nominal mission duration. Since 17A is a very similar flight, lessons learned from that timeline can be factored into the mission duration decision.”

The mission will use External Tank ET-135 and Reusable Solid Rocket Motor set 110 as well as Orbiter flight software OI-34. The latest flight software upgrade.

“ET-135: The LO2 IFRs are being worked,” noted MAF status, with previous status reports noting the tank is on schedule. “The trim work is being performed for the H2 tank. The crossbeam is being prepared for movement.”

STS-132 and STS-133 Latest:

STS-132 will mark the 32nd and final “scheduled” flight of Space Shuttle Atlantis. Targeting launch No Earlier Than (NET) May 13, 2010, STS-132 has been baselined as an 11+1+2 day mission, with three scheduled EVAs (spacewalks) and the option to add an extra EVA should the need arise.

For launch, Atlantis will use External Tank ET-136, Solid Rocket Booster set BI-143, and Reusable Solid Rocket Motor set 111. Atlantis will also fly with the OI-34 operating software.

To accomplish all of the mission’s objectives, Atlantis will carry the Russian Mini Research Module-1 (MRM-1), the Integrated Cargo Carrier – Vertical Light Deployable (ICC-VLD) with several assorted payloads, along with a sidewall SPA Beam payload.

STS-133 was originally manifested as carrying two ELCs (EXPRESS Logistics Carriers), before being realigned to ELC-4, along with a MPLM – likely to be Leonardo – making up the vacant payload space/mass.

The mission is currently working to a NET of July 29, 2010, flying with Endeavour and using ET-137. This flight is yet to undergo the baselining process.

Both missions are continuing to undergo crew size evaluations, with strong indications from the Astronaut Office that both flights need to avoid flying with a crew size of five – as preferred by the International Space Station Program (ISSP).

“Working issues with ISSP regarding a possible reduction of crew members on STS-132/ULF4 and STS-133/ULF5. Strong justification exists that shows a crew of less than six will not be able to accomplish the mission goals,” noted JSC’s Flight Crew/Astronaut Office (L2) on Thursday.

“Wednesday was the STS-133/ULF5 template selection meeting. There will be two EVAs on this mission, with 17 weeks of training required. An 18-week template will be baselined to cover the potential of EVA growth.

“Reducing the crew to five would invalidate the training template; if the ISSP continues with this desire, it will have to be presented at a joint board.”

STS-134 and STS-135 Latest:

Discovery’s STS-134 mission first appeared on the manifests last year as the LON (Launch On Need) flight for STS-133, but has now become the AMS (Alpha Magnetic Spectrometer) flight.

The mission is yet to be baselined – and technically lacks funding - although the latest Senate bill gave strong indications that this mission will fly, with a planning launch date of September 16, 2010.

Atlantis will be the supporting shuttle for this mission, taking up the LON contingency role as STS-135. ET-138 will fly with Discovery, while the Hurricane Katrina damaged tank, ET-122, is being refurbished for the LON role with STS-135.

No moves have yet been made to provide a full mission role for this flight, which will likely remain the case unless there is approval for an extension of the shuttle program.

However, the inclusion of STS-134 and its subsequent LON support flight, have bought additional time on the extension decision, with new hardware not due to fly – should the manifest receive additional flights – until 2011, as opposed to after Spring 2010, which was the previous end date for the shuttle program.

MAF are already prepared for an extension, should it be called, with part builds of tanks up to ET-141 already complete and now in storage. Further tanks can be produced by refining the programming of new friction weld machinery at MAF, in the event additional ETs are required.

ATK also realigned its Flight Support Motor (FSM) schedule for the new manifest, referencing “RSRM-114 (STS-135, AMS LON) completes manufacture: Jan 2010″ in their documentation on Thursday (L2), which was also overviewed by the PRCB.

The SSP (Space Shuttle Program) also utilized last Thursday’s PRCB meeting to ensure all the supporting elements are in place for the second half of 2010, with regards to SSME testing being arranged throughout what is already a slightly extended manifest (five presentations on L2) – which currently ends in November 2010 with the LON contingency of STS-135.

NASA managers have always said they take one flight at a time, and even with major downtime for two RTFs, the program has a historical flight rate of 4.5 flight per year. However, the challenge of flying nine missions in 17 months should not be – and won’t be – underestimated.

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

No related posts.

Highlighting the ever-fluctuating nature of the Space Shuttle Program (SSP), STS-129 was originally scheduled to fly with Discovery; however, delays to the Hubble Space Telescope servicing mission forced NASA to realign its downstream flight manifest – resulting in an orbiter swap from Discovery to Atlantis.

