Atlantis rollover waits on ET/SRB ops – Fleet processing update

by Chris Bergin

An engineering evaluation into a washer relating to External Tank (ET-127) Solid Rocket Booster (SRB) mating is the only issue being worked in the STS-125 flow, which has currently impacted Atlantis’ rollover date by two days.

While those two days may be caught up before the August 18 rollover target, STS-125 has eight days of flexibility in its pad flow – as processing continues to add confidence for the approval of the launch date advancement on Thursday.

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Atlantis/STS-125 Latest:

Atlantis is ahead of the processing milestones, as she awaits the green light for rollover to the Vehicle Assembly Building (VAB) for mating operations with the stack.

Two minor issues that have been worked inside OPF-1 (Orbiter Processing Facility) have now been cleared – namely with troubleshooting with the orbiter’s UHF Radio and a re-test of the Master Timing Unit (MTU).

Other work has involved the completion of TPS (Thermal Protection System) work, which relates to a gap filler around the Air Data Probe that is requiring repair this weekend.

‘Completed troubleshooting on UHF radio; will fly it as is,’ noted Ground Operations. ‘Completed re-test on MTU that was installed earlier this week (with nominal results). Still working a couple of TPS issues: gap filler around air data probe – repairs are in work (this weekend).’

‘Had some slight outages in the radio when thermal profile was ramped up,’ added notes on the UHF radio. ‘Radios are older hardware and have carbon resistors and carbon transistors which are sensitive to rapid changes in temperature. Determined they are all acceptable for flight.

‘Entire community including MOD and Crew Office is comfortable with flying radio as is. Will have more opportunity to test at the pad. Environments are different at the pad, so will test squelch there.

‘(Shuttle manager John) Shannon appreciated all the hard work and thanked the entire team for their hard work on preparing OV-104 in time.’

Following the successful troubleshooting, Atlantis has now powered down for the final time ahead of rollover. Final operations included the crew module closeout and final side hatch closure.

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August 18 is currently scheduled as the date for rollover. However, ET/SRB operations in the VAB are currently two days down on the schedule, via a problem centered around the now-completed mate between the tank and the twin SRBs.

The issue normally wouldn’t warrant reporting, had it not been a good example of the need for absolute perfection with every element of flight hardware – in this case, a spec requirement for less than a 0.005” gap around the circumference of a spherical washer on the Forward Sep Bolt between the right booster and the ET.

Mold impressions were taken of what appears to be a tiny bend on the circumference of the spherical washer, which is being evaluated by NASA and the tank’s contractor, Lockheed Martin – who will provide the forward plan of replacement work or flight rationale. This is, however, a minor issue in the grand scheme of operations.

Currently, this issue appears to be adding two days to the rollover date for Atlantis, which would result in a slightly delayed rollout of the stack to Pad 39A. However, should that become the case, eight contingency days are currently available at the pad – if required.

The rollout date for STS-125 is sooner than that normally scheduled in a shuttle flow, due to the LON (Launch On Need) requirement of having Endeavour on Pad 39B at the time Atlantis launches. This has afforded STS-125’s pad flow to have over a week of contingency time in the nominal flow.

‘Evaluation of the schedule for potential impacts, if any, to the targeted Orbiter/ET mate date of 8/18 continues,’ added processing information. ‘Tracking approximately two days down on orbiter mate on August 18 and/or rollout to the pad. Have eight days of contingency at the pad if do rollout late.’

STS-125 is now heading into the business end of the paperwork requirenments to approve the mission for flight, opening with Thursday’s Program Requirements Control Board (PRCB) meeting, which will discuss the current CR (Change Request) relating to the launch dates for STS-125 and STS-126.

Managers will hear from all related departments on the current status of the flows, so as to ascertain if they will be able to move up the launch date of Atlantis – as far as October 5 – from what is currently October 8.

Every day gained will then be translated to moving Endeavour’s STS-126 launch date to the left, for the purpose of adding flexibility in her launch window – which is restricted by the November 25 Beta Angle cut off.

