Realigning the shuttle surge – full review of the orbiter flows

by Chris Bergin

As the fleet awaits news on how the External Tank deliveries will shape the upcoming manifest changes, all three orbiters won’t add to that equation, as OPF (Orbiter Processing Flows) continue smoothly.

With Endeavour now back inside her home OPF, engineers have begun to check her systems, with the opening reports pointing to a clean orbiter – following her record breaking STS-123 mission.

**The most comprehensive collection of Shuttle, Ares, Orion and ISS related presentations and mission documentation, plus expansive daily processing documentation and updates are available to download on L2 **

**Click here for sample of L2 menu and content**

**STS-123 Special: MOD Flight Readiness Review (FRR) Presentations, Baselines and Mission Overviews. 

Over 35 Checklists and Handbooks, plus STS-123 Flight Plan and Detailed Mission Timeline Overviews. LIVE MMT Level Flight Day coverage (Memos, Info, Images, Videos and Presentations).

**STS-123 L2 Special: 2,500mb in size – now heading into Post Flight MMT level coverage.
STS-124 Sub Section Build-Up.
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 **LIVE news updates on Endeavour STS-123 POST FLIGHT**

**LIVE updates on Atlantis STS-125 Processing Flow**

**LIVE updates on Discovery STS-124 Processing**

Post STS-123:

Endeavour arrived back into her ‘barn’ at 1:15am Thursday morning, before being spotted and mated with the T-0 umbilical, ahead of being jacked off her wheels and levelled.

Minor damage has been noted – most of which is likely to have been suffered during touchdown and rollout at the Shuttle Landing Facility (SLF) – though overall the vehicle is reported to be in good shape.

‘Runway report is circulating via email and the vehicle overall looks good,’ added the latest Shuttle Stand-up/Integration report. ‘Have gaps on chin panel that might require it to come down.

‘No evidence of cracking on window 1 from access they had. Have frayed thermal barriers, protruding gap fillers, minor tile damage, and one notable BRI tile on nose landing gear door that was chipped off. Looks normal overall, and have nothing to be concerned about.’

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A few issues or IPRs (Interim Problem Reports) have been listed already, though nothing more than sticky switches on the crew cabin panels and with the T-0 umbilical connections, though one note of interest refers to the UHF radio, which was causing some issues pre-launch.

‘Random tones heard on audio system (GTOE headset). The tones were determined to be on the UHF ATC radio. Ground troubleshooting detected RF noise in OPF Bay 2 near the frequency of the UHF radio,’ added processing information.

‘The RF noise at first appeared to be associated with the Portable Purge Unit (PPU) but between 1117 and 1158 EST the noise fluctuations stopped with no corresponding change to the PPU operation. Further troubleshooting is required to isolate the RF noise source.’

Endeavour’s payload bay doors will be opened on Saturday, which will allow for the removal of the T-RAD DTO package – a demonstration package of samples that will hopefully certify the tile repair technique for future flights.

Shuttle manager John Shannon spoke on the Stand-Up of his eagerness to get the package out of KSC for testing at JSC’s Arc Jet Facility. It was also noted that the completion of this task on STS-123 allows for an additional payload to be added to Discovery’s STS-124 middeck payload. 

Engineers also confirmed there was no issue with Endeavour’s APU 1 (Auxiliary Power Unit) – after a pressure decay was noticed on orbit. A root cause for the N2 leak will now be evaluated.

‘STS-123 APU-1 fuel tank pressure decay: All toxic vapor leak checks have been zero parts per million. Ground Ops team and PRT put together good trouble shooting plan to determine cause of leak, whether it’s the QD (Quick Disconnect) cap or not. N2 leak is benign.’

STS-126 (LON-400):

Endeavour is currently undergoing what is classed as Integrated Roll In Operations, ahead of starting her processing towards what will be multi-role requirements.

Her processing will target an opening requirement to be the LON (Launch On Need) orbiter in support of Discovery’s STS-124. Given the reported issues with the downstream External Tank (ET) delivery dates, the target Endeavour would need to be ready to roll to the VAB (Vehicle Assembly Building) is fluid at present.