With the change of orbiters, as well as changes to the mission’s middeck payload, flight planners are now projecting an Ascent Performance Margin of 1,101-lbs for STS-129 based on a November 12 launch.

Furthermore, the 106 page LSFR presentation – available for download on L2 - shows that Atlantis will not exceed any weight limits for the nominal abort modes available to her Flight Crew in the event of an emergency during launch.

However, Atlantis’ weight will exceed the Contingency Return weight limit set forth by the SSP.

“CONT RTRN exceeds 233,000-lbs Nominal End Of Mission limit,” notes the LSFR presentation.

This, however, does not appear to be of great concern to the SSP as there is no further mention of this issue in the LSFR presentation.

Currently targeting launch No Earlier Than November 12, 2009, the STS-129 mission will see Atlantis deliver the Express Logistics Carriers 1 & 2 (ELC-1 and ELC -2), along with SASA and MISSE (Materials on International Space Station Experiment) 7A and 7B, to the Space Station.

Additionally, the all-powerful Program Requirements Control Board (PRCB) has filed a Change Request to add RAMBO-2 (a Department of Defense payload of opportunity) to the mission. The addition of this payload is scheduled to be discussed on April 27.

Modifications for Atlantis:

As with every OPF (Orbiter Processing Facility) flow, Atlantis will undergo a series of configuration changes/upgrades during her scheduled 127 day stay in the OPF.

The first such modification scheduled for Atlantis is the redesign of the gaseous hydrogen Flow Control Valve (FCV) elbow – a modification necessary to provide additional protection for Atlantis in the event of a FCV liberation and impact event in the gaseous hydrogen lines.

“Proposed redesign of the FCV elbows involves increased wall thickness, a change in material from CRES 304L to 21-6-9 steel, and a longer elbow arm eliminating a tube section and braze joint downstream of each elbow,” notes the presentation.

The redesign will be installed in all six downstream gaseous hydrogen line locations. Further, while this safety modification will result in a marginal weight increase for Atlantis, the alteration of the FCV elbows will not require “vibration testing.” Rather, the modification will be certified for flight by analysis.

More will follow in an upcoming article based on the FCV forward plan presentation, which was reviewed by last Thursday’s PRCB, relating to missions STS-125 and beyond.

Click here for NASASpaceflight.com articles on the FCV issue since STS-126.

The second issue, first discovered during Atlantis’ flow for the STS-115 mission back in 2006, relates to an Extended Capture Latch duct clamp and cushion installation discrepancy in avionics bays one and two.

Because of limited access to the area in question, program engineers analyzed the situation back in 2006 and determined that the affected system would continue to function properly.

As a result, the SSP accepted the condition and deferred replacement of the duct clamp and cushion until Atlantis’ next Orbiter Modification Down Period (OMDP).

Since Atlantis was originally scheduled to retire after STS-125, the duct clamp and cushion issue would not need to be dealt with as Atlantis would retire before her next OMDP.

However, NASA managers later decided to retain Atlantis for service to the Shuttle program through 2010, thus giving Atlantis two additional flights and bringing this issue back to the table for discussion.

Again, since access to avionics bays one and two is limited, requiring the removal of the Tactical Air and Navigation and Microwave Scanning Beam Landing System decoder for proper access, the SSP will likely accept an additional waiver for this condition, deferring modifications until “the next time access is obtained.”

Also, additional upgrades to Atlantis will include the installation of a resized orifice to middeck avionics bay 3A, the modification of wiring for the oxygen crossover valves, a change to the external airlock ducting configuration, the removal of a recorder box from the left OMS Pod, and the addition of acreage doublers to avionics bays four, five, and six.

For the middeck avionics bay airflow reconfiguration, the ISS payload Mice Drawer System, which will be installed in middeck avionics bay 3A will not have sufficient airflow to “to accommodate rear breathing payload in the middeck avionics bay 3A,” notes the LSFR presentation.

The intended modifications (installing a bracket in the duct to allow the installation of an upgraded orifice) will increase the airflow and provide avionics cooling support for the Mice Drawer System.

In addition to this modification, Atlantis airlock fan will be configured to run from “post-insertion through de-orbit preparation.”

The LSFR notes that the Mission Operations Directorate has determined that Atlantis’ future missions will not need to benefit from the cryo savings associated with the “use of the booster fan bypass duct.”

