Launch Date Announced for STS-117
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After a two day Flight Readiness Review in Florida, space shuttle managers have announced an official launch date for STS-117 to be June 8, 7:38 PM.
The launch window will run in two parts - from June 8th to the evening of June 12th when the shuttle must stand down for a June 14th Atlas launch. After that the windows opens again on the 17th. This first opening gives the standard four attempts in five days. If they have not launched by the 12th, they will replenish things such as liquid oxygen and hydrogen for the fuel cells to prepare for the 17th attempt.
Senior managers reviewed all of the repairs to the external tank and feel confident that there will be no issues of foam loss from the repairs. Shuttle Manager Wayne Hale cited that these repairs have been made and flown hundreds of times in the past with no problems.
Another of the topics raised during the two day meeting was one involving bolt inserts which hold low-pressure turbopumps to housings inside the orbiter's main engines.
The concern stemmed from an incident at NASA Stennis where one of the main engines was being tested. One of the fourteen inserts was corroded and pulled out of its bolt hole during installation.
This was the eighth time this has occurred at Stennis during the shuttle program. Failure has never occurred during engine test firing or flight and all the inserts which failed were older than sixteen years - far older than the ones on Atlantis.
Additionally - NASA had ordered all inserts on the orbiters to be replaced with oversize versions treated with anti-corrosion material. The inserts on Atlantis are from three to nine years old and their status was verified through boroscopic inspections, showing them to be in good condition.
The shuttle's main engines are fed by liquid oxygen and liquid hydrogen. The engines are ignited 6.6 seconds before booster ignition and are used during the eight and a half minute ride to orbit. The low pressure turbopumps are used to boost liquid oxygen pressure to the engines, allowing a high pressure oxidizer turbopump to operated at high speeds without the risk of running dry.
The shuttle's main engines create a combined maximum thrust of more than 1.2 million pounds.
The STS-117's eleven day mission will install the second starboard truss segment, S3/S4, to the International Space Station (ISS). The truss will be attached to the first starboard truss segment, S1. This will be ISS assembly mission 13A.
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The crew include Commander Rick Sturckow, Pilot Lee Archambault and mission specialists Patrick Forrester, Steven Swanson, John "Danny" Olivas, Jim Reilly and Clay Anderson, who will launch on the shuttle but remain on the station to begin a long-duration flight. Expedition 15 Flight Engineer Suni Williams, who has been aboard the station since December 2006, will return home on Atlantis.
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The crew will conduct spacewalks to install the new solar arrays, an exact copy of those installed on the station's port side. Once deployed, the arrays track the Sun and generate power to the station.
The STS-117 crew hopes to learn from previous problems experienced on earlier missions installing and deploying these arrays.
During the STS-115 mission last September, the crew experienced problems just removing the ten foot rotary joint which turns the arrays, out of the shuttle bay. The crew had a difficult time removing the bolts which keep the joint from shifting in the shuttle's cargo bay during launch. It took twenty minutes and two astronauts just to remove one bolt. Learning from that unpleasant experience, the crew is now equipped with a torque multiplier which can be used wherever there are troublesome bolts.
STS-116's crew had difficulty retracting a solar array which had been in use for over six years. The old array must be retracted to allow the new array to freely move and track the Sun. It took STS-116 more than 71 attempts and an additional spacewalk to finally get the old array to fold back into its box.
The original plan was for the arrays to be folded by ground command while all the astronauts were inside the station. But flight controllers now are working on a plan that would have Forrester and Swanson ready to assist with the folding during the second spacewalk of the mission. And if that doesn't do it, Reilly and Olivas could give it a try during the third spacewalk.
More information can be found at:
NASA's STS-117 Mission page
NASA's Space Shuttle