Once Discovery arrives back home safely, Endeavour will be switched to the unique (STS) LON-400 role – which will see her rolled out to Launch Pad 39B, ahead of Atlantis’ launch to the Hubble Space Telescope. There she will remain until the LON requirement is stood down, and Pad 39A has been processed to accept Endeavour.

Rather than rolling back to the VAB, Endeavour and her stack will rollback off 39B, head to the folk in the crawlerway, and then roll forward to the vacated 39A ahead of STS-126 – itself a highly interesting mission.

STS-126 will be the heaviest logistics flight ever, carrying supplies, including a new six-crew Galley, to the International Space Station, while also carrying out a unique re-entry experiment – a Boundary Layer Transition (BLT) Detailed Test Objective (DTO).


With Discovery’s processing currently green, Monday will see NASA officially announce May 31 as the new NET date for the mission.

ET-128 is now in the VAB, ready for mating with the SRBs, following a stagnated trip from the Michoud Assembly Facility (MAF) in New Orleans. A delay to the ET lift in the VAB only proved to be an overnight delay.

“Mr. Shannon appreciated the entire team that delivered the tank to KSC,” added the Stand-up. “They were challenged by the weather on the trip down. They did a great job and showed good judgment in how they executed this.”

Discovery herself will have a bit of a wait before she can rollover to the VAB to be mated with the rest of the stack, as she comes to the end of pre-launch processing inside her OPF. Currently April 13 is set for ET mate, with April 28 for mating Discovery with the stack.

“On vehicle in OPF, TPS processing is going well; only have 7 cavities left. Rollout inspection is 90 percent complete. Payload bay doors closed for rollover (Friday),” added processing information..

“Aft closeouts have begun and continue through next week. Final payload bay cleaning and aft bulkhead debris cover installation is complete. Final payload bay door closure along with final Ku-band stowage. Midbody and aft structural leak tests after payload bay doors are closed. ET doors will be closed as needed to support this leak test.”

No constraint for rollout is an issue with Pad 39A, which is noted to have suffered some erosion below the pad surface. Mitigation efforts are being put into place for STS-124. This is usual after a launch, with repair work a norm for post launch pad requirements.

“At the pad, have reports there was erosion below the pad surface. Have automatic wash down system in place for zinc abatement, which has caused water to flow into different areas.

“Found underneath pad surface, a cubic yard of sand that has eroded out underneath. Have plan in place to put concrete in that area and backfill it. That will take care of this mission; it is not an issue for this mission or schedule.

“For upcoming launch, will position orbiter transfer vehicle (OTV) cameras so can determine water flow, and for next launch put a diversion in place to prevent the erosion.”


Atlantis’ flagship mission to service the Hubble Space Telescope is currently awaiting the manifest realignment, likely to result in a new October target for STS-125. It is not known if any announcement will be made in the short term, with MAF meetings still on-going through next week.

Processing on Atlantis is proceeding on the timeline, with a large amount of work and modifications being carried out on the orbiter.

“Aft vernier thruster (R5D) removal and replacement began Thursday and continued through Friday,” noted the latest processing information. “MCA3 cold plate repairs were worked Thursday and continued through Friday. FES (Flash Evaporator System) core leak checks were successfully completed. FES system functional checks pick up Friday.”

For the interim, engineers are completing work on Atlantis’ Thermal Protection System (TPS) and notably her RCC (Reinforced Carbon Carbon) panels, which gained additional attention due to a “spalling” concern – a concern that has diminished greatly since according to separate documentation – along with a changeout of a failed thruster.

“Have 116 cavities, which is average for a flow. On WLE (Wing Leading Edge), have panel 16L and 17L going up for flight today. Next week, 17R is going up for flight. For 17R, have root cause team coming down to watch installation. Panels 14L and 10R are still under engineering evaluation on whether or not they need to be changed out.

“Engineering has looked at the L/H air data probe which stalled out under one motor condition. Have special torque test scheduled on April 1. Have pass/fail criteria lined up for this. Will run the torque test, and either accept it as is or change it out. Are on schedule.