With both External Tanks (ET-127 in mating operations – and ET-129 arriving at KSC on Monday) adding confidence in the timelines, the PRCB may be able to approve the launch date changes. A few other factors, should as STS-125’s flight hardware arrival at the pad by early next week, are still in play.

The recent shutdown of the Johnson Space Center (JSC), due to Tropical Storm Edouard didn’t help, with two and a half days lost by some related departments.

‘Because of Tropical Storm Edouard, shut down training for two and a half days (because of graceful shutdowns and recovery),’ noted Mission Operations. ‘Looking at impact to training schedules and crew loading. Will have an answer on Monday or Tuesday. Could impact ability to support manifest CR for STS-126.

‘In regard to Tropical Storm Edouard, discussed hardware safing impacts with Engineering and contractor, ‘ added EVA. ‘Can recover from this and do processing for both STS-125, STS-400 and STS-126, but will be late for on-dock dates for reviews.

‘Will meet bench reviews and actual flight shipment dates. No significant impacts; just challenges to work schedules.’

Ultimately, the Agency Flight Readiness Review (FRR) will set the final launch date for STS-125 on September 22, though managers will have a good grasp on the status of the projected timelines by Thursday’s PRCB meeting.

STS-125 briefings are already taking place, with Mission Management Team (MMT) co-chair Leroy Cain noting a positive reaction to a Hubble mission overview at NASA HQ during the week.

‘HST briefings went very well and were well received. By the time they reached the end of agenda when the SRB was to present, they didn’t need to present, just gave a verbal because everyone was already in agreement with what had been presented,’ Cain noted on the latest Shuttle Stand-up/Integration report.

‘Overall, the presentation was well received. Good job by everyone.’

L2 Members: Refer to TAG keyword ‘STS-125’ for daily processing updates, baselines and presentations, etc.

Endeavour STS-400/STS-126 Latest:

Endeavour’s flow remains on track, with only one issue in work inside OPF-2, specifically relating to a problem with an Inertial Measurement Unit (IMU 1), which will be replaced.

The IMUs consist of an all-attitude, four-gimbal, inertially stabilized platform, and provide inertial attitude and velocity data to the GN&C software functions. Navigation software uses the processed IMU velocity and attitude data to propagate the orbiter state vector.

Guidance uses the attitude data, along with state vector from the navigation software, to develop steering commands for flight control. Flight control uses the IMU attitude data to convert the steering commands into control surface, engine gimbal (Thrust Vector Control) and reaction control system thruster fire commands.

Although flight could be accomplished with only one, three IMUs are installed on the orbiter for redundancy. The IMUs are mounted on the navigation base, which is located inside the crew compartment flight deck forward of the flight deck control and display panels. The inertial sensors consist of two gyros, each with two degrees of freedom, that provide platform stabilization.

‘During IMU Calibrations, while taking IMU 1 to operate, a ‘Platform’ fail indication was enunciated,’ noted processing information. ‘IMU 1 was taken down then brought back up to operate and the failure repeated. IMU Calibration is on hold pending R&R of IMU 1.’

Weekend work on Endeavour includes continued TPS work, surrounded by ongoing closeouts of the orbiter. Work is also taking place on the replacement of a poppet on an Auxiliary Power Unit (APU).

‘FWD/MID/AFT closeouts continue,’ added processing information. ‘QD (Quick Disconnect) mates and leak checks and pre-ops performed in support of the APU Poppet R&R. B Hatch Seal R&R continues next week.’

Endeavour’s SSMEs (Space Shuttle Main Engines) are also undergoing their final checks, following their recent installation.

‘STS-126/OV-105 – went into aft to do harness inspections. Engines 2 and 3 are acceptable. Engine 1 required minor adjustments which were completed,’ noted Pratt & Whitney Rocketdyne/KSC. ‘Gimbal clearance test scheduled for August 14.’

The latest highlight to Endeavour’s mission milestone has been the great work by the Michoud Assembly Facility (MAF) in New Orleans, who managed to ship External Tank ET-129 on the timeline to aid the potential advancement of the launch date for STS-126. The tank is expected at KSC on Monday.