The new duct modification will reduce the amount of crew work associated with the fan in its current configuration; nevertheless, the option to fly the booster fan bypass duct will still be available to the STS-129 crew.

On another front, the addition of acreage doublers to Avionics Bays four, five, and six is a preventative measure to reduce the risk of ground processing damage to the avionics bay doors.

The LSFR presentation notes that “Protective doublers over the entire acreage will prevent future damage and work stoppage during damage assessment and repair effort.””

Furthermore, work will also be conducted on Atlantis’ Rudder Speed Brake (RSB) inconel thermal barrier tabs.

The tabs, which are designed to prevent ascent heating from adversely affecting the RSB assembly and which are not necessary for reentry protection, have a history of coming lose during missions. The most notable example was seen during the STS-124 flight last June when one of these tabs dislodged during the standard Flight Control Surface and RCS hotfire tests the day before landing.

Improved ground inspection techniques were added for the STS-126 mission in November. However, despite these efforts, seven tabs were found to be missing when Endeavour returned to KSC.

For STS-129, the redesigned inconel thermal barrier tabs will improve the strength of the tab’s attachment to the inside of the RSB. “The redesign effort will reduce the moment arm and stress to the spot welds and will provide a secondary mechanical attachment,” notes the presentation.

Moreover, “Redesign lengthens tab to reach screw, slides tab into spring by .70” (.30” overhang), includes more spot welds and changes the spot weld from Class “C” to Class “B” (additional quality control to ensure weld conformance).”

Additionally, ground technicians will also be charged with conducting a mandatory structural inspection of Atlantis’ Wing Leading Edge (WLE) spars.

These inspections, which would normally be conducted during an OMDP or a prolonged OPF flow, are due for Atlantis by January 22, 2010. Since this date is before the final manifested mission of Atlantis – and since the last complete inspection was back in 2003 – Program managers developed three working options for this issue.

The first solution was to simply extend the time between inspections, therefore negating the necessity to conduct the intrusive inspections (which requires the removal of several RCC panels) during the 129 flow.

Nevertheless, the SSP decided that it could not accept any justification for not performing at least some of the inspection.

To this end, Atlantis’ engineers will perform WLE spar inspections of RCC panels 9-16 on each wing during the STS-129 OPF flow. The Program is expected to accept the risk of a partial inspection during a PRCB meeting April 24.

Furthermore, one final modification for Atlantis relates to her Shuttle Remote Manipulator System (SRMS) – or robot arm.

Due to a back-up release stall problem on STS-103 in December 1999 – and the fact that raybestos brakes/clutches are no longer available – the shuttle fleet’s SRMS End Effectors are being upgraded with ceramic material brakes.

Endeavour’s SRMS End Effector was upgraded last summer before her STS-126 flight; Discovery’s SRMS End Effector is being upgraded for her STS-128 mission in August.

Atlantis is scheduled to have her SRMS End Effector upgraded during the STS-129 flow; however, delivery of the new End Effector is currently two days behind the KSC need date. The presentation notes that the Government Flown Equipment team is working with the KSC team to refine the delivery dates at this time.

As always, refinements to Atlantis’ flow for STS-129 will be made over the coming weeks and months after the vehicle returns from the Hubble Telescope servicing mission.

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

No related posts.

With the unique nature of Atlantis’ STS-125 mission in prime focus for NASA managers, of particular interest – mainly the increase of orbital debris concentration at the mission’s altitude – is the region of Low Earth Orbit Atlantis will fly in for the majority of her mission.

Originally analyzed last September ahead of the original STS-125 launch date, the all-powerful Program Requirements Control Board (PRCB) has re-evaluated the threat posed to Atlantis and her seven member crew by MMOD.

The new results, which take into account recent satellite breakups and a variety of other components, show that the overall risk of a Loss Of Crew and Vehicle (LOCV) scenario due to MMOD impact(s) to the Thermal Protect System (TPS) is 1 in 185 – the exact same ratio as the original assessment back in September.

NASA analysts were able to reach this particular ratio by making use of the known probability of detecting and repairing critical TPS damage while on orbit, the “IDC of RCC panels 8-11,” the flight’s mission duration and the Orbit Adjust maneuver post-HST release, and the STS-400 rescue mission.

However, as defined by NASA guidelines, the Space Shuttle Program cannot accept a LOCV ratio in excess of 1 in 200. Since the STS-125 LOCV ratio is 1 in 185, the final decision on whether or not this ratio is acceptable will be discussed during the SOMD FRR on April 30 – at which it is anticipated that this LOCV risk will be accepted for STS-125.

