STS-124 payload awaits Discovery at Pad 39A – Fleet update
The huge Japanese Pressurized Module (JPM) has been transferred to Launch Pad 39A, ahead of Saturday’s rollout of shuttle Discovery – as STS-124 preparations enter the final stretch ahead of May 31’s launch date.
Meanwhile, evaluations are continuing on the next two External Tanks (ET-127 and ET-129) – which are still undergoing production at the Michoud Assembly Facility (MAF) – as shuttle managers debate as to when they will be able to launch the final servicing mission to Hubble.
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**STS-124 Sub Section Build-Up – special section Now Live.
**STS-125/LON-400 Sub Section Special already over 1300mb in size – special section Now Live.
**LIVE updates: Endeavour Dual LON and STS-126 Processing**
**LIVE updates on Atlantis STS-125 Processing Flow**
**LIVE updates on Discovery STS-124 Processing (VAB FLOW)**
Discovery rolled over to the Vehicle Assembly Building (VAB) on Saturday morning, before being hard mated with ET-128 the following afternoon. As of Wednesday morning, S0004 (Orbiter/ET mate) operations are continuing on the timeline to make Saturday’s rollout.
‘LO2/LH2 monoball connections were completed yesterday. Shuttle Interface Test (S0008) is in work,’ noted Wednesday processing information. ‘Call to stations was completed at 2047 EDT last night. The vehicle was powered up early at 2200 last night.
‘(Shuttle manager) Mr. (John) Shannon congratulated the GO team for their work on the STS-124 flow.’
As has been seen on previous VAB flows with the stack, an electrical issue with one of the booster’s data recorders was noted last night, but was soon resolved by engineers.
‘During the SRB camera functional test last night, picked up IPR (Interim Problem Report) for the RH SRB (Right Hand Solid Rocket Booster) recorder 1 not receiving an expected signal. Troubleshooting verified test setup, and reperformed test successfully.’
As previously noted, engineers are continuing to look at available options open to them, should one of Discovery’s radiator retract hoses prove to be troublesome during payload bay door closure at the pad – not due for around three weeks.
While a plan is being put into place for any hoses that bend – and thus do not retract into their boxes properly – a root cause investigation is also due for discussion.
‘Technical team is meeting in Huntington Beach this week to discuss the radiator retract flex hose buckling. Will talk potential root causes,’ noted the latest Shuttle Stand-up/Integration report.
‘Additionally will talk about what analysis and test would be required to provide confidence to fly the hose if it buckled just prior to door closure, and they could not get access to help it into the box.’
Orbiter’s have four hoses – each carrying coolant fluid Freon to the orbiter’s radiators on orbit – with the issues on recent flows relating to the two hoses in the aft of the vehicle.
It could prove to be problematic if one of the other two hoses – located at the top end of the payload bay – bend during payload bay door closure, due to the issues with accessing them, likely via the device that was used to guide the hose back into its box ahead of STS-122.
STS-122: Hose related news content (all exclusives): *Issue found/fleet to be checked (December)* – *Atlantis found to have problem* – *Managers discuss forward plan* – *Use of pole to aid retract* – *Successful Retraction*
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Discovery also has a new ET Flash Unit being installed while she’s in the VAB. The flash is used aid photography – gained from the ET umbilical camera – of the tank as it is separated from the vehicle after MECO (Main Engine Cut Off). The imagery is one of the method of checking for areas of foam loss on the tank.
‘Regarding the ET flash that was shipped down last week, it’s in Florida and are installing it in the vehicle. Did a pressure check when received, with good pressure in the flash. No concerns with the unit that will go on STS-124.’
No major issues are being worked ahead of the Flight Readiness Reviews that kick off in the next few weeks, as Discovery continues to look good for May 31.
“The STS-124 Bench Review went well; no major issues,” noted Flight Ops and Integration. “There were five squawks and 15 requests, of which theyâ€™ve closed several already.”
Atlantis/STS-125 and External Tanks:
Atlantis continues to be processed through the business end of her flow, with her Thermal Protection System (TPS) being refurbished, following her exploits during STS-122.
“Midbody reconfiguration is 90 percent complete. There is a lot of testing and closeout work that needs to happen,” noted the Stand-up. “For TPS, there are 101 cavities with 68 bonded to date. Gives us 170 cavities which is what we planned for. Thermal Protection System waterproofing completed Sunday as scheduled.”
Atlantis will be carrying out her debut mission to service Hubble, which includes an elaborate array of payload bay equipment. Testing ahead of installing those payload elements is taking place Wednesday.
“Payload premate testing is scheduled to pick up today. Hydraulic operations tomorrow to position the bodyflap, NLG (Nose Landing Gear), and elevons to support TPS operations,” added Wednesday processing information.
“PRSD (Power Reactant Storage and Distributation) system testing resumes today. Water spray boiler checkout and deservicing continues. Wing leading edge (WLE) instrumentation installation/firmware upgrade continues.”