“R5D thruster will be R&R’d as result of in-flight heater failure. SCAPE operation and drain system (Friday). On Friday next week, will do another SCAPE operation and R&R the thruster.”

An issue during the latter stages of the STS-122’s countdown was an Omega bend/kink in her starboard aft radiator retract flex hose. This required a special pole being used at the pad to aid the successful retraction.

Evaluations on a forward plan are still being worked – notably because the hose did once again kink during payload bay door closure on orbit ahead of the deorbit burn. No leak, however, was noticed by controllers on the ground – and a mitigation procedure was already in place had that occurred.

Testing continues at Huntington Beach in California, which has noted the “radiator retract hose had excessive torque during cycling. Engineers met on this, looked at data, and determined to accept hose as is. Will finish testing and will meet delivery date for changeout on OV-104 (Atlantis).”

Meanwhile, SRB build up for STS-125 has already begun, exemplifying how well the KSC workforce is coping with the surge in projected launches – even if that has been slightly derailed by the ET delivery delays.

ET Processing Latest:

STS-125 requires set timelines for the arrival and processing of both ET-127 – the primary tank to fly with Atlantis, and ET-129 – which will sit with Endeavour during LON standby, for a solid launch date. These dates are still under review.

MAF met this week to discuss possible ways of catching up some of the lost timeline at a TIM (Technical Interchange Meeting), which a hint at a request for some additional cash to allow additional hours to be spent on the tanks – likely in the hope of protecting against any future delays.

“Had a TIM Wednesday with Lockheed Martin (who are the contractor at MAF),” noted the Space Shuttle Program (SSP). “Discussed enhanced productivity and compressed schedule. Presented budget exercise to Level II yesterday.”

From long term schedules, it appears tanks downstream of ET-129 do not have the same issues – with processing timelines classed as green. This adds confidence that MAF – who have performed nothing short of minor miracles with getting tanks out of the door since being struck by Hurricane Katrina – may only need to focus on ET-127 and ET-129 for manifest protection.

Current state of play with those two tanks shows just how much work is taking place.

“ET-127: Down to three ice/frost ramp bases left to complete. They’re all sprayed and trimmed. A couple are ready for presentation to quality; on others they’re working a few repairs. This will finish up all base activities. Many lower frost ramps are going down on ice/frost ramp,” reported MAF to the SSP at the end of this week.

“Sprayed longeron A&C pockets (both +/- Y side). Looking at modified closeout approach to get in time to put on ET-129. Bi-pod heater plates and bi-pod fittings and cells are installed. Moving towards preps for closeout spray on bi-pod; want to do harness routing first.

“Continue to do routing inside intertank. Working electrical and tubing installation on ogive towards nose cone. Are beginning work on back end of tank such as thrust strut flange closeout sprays.”

“ET-129: Continue to set up intertank scaffolding inside. Working preps to do LO2 feedline base sprays. On LH2 tank, looking at approaches to mitigate impact of new design on production. Have all fourteen LH2 window cutouts in work. Nine are completely trimmed, and other five are currently in trims. Moving towards base sprays quickly. Also, moving to get tolerance relief and some trim tools to help.”

Notes of interest on future missions:

STS-119, which will carry up the final power generating array (S6) for the ISS, is likely to slip into 2009, should the expected delays be incurred by STS-125 and STS-126. However, information points to an interesting requirement being looked at, should Discovery’s flight – currently manifested for December – be required to return home before offloading the payload.

“STS-119 is performance critical (S6 truss). Team determined that for contingency payload return, they were able to implement multi-stage de-orbit and gain 500 pounds of mass in the middeck, which helps Station.”

A future flight will also gain a special test (DTO) for Constellation, one of what could be many, as SSP continue working on a process for joint Shuttle, Station and Constellation DTO requirement approvals.

“Met with Constellation Program this week,” noted JSC’s Orbiter Project, “who have a relative navigation DTO they’d like to fly on Shuttle in early 2010. Assigned manager from Orbiter to head this up, integrate it into the Orbiter and help Constellation make the DTO successful.”

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