On the other hand, the MMOD LOCV ratio for the STS-400 rescue flight is 1 in 294 – with late-inspection of the Wing Leading Edge (WLE) panels and Nose Cap on FD-5 and a short mission duration of seven days driving the calculations.

If the STS-400 crew does not perform any TPS inspection, the LOCV ratio rises to 1 in 217.

The PRCB presentation goes on to note that the LOCV ratios for STS-125 and STS-400 have an error factor of 1.35 based on MMOD distribution, velocity, and density uncertainties.

Additional MMOD Risk Mitigations Since October:

For the original October 2008 launch date of STS-125, NASA determined the overall MMOD risk to be 1 in 185.

In formulating this ratio, NASA determined that the now standard late-inspection of the Orbiter’s TPS would reduce the MMOD threat by 37 percent and that altering Atlantis’ orbit after the TPS late-inspection so the perigee would be 160NM would further reduce the MMOD threat by 6 percent.

Furthermore, the mission was “designed (timeline, attitudes, TPS Inspections, etc.) to minimize critical TPS exposure to MMOD while staying within the HST systems operational constraints,” notes the expansive PRCB presentation available for download on L2.

Additional elements taken into consideration were: protecting the HST’s aft shroud and Orbital Replacement Units from direct sunlight during the mission’s EVAs, maintaining a “Payload Bay to Earth” orientation as much as possible, and minimizing EVA and Orbiter MMOD exposure.

All of these assessments and mission design elements remain unchanged for the now-planned May 12 launch. However, as the presentation notes, the MMOD environment has changed since October.

“Recent satellite breakup events have increased the background Orbital Debris flux by 36 percent.”

These breakups include the Chinese ASAT/Fengyun 1C, the Kosmos 2421, and the Kosmos 2251/Iridium 33 satellite collision – all of which respectively account for 27 percent, 1 percent, and 71 percent of the total orbital debris flux increase.

These satellite breakups themselves resulted in an increase of the MMOD LOCV risk to 1 in 157 for Atlantis.

However, given the lengthy delay to STS-125, mission planners were able to investigate and baseline several new MMOD mitigation tactics.

The first change to the mission’s timeline relates to the FD-9 activities.

Instead of performing the late-inspection of Atlantis’ WLE panels and Nose Cap on FD-9 and then adjusting Atlantis’ orbit on FD-10, both activities will now be performed on FD-9.

“Moving the Orbit Adjust maneuver to FD-9 reduces the MMOD risk by an additional 3 percent,” notes the presentation.

Moreover, IDC imagery of the Atlantis’ RCC panels 8-11 will further reduce the MMOD risk by 14 percent as the lower surfaces of RCC panels 8-11 have the tightest failure criteria.

“First four passes of the starboard and port Wing Leading Edge LDRI scans will be scheduled during daylight to support parallel IDC imagery ops,” notes the PRCB presentation. “Dedicated Port IDC Scan added for critical areas not available during parallel ops.”

With these mitigations, as well as a few others which are not mentioned in the presentation, the overall MMOD LOCV risk for a May launch of STS-125 is the same as it was for October: 1 in 185.

Additional Mitigation Studies:

In addition to the already baselined MMOD mitigation tools, mission managers are continuing to assess other mitigation options.

The first alternative mentioned in the PRCB presentation is the option of delaying the TPS late-inspection by 15 hours, thereby pushing the activity into FD-10. This would result in an approximate risk reduction of 3 percent to 1 in 190.

Nevertheless, the effect this delay would have on imagery review and repair operations has not been assessed.

This, however, is the last risk reduction option that would not involve shortening the mission. The three remaining options all involve the deletion of mission content or crew off duty time.

These options include eliminating one EVA day (which would reduce risk by ~6 percent to 1 in 196), eliminating two EVA days (which would reduce risk by ~12 percent to 1 in 208), and eliminating the crew off duty day post-HST release (which would reduce risk to 1 in 201).

Whether or not any of these options are added to the mission’s timeline, work to prepare the STS-125 mission for flight is in full swing, with the STS-125 mission’s payload scheduled to be delivered to Pad-A later this week and STS-400 rescue vehicle scheduled to take her place atop Launch Pad 39-B Friday morning.

See also: Endeavour: MMOD hit to radiator
See also: Atlantis: MMOD hit originated from another vehicle
See also: MMOD hit on Endeavour window

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

Related posts:

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The Payload:

STS-132 will mark the 32nd and final “scheduled” flight of Space Shuttle Atlantis since her inaugural flight in October 1985. Targeting launch No Earlier Than (NET) May 13, 2010, STS-132 has been baselined as an 11+1+2 day mission, with three scheduled EVAs (spacewalks) and the option to add an extra EVA should the need arise.

