STS-135: Atlantis on track for Tuesday’s S0007 launch countdown

by Chris Bergin

Atlantis is continuing to behave on Pad 39A as preparations for entering S0007 tasks – otherwise known as the three day launch countdown – remain on track, with the clock’s scheduled to start ticking backwards at 1pm local on Tuesday. STS-135 will mark the final scheduled Space Shuttle mission, although the actual duration of the flight is still being discussed.

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With what is hoped to be Atlantis’ final issue prior to launch behind her – relating to the changeout of a leaky Main Fuel Valve (MFV) on Space Shuttle Main Engines 3 (SSME-3) – engineers have been busy preparing the orbiter for the complex ballet of operations during the S0007 tasks.

This work has include the closure of her Payload Bay Doors (PLBDs) and the securing of the access doors located on her aft.

“Things continue to go well at the Pad. Over the weekend, completed the Engine #3 retests on the fuel valve that was changed out. Earlier in the week, all ordnance connects and changeouts were completed on the SRB and ET. Installed EMUs (Spacesuits) and completed the checkout,” noted KSC Ground Operations on the latest Shuttle Standup/Integration report (L2).

“The PLBDs were closed for flight. Today, work on the aft closeout continues. Continuing to put doors on the orbiter tonight (Thursday) on second shift. Got into the COPV (Composite Overwrap Pressure Vessels) pressurization last night, will wrap it up this morning (Thursday). Still on track for call to stations for S0007 Tuesday at 12:30 p.m. ET.”

Known as S0071 tasks, engineers pressurized Atlantis’ Main Propulsion System (MPS), SSMEs and Orbital Manuevering System (OMS) and Reaction Control System (RCS) over the course of Thursday.

“S0071 Hyper/MPS pressurization is underway Thursday morning. MPS/SSME helium tank press to flight pressure is complete and in stabilization. OMS/RCS GHe/GN2 press to flight mass is complete through stage 1 press. Stage 2 press is in work (and was completed after) several more hours,” added the NASA Test Director (NTD) flow update (L2).

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With the aforementioned closeouts in work, with the Mid-body/Payload closeouts complete and Payload bay doors were closed for flight, Atlantis is close to being in her flight configuration, with only the Aft flight door installation remaining.

Only one additional Interim Problem Report (IPR) – charged during S00071 tasks – has required future evaluation, albeit only from a paperwork standpoint.
“New IPR 0055: During helium system activation, the left hand helium regulator locked up at 268.9 psig and should be less than 268 psig,” the NTD report added. “No work will be required; however a potential waiver to OMRS (Operational Maintenance Requirements and Specifications) will be needed.”

Meanwhile, a GH2 and GO2 recharge at the storage battery continues to be in work, along with an upcoming LH2 storage tank replenishment, scheduled for Friday, via a wave of eight tankers. Atlantis and her engineers will then spend the Independence Day weekend preparing to enter the launch countdown on Tuesday afternoon.

“Preparations for S0007 Launch Countdown continue. CTS (Call To Stations) for launch countdown is planned for 1230 EDT on Tuesday, July 5. Launch T-0 is targeted for 1121 EDT on Friday, July 8.”

The four person STS-135 crew are scheduled to fly into the Kennedy Space Center (KSC) on Friday, where they will head into quarantine ahead of their mission.

As previously reported, the International Space Station Program (ISSP) have requested an additional day for the STS-135 mission, based around the work required to fill the Multi-Purpose Logistics Carrier (MPLM) with the preferred amount of downmass, an often-underestimated capability which will be practically off the cards once the Shuttle is retired.

“Agree to keep MPLM heaters off on way up and down,” added the DA Staff Notes (L2), referencing one of the savings which will be implemented to give Atlantis the best chance of having enough consumables to allow for the mission extension. “This will get documented. If don’t get the extra docked day, then won’t have time to fill up MPLM.”

Given Atlantis is the only orbiter to lack the Station-to-Shuttle Power Transfer System (SSPTS), the flexibility to gain the required consumable allowance for a mission extension will be tight.

Assets relating to both the launch and the recovery of the Solid Rocket Boosters are also preparing for their role, with both Freedom Star and Liberty Star in the local area.

The latter is currently undergoing radar calibrations, ready to monitor Atlantis’ ride uphill. Both ships will be involved with the recovery of the boosters.

The next managerial meeting will be conducted by the Mission Management Team (MMT) next week at the L-2 briefing, where managers will discuss any new issues in the flow, along with the final sign off of post-Flight Readiness Review (FRR) documentation, such as the Change Request (CR) which confirms the stringers on ET-138 are in the acceptable condition for flight.

“The CR for the ET-138/STS-135 stringer crack waivers was put into the system,” noted the ET Project at the Marshall Space Flight Center (MSFC). “The process is expected to go smoothly.”

All of the stringers on the LO2 and LH2 flanges of ET-138’s Intertank were inspected via X-Ray and Backscatter evaluations, following the recent Tanking Test. No issues were found, as was briefed at the Agency FRR this week, a review which MMT chair LeRoy Cain praised via the standup report.

“We had a great FRR this week. We are clearly on the right path and ready to go toward STS-135 launch on Friday of next week. There are a couple of items that folks are finishing final closeout of, and obviously things are going well with the vehicle down in Florida. It was a great job getting to this point. We are ready to go. Have a good Independence Day.”

(Images: Via Larry Sullivan MaxQ Entertainment/ and L2 content. Further articles on STS-135′s status in work, driven by L2′s fast expanding STS-135 Special Section which is already into the FRR content and live flow coverage, plus more.

(As with all recent missions, L2 is providing full exclusive level flow and mission coverage, available no where else on the internet. To join L2, click here:

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