Atlantis – 8 July 2011 First Launch Attempt

STS-135 two hours before launch Image Credit: KSC TV Feed

At 6:44 AM Phoenix time (1344 UTC) launch is about 2 hours away. At the moment we are ‘no go’ due to cloud density over the launch site. NASA-TV is here, and the Kennedy Space Center video feeds can be found here for weather and pad cameras.
Weather 90 Minutes Before Launch Image Credit: KSC TV Feed
The countdown is at T-minus 20 minutes and holding, with a ten minute built in hold. At 7:21 AM Phoenix (1321 UTC) the count has resumed and will go down to T-minus 9 minutes for the next built in hold.

Ops Commit Criteria 60 minutes before launch. Image Credit: KSC Video

Weather is now a ‘go’. The Ops Commit Criteria are all green. The launch is now at T-minus 9 minutes, with a 41 minute built in hold. This will set up the launch, with the window opening at 15:22:13 UTC. The launch is expected at 15:26 UTC. The countdown will resume at 15:17:46 UTC Poling of the main systems is complete, and everything is go.

T-minus 4 minutes. Steering check of the three main engines. Solid rockets are armed. The auxiliary power units have been started. T-minus 2 minutes. T-minus 60 seconds. T-minus 31 seconds and a failure at the moment of hand-off to the internal computer. Retraction of the event arm confirmed. The count has resumed. And launch.

Launch
Image Credit: NASA TV

Seven minutes into the flight, all systems are go.

At eight minutes we have main engine cutoff and external tank separation.

All three APU systems and all three fuel cells are operating normally.

Atlantis will now begin chasing the International Space Station, anticipating docking two days from now.

Atlantis – The Last Space Shuttle Flight

STS-135 on the pad July 4th Image Credit: KSC TV Feed

Processing of the space shuttle Atlantis continues today, July 4th, in preparation for the July 8 launch. Here are the launch windows for Atlantis (times are UTC): 8 July – 1521-1531 9 July – 1459-1509 10 July – 1433-1443 After that is a five day period reserved for a Delta IV launch. The next launch window is 16 July beginning at 1211 UTC.

The primary objective of STS-135 is to deliver a Multi-Purpose Logistics Module (MPLM) carrying 9,500 lbs of cargo, a Lightweight Multi-Purpose Equipment Support Structure Carrier (LMC), and a Station Power Distribution Unit (SPDU). The LMC will carry the Robotics Refueling Payload to the ISS and return the failed Pump Module (PM) from the ammonia cooling system. Additional ISS equipment and supplies will be carried up. The current mission for Atlantis is to deliver as much stuff as possible to the Space Station before we come to rely on the Russian Soyuz M, European ATV, Japanese HTV, SpaceX Dragon and Orbital Sciences Cygnus resupply missions. A long history of the Atlantis missions can be found at NASASpaceFlight: Part One Part Two Part Three A complete guide to NASA TV coverage can be found here.

Major Overhaul – Replacing the Ammonia Pump Module on the ISS

August was a busy month for the crew of the International Space Station and the support teams on the ground. On Saturday, 31 July 2010 the Loop A Ammonia Pump Module (pictured at right) on the External Thermal Control System (ETCS – pdf) on the S-1 truss on the Integrated Truss Structure (Starboard side – diagram below) failed, cutting the main cooling capacity of the United States portion of the International Space Station by 50%. The Russian modules have their own cooling system. Station managers began shutting down a variety of systems and experiments on board the ISS in order to reduce the heat load to a level manageable by the Loop B ETCS on the P-1 truss (Port side). Two EVAs were scheduled to remove and replace (R&R) the Pump Module. The first for Thursday 5 August and the second no earlier than two days later.

Ammonia Pump Module Flown on STS-129 Image Credit: NASA

Image from the Interactive Guide to the Integrated Truss Structure
Image Credit: NASA

Planning for the first EVA eventually caused the spacewalk to slip to Saturday. The EVA tasks required working with numerous electrical cables and both internal and external cooling fluid lines prior to being able to remove the Ammonia Pump. The first EVA was scheduled to disconnect cooling lines and remove the failed pump module from the S-1 truss. Problems were encountered with one of the quick disconnect units on an ammonia line, and removal of the pump module was postponed until the second EVA. Doug Wheelock and Tracy Caldwell-Dyson began the second EVA at 7:27am Central time (9:27 EDT) on Wednesday 11 August. This time the quick disconnects for cooling and electrical connections went as planned. The two astronauts then successfully removed the failed pump module and stowed it.

Ammonia Pump Module Diagram Image Credit: forum.nasaspaceflight.com

External Thermal Control System Truss Diagram Image Credit: forum.nasaspaceflight.com

The third EVA began on Monday 16 August at 5:20am Central Time. Astronauts Doug Wheelock and Tracy Caldwell-Dyson then set out to unbolt the replacement Pump Module (PM) and place it in position on the S-1 Truss. Wheelock removed the bolts holding the new PM to ESP-2 (External Stowage Platform) and the Space Station Remote Manipulator System (SSRMS) then translated Wheelock and the 780 pound PM to the S-1 truss. Wheelock bolted the PM into place and Caldwell-Dyson mated several electrical connections, “waking up” the PM. Initial electrical testing prove the new PM was ready to go. Various fluid lines were reconnected and ammonia was reintroduced into the system. By Wednesday 18 August, the International Space Station was beginning to get back to normal. There were no yellow or red system lights on the status board. On Wednesday and Thursday, the major effort involved bringing the Columbus science module and the Japanese Experiment Module (JEM – “Kibo”) back online. The remainder of the month has involved bringing the various experiments back on line and testing the coolant systems in Loop A. Congratulations to the ISS team for successfully working the Pump Module failure. With three additional back up PMs on the Space Station, we can expect to see this scenario repeated. Lessons Learned will be carried forward by the ISS team. Current expectations are that the ISS will be in operation until 2020, and perhaps beyond that. There will be a lot more R&R of various systems as the years pass.

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