For launch, Atlantis will use External Tank ET-136, Solid Rocket Booster set BI-143, and Reusable Solid Rocket Motor set 111. Atlantis will also fly with the OI-34 operating software.

To accomplish all of the mission’s objectives, Atlantis will carry the MRM-1, the Integrated Cargo Carrier – Vertical Light Deployable (ICC-VLD) with several assorted payloads, along with a sidewall SPA Beam payload.

Packed onto the MRM-1 will be several module-specific items as well as spare parts and a portable work platform, as outlined in the PRCB baseline presentation – available to download on L2.

Among the various items attached to the outside of the MRM-1 will be several pieces of outfitting hardware for the MRM-1′s Multi-purpose Laboratory Module (MLM). These items include the MLM payload airlock, the MLM radiator, a spare elbow assembly for the European Robotic Arm (ERA), and the Portable Work Platform for the ERA.

In addition to its externally mounted payloads, the MRM-1 will carry approximately 1,400 kilograms of internal U.S. supplies to the ISS. After MRM-1 is installed, the total usable stowage volume available to Expedition crewmembers will be 6.0 m3.

The second major payload of the mission is the ICC-VLD, a cargo carrier that will be packed with eight payload elements.

These elements include six P6 Channel 4B batteries, a Space to Ground Antenna (SGANT), a SGANT boom, the Enhanced Orbital Replacement Unit Temporary Platform (EOTP), two Power Video Grapple Fixtures (PVGFs), a Power Distribution Unit, several EVA Aids (including worksite interface fixtures and handrails), and a Fuse Box.

Furthermore, the final cargo element is the sidewall SPA Beam plus Passive FRAM. This payload will be contained within a standard Sidewall Mounted Carrier and will be delivered to the ISS during the mission.

A “to be determined” ISS ORU (Orbital Replacement Unit) payload will return to Earth with Atlantis in the Sidewall Mounted Carrier.

To support the diverse nature of the STS-132 payload, several Payload Bay (PLB) support elements will be flown – such as the Remote Operated Electrical Umbilical, which will provide power and data to the MRM-1 while it is berthed in Atlantis’ PLB.

Furthermore, an EVA Cable Stowage Hardware will be installed in PLB port bay 6. This element will support LTA cable stowage for the ICC-VLD. Additionally, several Payload Power Switching Units will be used in PLB starboard bay 5 to route power to the ICC-VLD.

Finally, a Station Power Distribution Unit will provide power to the OBSS LCS sensor during docked operations.

As always, Atlantis will fly several middeck payloads during STS-132.

During ascent, Atlantis will carry three passive lockers which will include one ambient GLACIER and one late load/time critical payload investigation, a National Lab Pathfinder (a Commercial Generic Bio-processing Apparatus), one GLACIER unit, and one International Partner allocation payload.

At the end of the mission, Atlantis will return with two powered lockers including two GLACIER units and one International Partner conditioned Unit.

As has been seen with previous flights, Atlantis will conduct several payloads of opportunity if time permits. These payloads of opportunity include MAUI, SEITE, RAMBO-2, and SIMPLEX.

Mission Objectives:

As with every flight, mission managers have identified, and categorized, the primary mission objectives for STS-132.

In order of criticality, the objectives are: activation and checkout of the MRM-1, installation of MRM-1 to the FGB Nadir port, transfer of water and critical ISS middeck cargo elements, deployment of the ICC-VLD and subsequent installation to the MT POA (followed later in the mission by the return of the ICC-VLD to Atlantis’ payload bay), removal and replacement of six P6 Channel 4B batteries, installation of SGANT to the Z1 truss, removal of the OTP and installation of the EOTP on the SPDM, and completion of middeck cargo transfers to and from ISS.

Most of these mission objectives will be accomplished during the mission’s three EVAs.

SGANT and boom installation to Z1 will occur during EVA-1 on Flight Day 4 (FD-4) with ICC-VLD installation on POA following shortly after the completion of the EVA.

For EVA-2 on FD-6, four P6 batteries will be Removed and Replaced and the Space Station Remote Manipulator System (SSRMS) will remove the ICC-VLD from the POA.

During EVA-3, the final two P6 batteries will be R&Red, the ICC-VLD will be reinstalled on POA, and the OTP will be removed and the EOTP installed to the SPDM.