However, just when Atlantis will launch is still under evaluation. The issue relates entirely on the delivery dates of the next two tanks out of MAF, with both ET-125 and ET-127 required at the Kennedy Space Center on a processing timeline that will determine the guideline for the launch date target.
Currently, MAF information points to a “best case” scenario of an early October launch for Atlantis, based on the delivery dates – which are still in flux – for ET-127 and ET-129, the latter required for Endeavour as the LON (Launch On Need) rescue shuttle that has to be sat on Launch Pad 39B at the same time Atlantis launches from 39A.
“ET-127 (STS-125): Have LOX extension sprays to do. Antenna installation is 98 percent complete. Intertank routing and wiring harness is in work. Externally, have machining and venting in progress,” noted MAF’s latest processing information this week.
“For the bipod, the spindle pour is in work. Have three upper IFRs (Ice Frost Ramps) being repaired due to under-pours. The LOX feedline straight section installation is in progress.”
“ET-129 (LON-400/STS-126): Have work primarily on the aft crossbeam installation and IFRs. Have four pours for IFRs in work. Have LOX mast installation in work now.”
As per normal for the MAF workforce, ‘get wells’ on the flow continue to be achieved, raising hopes that the “best case” delivery scenario may be able to move slightly to the left by a number of days. However, they are under no pressure to “rush” the schedule.
STS-126 – Endeavour’s primary mission – will launch one month after STS-125, involving a mini-rollback from pad 39B, before being placed on the vacated 39A. Based on the “best case” ET delivery dates, this mission is targeting November, which the orbiter herself is easily within the flow timeline.
“For TPS, have 52 cavities and only 1 bonded. Expect those numbers to grow quite a bit. There are 326 repairs,” noted the Stand-up, referencing TPS work following STS-123.
A final check of the remaining debris inside Endeavour’s purge circuit ducting – caused by a HEPA (High Efficiency Particulate Air) filter contamination event ahead of STS-123 – is also taking place.
“Still boroscoping for (Foreign Objects) in the system as a result of the HEPA filter problem that we had last flow,” added the Stand-up. “A few things were found, but nothing major. Will continue to do this until we feel comfortable that the system is clean.”
A waiver was issued ahead of STS-123, after engineers evaluated that none of the remaining debris observed inside Endeavour would prove to be a problem on orbit. New practises have also been put into place to avoid a similar event with the OPF (Orbiter Processing Facility) filters.
Other elements of Endeavour’s flow are proceeding as scheduled, with new brakes installed on the orbiter’s landing gear, and the replacement of some of her windows – among other flow requirements, as noted in Wednesday processing information.
“MLG (Main Landing Gear) brakes installed. Plan on getting the boom installed this week. Working on Window 6 R&R (Installation next Wednesday). Currently, only two windows need to be replaced, Windows 1 and 6. OMS (Orbital Maneuvering System) ball valve leak checks were completed last night. Flight cap installation scheduled today.”
The OBSS (Orbiter Boom Sensor System) installation, as noted above, will begin on Thursday, to be completed next week, with a spot of engineering work required in-between.
That work is required on a cracked washer. While that is not the most newsworthy engineering note ever published on this site, when placed into context, this engineering note shows just how every single inch, of what is the most complex machine ever invented, is checked during a processing flow.
“MEQ (Mechanical Systems) picked up PR (Problem Report) on a cracked ready-to-latch arm bushing cap/washer on the starboard aft manipulator positioning mechanism. Plan is to install the OBSS tomorrow (Thursday) to support rigging, then R&R the part. R&R is constraint to final OBSS installation for flight next week.”
Other work ongoing involves the MPS (Main Propulsion System) high pressure decay test, which was completed yesterday, to be followed by “12-hour decay checks, check valve and pressure disconnect validations, picked up today.”
“Antenna 3 and 5 were installed yesterday, less connector routing, clamping, and connector mates. Hydraulic operations today to support desilting, channel tests, and leak checks and to position aerosurfaces for TPS operations.
“TPS waterproofing in the bodyflap/main landing gear shadow area is scheduled for 3rd shift tonight (requires bay clear). External Tank doors were closed and latched yesterday to support BRI (Boeing Rigid Insulation) tile work.”
Vacuum Chamber Update:
Meanwhile, at the Johnson Space Center (JSC), engineers are still checking into what caused the vacuum chamber leak inside Building 7, which terminated a spacesuit test run.
“On Building 7 facility, they are still looking into the chamber,” noted JSC’s EVA department. “The EMU (Extravehicular Mobility Unit) that was in chamber 3013 was dried out and returned to Building 7.”
This, however, has not halted further test runs required for future flights, notably training for the complex rescue mission (LON-400), should Atlantis suffer a serious problem during the flight.
“Will be doing an 8-foot chamber test with that unit in support of STS-125/HST, doing the empty suit transfer for LON (Launch On Need). This will roll into an updated certification.”