Endeavour has entered the three day countdown for what is likely to be her final ever launch. No issues are in work ahead of the next key status review – the L-2 Mission Management Team (MMT) meeting – as engineers dive into the complex ballet of S0007 operations, hopefully ending with the successful launch of STS-134’s packed mission to the International Space Station (ISS).
With a large part of Easter requiring no work on the stack out at Pad 39A, Endeavour hit S0007 operations on time at 2pm local time on Tuesday, having come out of a relaxed pad flow due to the large amount of contingency built into the schedule because of the slip of the launch date by 10 days.
The delay was caused by the surprise decision to give priority to the Russian resupply ship Progress M-10M, which is set to launch from the Baikonur Cosmodrome on Wednesday morning. Docking on Friday needs to avoid any major mishap to allow Endeavour to launch.
Out at the Pad, S0071, Hyper/MPS (Main Propulsion System) pressurization for flight was successfully completed, while final Orbiter aft closeouts are coming to a close. This included the installation of the Aft 50-1/2 doors and the final aft confidence test.
“OV-105/SRB BI-145/RSRM 113/ET-122 (Pad-A): S0007 Launch Countdown: Call to stations is scheduled for 1330 EDT. Milestones for today include: DPS (Data Processing System) configuration. GO2/GHS cross country line pressurization and PRSD (Power Reactant Storage and Distributation) preps,” added the NASA Test Director (NTD) pad flow update (L2) on Tuesday.
“Milestones for Wednesday include: Orbiter and SRB PIC (Booster electronics) tests and SRSS S&A device verification. PRSD load and offload.”
The operation was given the green light following the final hands on work with STS-134’s primary payload, the AMS-02 (Alpha Magnetic Spectrometer-02), involving the removal of the covers from the star trackers and final walkdowns of the highly scientific payload. Endeavour is also carrying the Express Logistics Carrier 3 (ELC-3) to the orbital outpost.
L-1 (Thursday) will be highlighted by the retraction of the Rotating Service Structure (RSS), revealing Endeavour in preparation for Friday’s all-important tanking.
No issues are expected, although – as per usual – the Ground Umbilical Carrier Plate (GUCP) was checked for leaks, after its associated vent arm assembly was battered by high winds during severe storm weather at the end of last month. Checks on the hardware show the system should perform as advertised during tanking.
“Milestones for Thursday include: Comm activation. RSS move to park. Tanking is scheduled to begin Friday morning at 0622 EDT. Launch is scheduled for Friday, at 1547 EDT.”
With no issues reported of late, KSC Ground Operations reported to the latest Shuttle Standup/Integration meeting in Houston that all is on track for the start of the countdown on Tuesday.
“OV-105 (STS-134) Completed the ordnance connections on Monday night/Tuesday. COPV (Composite Overwrap Pressure Vessels) pressurization to open the Pad. The aft closeouts will be completed. Working SRB (Solid Rocket Booster) closeouts. In good shape; will start the countdown on Tuesday.”
Final preparations for the launch ranged from Endeavour’s engines, to the return of her boosters, with all departments reporting in that they expect to be in a good stance – with the final status expected to be overviewed by the L-2 MMT at KSC on Wednesday.
“SSME (Pratt & Whitney Rocketdyne/KSC) All the closeout activity at the Pad is going well. Will be able to help support getting the aft closed and get the aft snapshot. Will be ready to support count,” added notes on the Standup report.
“The Corp of Engineers has agreed to work to eliminate the shoal on the west end of the loch that is inhibiting ship operations. They believe they can get it cleared by the time the ships are needed for STS-134 retrieval. Even if it is not complete in time, there are contingency plans in place.
“KSC Launch Integration Manager (NASA/KSC): The L-2 Review is next Wednesday at 9:00 a.m. ET.”
The STS-134 crew – lead by Commander Mark Kelly – also arrived at KSC’s Shuttle Landing Facility (SLF) on Tuesday, with notes from the Flight Crew department and Mission Operations confirming their readiness, which was completed with a final run of simulations – noted as “final ascents” – prior to jumping into their T-38s for the flight from Houston to Florida.
The weather for launch is currently 80 percent go, with the only concern relating to a potential crosswind violation, a constraint due to the requirement an orbiter can return to KSC in the event of a Return To Launch Site (RTLS) abort scenario.
“Tanking weather will be cloudy, but favorable, and by launch time, the only issue is the wind will shift to the north-northeast, causing a concern for a Shuttle Landing Facility (SLF) crosswind violation,” noted the latest weather update provided by the NTD.
“Our primary concern for launch is a SLF crosswind violation. The concern for a SLF crosswind violation increases the following day as the winds shift more easterly, and by Sunday, the winds become more favorable from the east-southeast.”
(Numerous articles will follow. L2 members refer to STS-134 coverage sections for internal coverage, presentations, images and and updates from engineers and managers. Images used: Larry Sullivan MaxQ Entertainment/NASASpaceflight.com, L2 Presentations and nasa.gov).