Unberthing of MRM-1 from Atlantis and installation on FGB Nadir will occur on FD-5 (though ingress to MRM-1 is not currently planned under the initial mission timeline) and reberthing of the ICC-VLD into Atlantis’ payload bay will occur on FD-9.

Under the preliminary mission timeline, Atlantis will undock for the final time from the ISS on FD-10 for a landing on FD-12.

However, despite initial planning efforts, early indications are that the EVA content of the mission will not fit within the allotted three EVA structure. Robotic choreography and “EOTP removal from ICC and R&R with the OTP doesn’t fit in preliminary timeline,” notes the baseline document.

In addition to these timeline issues, flight planners are also evaluating the positioning of the PVGF on the ICC-VLD, conducting robotics analyses of the cargo element transfer operations from the ICC-VLD using the SSRMS, and examining EVA crew access, clearance, and task time assessments for the SGANT and SGANT Boom transfer operations.

Further assessments for the mission include information on the projected launch weights for MRM-1 and ICC-VLD and the vehicle’s overall Ascent Performance Margin. For STS-132, the projected APM is 1,576lbs with the projected weight of MRM-1 coming in at 17,417lbs and the weight of ICC-VLD coming in at 7,790lbs.

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

No related posts.

STS-127/400 Processing Latest:

Endeavour is on track to rollover from her Orbiter Processing Facility (OPF-2) on Friday morning, before rolling out to Pad 39B as part of the STS-400 LON (Launch On Need) requirement.

“Final roll preps and forward and aft compartment closeouts continue. Rollover to the VAB (Vehicle Assembly Building) is scheduled for Friday morning,” noted Monday processing information on L2.

“Preps for landing gear functional are complete. Landing gear rigging checks, NLG (Nose Landing Gear) strut pressurization, and landing gear door thermal barrier rework were all worked over the weekend. Landing gear functional is scheduled for today.

“Mid/Aft structural leak test and positive pressure test were completed on Friday. Final tire pressurization for flight is scheduled for tonight.”

Following the stand-down of STS-400 requirements – via the clearance of Atlantis TPS (Thermal Protection System) during the latter part of STS-125 – Endeavour will be prepared to roll to Pad 39A, ahead of her primary STS-127 mission, which is tracking a June 13 launch date.

STS-127 Payload: 

The STS-127/2J/A mission package includes the Japanese Experiment Module – Exposed Facility (JEM-EF) and the Japanese Experiment Logistics Module – Exposed Section (ELM-ES) as well as the Integrated Cargo Carrier – Vertical Light Deployable (ICC-VLD).

Attached to the ICC-VLD will be six P6 truss batteries (which will be part of the P6 battery R&R activities during one of the mission’s EVAs), a Linear Drive Unit, Pump Module #2, and a Space to Ground Antennae – all of which will be transferred to ESP-3 (External Stowage Platform-3) during an EVA.

In addition to these primary payloads, Endeavour will fly with DRAGONSAT (Dual RF Autonomous GPS On-Orbit Navigator Satellite), the MAUI (Maui Analysis of Upper-Atmospheric Injections), ANDE-2 (Atmospheric Neutral Density Experiment-2), SEITE (Shuttle Engine Ion Turbulence Experiment), and SIMPLEX (Shuttle Ionospheric Modification with Pulsed Local Exhaust).

STS-127 Mission Duration Extension:

Due to the packed nature of the mission, managers discussed potential solutions to the SCSC rule breach, relating to off duty time for the crew.

“Issue: The 15+1+2 Mission Duration does not allow enough time to accomplish the specified ISSP/SSP mission objectives and complete the required Crew Off Duty without an SCSC Violation,” noted the outline in an expansive PRCB presentation, available on L2.

“Specifically, we were unable to meet SCSC 2.6.1.3.a which states: The off-duty time is not scheduled on a daily basis but is scheduled in a block(s) of 4 hours’ duration. Any off-duty time remaining after the 4 hour block(s) has been scheduled must be scheduled as a continuous off-duty block of time.”

The issue had been known for some time, with several meetings utilized in an attempt to find get-wells in the flight plan. However, those evaluations failed to find a solution that worked with the previous mission timeline.

“The Flight Plan was reviewed at several STS-127/2JA meetings including reviewing the: Order hardware is removed from the PLB (Payload Bay). EVA and Robotics flight day placement. Specific Robotics choreography. Estimated times for specific activities such as JAXA payloads.