‘Liberty Star and ET-129 departed Gulfport, MS and are scheduled to arrive on Monday at 8:00 a.m,’ added the latest Stand-up. ‘Mr. Shannon thanked the entire team for having ET-129 out early. STS-126 ET/SRB Mate and Orbiter Rollout Review will occur late August, mid September.’

Meanwhile, managers are awaiting an analysis report from Italy next week, with regard to the potential increase in payload that can be added to Endeavour’s already-heavy ‘Leonardo’ Multi-Purpose Logistics Module (MPLM).

‘Expecting STS-126 sensitivity analysis from Alenia next week. This is four different increments (250, 500, 750, and 1000 lbs of additional mass on MPLM),’ added Flight Operations & Integration at the Johnson Space Center (JSC).

‘Looking to turn this around by August 25, for the Loads Panel to say whether they are okay with the sensitivity study, determine whether a VLA (Verification Loads Assessment) is required or not, and to potentially down select one of the increments if there’s a falloff point.’

L2 Members: Refer to TAG keywords ‘STS-400’ and ‘STS-126’ for daily processing updates, baselines and presentations, etc.

Discovery STS-119 Latest:

With Discovery now deep in STS-119 processing, following her hugely successful STS-124 mission, progress towards her February, 2009 mission is proceeding to plan, with only another challenge to the shipping date of her External Tank (ET-130) in focus.

As with all flows, an element of troubleshooting on Discovery was ably dealt with by her United Space Alliance (USA) engineers, centering around an issue with the Nose Landing Gear (NLG) Uplock – related to when the gear is raised, and confirmed as ‘locked’ into place.

‘It was determined that additional materials (washers) were needed to complete the task,’ noted processing information. ‘NLG was cycled up to verify system working properly; the Uplock light stayed on and all checked out. The NLG was left up to support TPS operations on the NLG door.’

Other work being carried out in OPF-3 relates to the mod to her TPS for the Boundary Layer Transition test, and the continuing fastener installation on Windows 1, 5 and 6 – a new modification that has been overviewed in an expansive presentation that was acquired by L2 – and will become an article in the near future.

Discovery will receive the same SSMEs that flew with her uphill during STS-124, with Pratt & Whitney Rocketdyne/KSC currently putting the three engines through an extensive check inside the nearby engine shop.

‘STS-119/OV-103 engines are being worked in engine shop. Engine 1 (2048) – completed avionics checkouts and into big can leak checks. Engine 2 (2051) – securing from installing a nozzle. Engine 3 (2058) – securing final electrical connects. Will begin avionics checkouts on this engine.’

Build-up work on the booster segments that will be stacked in the VAB in the latter part of the year is also taking place at KSC, following delivery from ATK in Utah. However, all eyes are on ET-130, which was over four weeks down on its required delivery date from MAF just last month.

As always, MAF engineers are now starting to catch up on the timeline, aided by the shipping of ET-127 and ET-129, allowing resources to move to Discovery’s tank production.

‘ET-130 Tank is processing well. Critical path runs through ice/frost ramp base applications, all of which were sprayed and in trim now,’ noted Lockheed Martin/MAF. ‘In process of putting crossbeam assembly on hardware.’

L2 Members: Refer to TAG keyword ‘STS-119’ for daily processing updates, baselines and presentations, etc.

Downstream ETs and MAF Latest:

Two more tanks are also moving towards the latter part of their production, in preparation for their 2009 flights with STS-127 (Endeavour) and STS-128 (Atlantis).

‘ET-131 (STS-127) Tank is in Cell A. In process of working injections,’ added the report. ‘Working pocket sprays on H2 tank/intertank flange. ET-132 (STS-128) LOX intertank assembly is in process.’

The achievements of the MAF workforce since Return To Flight has rightly earned praise from throughout the Space Shuttle Program. Sadly, with the transition from Shuttle to Ares, many workers are about to be laid off at the New Orleans facility.

Notifications of redundancy will be sent out to employees at the end of the week, handing them just two weeks notice of losing their jobs. This move is being made regardless of efforts to extend the shuttle program by two years, and very serious problems with the design of the Ares I launch vehicle.

L2 members: All documentation – from which the above article has quoted snippets – is available in full in the related L2 sections, updated live.

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