“The team was unable to determine a solution that accomplishes all mission objectives and the required Crew Off-Duty in a 15 day mission.”

This left managers with two options; increase STS-127 to a 16 day mission, or remain at 15 days while reducing mission content – specifically the deletion of EVA 5.

“15 Day Option: Maintain the 15+1+2 mission and reduce mission content. The recommended reduction is the deletion of EVA 5. Deletion of EVA 5 maintains all other mission objectives with a 15 day mission and eliminates the SCSC violation,” added the presentation. “Currently, all tasks on EVA 5 are deferrable from STS-127.

“The JAXA MLI task is only deferrable until HTV. Additional EVA tasks based on 15A results are under consideration for STS-127 by the ISSP.

“Currently E19/20 does not have a stage EVA planned between 2JA and 17A. A quick assessment by the lead FD indicates time is available if the ISSP added this requirement. Other solutions are more complicated and involve leaving hardware such as the ICC-VLD or JLE on orbit.

“Off-duty required for 15+1+2 mission is 9.00 hrs: 3.25 hrs of off duty would be placed on FD7. 5.75 hrs of off duty would be placed on FD11.”

The option of moving to 16 days allows for the crew to use parts of Flight Day 7 and mainly Flight Day 11 for off duty time, whilst keeping all mission content in place.

“Increase mission duration to 16+0+2: This timeline meets ISSP/SSP mission requirements including: SCSC Crew Off-Duty Requirements. 5 EVAs (5 EVA Days, 6 Non-EVA Days between dock & undock),” added the presentation.

“Return of the ICC-VLD and the JLE. Off-duty required for 16+0+2 mission is 9.75 hrs. 3.25 hrs of off duty would be placed on FD7. 6.5 hrs of off duty would be placed on FD11.

“For STS-127/2JA FOR the off duty day was placed on FD13 to accommodate the Soyuz docking. With the launch date move to June, the Soyuz is no longer a mission objective. The STS-127/2JA team is updating the timeline and placing the crew day off on FD11.”

The decision to move to 16 days allows for all mission content to be completed on a nominal timeline. The STS-127 crew have been informed of the PRCB decision.

“Increase the STS-127/2JA mission to a mission duration of 16+0+2,” noted the recommendation. “This has been coordinated at the STS-127/2JA JOP, the 2JA ISSP IPT, the STS-127 SSP IPT, and with the STS-127 crew.

“With a mission duration of 16+0+2 the EVA content will be 5+0. If a contingency EVA is required, EVA 5 will be deleted and used for the contingency at the required time during the mission.

“This option maximizes mission content return for the ISS program, any additional changes or mission contingencies will require a reduction in objectives. Special attention needs to be placed on mission priority development and documentation in this case.”

Options exist should managers decide to revert back to a 15 day mission, based on the latest MMOD risk numbers.

“The PRCB decided to hold the full CR (Change Request) decision until the MMOD risk numbers are available to compare the risk for a 15 day mission versus 16 day mission,” added Monday’s 8th Floor News on L2. 

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

No related posts.

The presentations presented to the PRCB (all available on L2) concentrated on associated risk assessments, a key hurdle to overcome to achieve the required flight rationale for a NET (No Earlier Than) March 11 launch date.

At present, confidence is high that the three replacement valves - now installed into Discovery - are free of any cracks, thanks to recent “eddy current screening” testing, which has proved capable of finding small cracks that can form on the valves’ poppets.

In turn, this mitigates the risk of a failure that could threaten an over-pressure of the tank, which would result in the ET venting – a fire hazard during early first stage flight - or under-pressure of the tank, which risks the orbiter’s SSMEs (Space Shuttle Main Engines) shutting down.

Systems Engineering and Integration Office (SE&I), one of the main bodies tasked with approving flight rationale, overviewed the main risks that are threatened by such scenarios.

“Risk due to Over-pressure/Under-pressure: ET LH2 tank over-pressure from increased flow is protected by relief valve. ET Intertank over-pressure not credible based on venting capability,” noted one of their presentations from Wednesday’s Special PRCB.

The comment of the event not being credible is based on the assessment that such an event is “Infrequent” on the risk matrix, which is very small for what is flight rationale for just one launch.

“Risk due to Flammability of GH2 leak (Classified as Infrequent Catastrophic due to Uncertainty),” added the presentation. “Risk from flammability present from engine start to T+120 sec. GH2 venting through ET vent valve risk due to FCV poppet failure (1:41000-5th, 1:4500, 1:1400-95th).”

Following positive news on ability to gauge how much of the FCV’s poppet diameter is at risk of liberating during a failure, SE&I were also able to class an under-pressure scenario as “non credible”.

Click here for NASASpaceflight.com articles on the FCV issue since STS-126.

It has been evaluated that it would take two valves to liberate pieces greater than a diameter of 125 degrees within the first 60 seconds of flight to cause venting. An under-pressure scenario would be caused by the liberation from the valve punching a hole in the 90 elbow immediately downstream of the FCVs.

“ET LH2 tank under-pressure is a non credible scenario based on size of FCV particle relative to size of hole required for under-pressure condition,” added SE&I. “Orbiter aft compartment overpressure not credible for size of FCV particle and the hole size required to create delta pressure that exceeds certification.”

Ending on a positive note, “SE&I Recommends proceeding to Launch of STS-119 based on Orbiter Project mitigations with hardware inspections and acceptable risk of the effects.”

The Orbiter Project, which has been involved with the FCV issue since it was observed during STS-126′s ascent, also gave a positive overtone on the status via their 85 page presentation to the PRCB.

“FCV poppets installed in OV-103 (Discovery) are crack-free to limit of NDE (Non Destructive Evaluation) detection capability. Cracks at NDE detection limit require multiple flights to grow to failure.

“Fractography and analysis indicate that cracks require some number of flights to grow in high-cycle fatigue plus additional time in a static loading environment. Bounding analysis predicts a max particle size of 125 degrees.

“Venting analysis shows no ET venting for 160 degree poppet liberated at T-0. ET Venting prior to 120 seconds requires two 125 degree poppet failures in the first 60 seconds. ET under press requires a leak size much larger than demonstrated in impact testing

“Monte Carlo analysis of particle impact consequences shows a low risk of damage causing leakage. Risk of orbiter aft over pressurization requires a significant line rupture and is unlikely.”

Only one item appears to be outstanding, approval for the installation of the doubler plate, which would be used to add protection to the 90 degree elbow, should a liberation from the valve occur during the ride uphill.

“The use of the doubler assemblies are assessed in four categories: 1) Capability to contain poppet fragment from entering the aft compartment. 2) Capability to prevent or minimize a GH2 leak into the aft compartment. 3) No adverse affect to the MPS GH2 manifold. 4) Maintain structural integrity,” outlined the Orbiter Project.

“A 0.25 gram poppet fragment impacting the elbow inner wall at a knife edge orientation, 90 degrees at 850 fps punctures a hole in through the elbow wall.

“The doubler assembly successfully prevented a 0.25 gram fragment knife edge orientation, 90 degrees at 1025 fps from breaching the MPS (Main Propulsion System) system. The particle pierced the elbow wall but contained within the system by the doubler assembly.”

However, despite the doubler’s ability to add protection to the elbow, more data is required on the loads assessment, which is being carried out by Boeing at Huntington Beach. This testing is believed to be taking place on Wednesday evening, with a schedule to approve and begin installation into Discovery’s MPS this week, should the results prove to be favorable.

“Orbiter Project Elbow Reinforcement Recommendation: Pending Resolution of Boeing Huntington Beach loads assessment and other concerns expressed with fracture criticality etc, all OPO members were GO to fly doubler. (Numerous departments) require vibration testing prior to flight. (Several Departments) do not require vibration testing.”

Interestingly, with the latest data showing that it would likely take a double valve failure – over the expected margins of liberation from the FCV poppet - the threat of a breach causing an under-pressure scenario in the External Tank are low enough to potentially fly without the doubler. This is likely to be the focus of attention over the next few days.

“OPO (Orbiter Project Office) Recommendation: Acceptable to fly doubler on STS-119 mission but not required for flight.Poppet liberation risk low based on eddy current inspection. Must resolve certification loads issue before installation.”

The positive news from the PRCB has come at the end of a long process, that ultimately is only likely to delay STS-119 by a total of one month, a major achievement that earned praise from shuttle manager John Shannon.

“The team needs to be proud. After finding additional cracks in the 1301 poppets, it developed the eddy current screening technique and did a great deal of work on the Monte Carlo modeling to combat this problem,” noted Mr Shannon to the teams. It is an amazing job.

“By performing this work, the team has preserved the option to launch in this period – a critical issue to NASA. I cannot tell you how proud I am of the team. It has been a great effort.”

L2 members: Documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size.

Related posts:

1. ISS prepares for arrival of STS-126 – STS-119 launch date advancement debate With STS-126 closing in on the start of S0007 –...