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Shuttle propulsion system inspections ordered BY WILLIAM HARWOOD STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION Posted: April 5, 2007 With external tank repairs in high gear, NASA managers today ordered removal of the shuttle Atlantis's three main engines for inspections to make sure no contamination is present in the ship's hydrogen fuel lines. While engineers are hopeful the work can be completed under the umbrella of external tank repairs, getting Atlantis off before its May launch window closes remains a major challenge. The latest issue involves small bits of silicon rubber RepliSet, used to help detect cracks in main propulsion system fuel line flow liners, that were found in the shuttle Discovery recently, prompting concern about similar contamination in Atlantis and Endeavour. The RepliSet technique is used before and after a shuttle flight to make exact three-dimensional impressions of the fuel line flow liners to look for signs of potentially catastrophic cracks. Engineers apparently missed a small bit of the material after impressions were made in Discovery's flow liners between two of its most recent flights. NASA managers want to make sure no similar contamination is present in the main propulsion systems of the other orbiters. "This was an easy decision to make," said a NASA official. "No one wants contamination in the propulsion system." Assuming no other problems are found, engineers say Atlantis's main engines can be removed, the inspections carried out and the engines reinstalled without impacting when the shuttle will eventually take off on a space station assembly mission. The long pole in the tent remains the work needed to repair extensive hail damage to the foam insulation on the top of the ship's external fuel tank. Senior NASA managers plan to meet April 10 to discuss whether to press ahead with tank repairs for a possible May launch or whether to switch Atlantis to the external tank slated for use by the shuttle Endeavour for the next flight on the manifest. That tank, ET-117, is scheduled to arrive at the Kennedy Space Center on Friday. Switching Atlantis to ET-117 would delay launch to mid June. NASA managers want to stick with the current tank, ET-124, if at all possible. Astronaut Steve Swanson, awaiting his first flight aboard Atlantis, told a reporter today he was not concerned about flying with a repaired external tank. "I'm not worried," he said. "I've talked to the engineers and seen the tank and the repairs they are doing. They are doing a very good job. After talking to them, I believe when they tell me the tank is ready, it is going to be just as good as a brand new tank. "It really doesn't matter to me on which tank (we fly)," he said. "When they are both ready to go, they're both going to be equal, the same amount of safeness, if you want to call it that. I'm happy with either one." Assuming the ET-124 repairs can be completed in time, the earliest Atlantis could take off using the current tank is believed to be around May 15, after the launch and docking of an unmanned Russian Progress supply ship. And that assumes engineers can compress the current shuttle processing schedule. The shuttle's launch window, based on temperature constraints related to the station's orbit, closes around May 21 and reopens June 8. Given the extensive foam repairs required, many engineers believe NASA will be hard pressed to get Atlantis off the ground in May, but they are still assessing the work remaining and the results will be presented April 10. "It looks pretty bleak," one senior engineer said today. "Having to pull the engines, the ET repair and more important, getting comfortable with the ET repair ... (a May launch is) becoming more and more unlikely." Shuttle planners, meanwhile, continue to assess proposed downstream manifest changes that would move two missions from Atlantis to Discovery and one from Discovery to Atlantis. By changing orbiter assignments, the agency can still get four flights off this year if no other major problems develop. The proposed changes, which require space station program concurrence, will be discussed during a meeting April 16. The changes, if approved, would result in the following near-term launch schedule (NOTE: assumes STS-117 stays with ET-124; the target date for STS-117 - May 11 - is a place holder; the actual date will depend on the progress of tank repairs): 05/11/07 - STS-117/ISS-13A/Atlantis/ET-124 07/14/07 - STS-118/ISS-13A.1/Endeavour/ET-117 10/13/07 - STS-120/ISS-10A/Discovery (was Atlantis)/ET-120 12/06/07 - STS-122/ISS-1E/Atlantis (was Discovery)/ET-125 02/14/08 - STS-123/ISS-1JA/Endeavour/ET-126 04/24/08 - STS-124/ISS-1J/Discovery (was Atlantis)/ET-128 08/28/08 - STS-125/Hubble servicing/Atlantis/ET-130 |
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MISSION INDEX |
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This documentary looks back at Apollo 7, the first manned flight of the Apollo program. Apollo 7 was designated as the essential engineering test of the spacecraft before the ambitious lunar missions could be attempted.
NASA astronaut Suni Williams will run the Boston Marathon on a treadmill aboard the International Space Station. To preview the event, Williams, an accomplished marathoner, and Expedition 14 commander Michael Lopez-Alegria talk with The Boston Globe and the
New England Sports Network.
After nearly a year in space, the European Retrievable Carrier (EURECA) satellite was plucked from orbit and stowed aboard Endeavour for return to Earth during STS-57. The June 1993 mission also featured the first flight of the commercial Spacehab module outfitted with a range of microgravity experiments for the crew to use. A spacewalk to demonstrate working on the end of the shuttle robot arm was performed as well.
Working in two shifts around the clock, the astronauts of shuttle mission STS-56 conducted extensive observations of the Earth's atmosphere using the ATLAS 2 payload in the spring of 1993. The SPARTAN Sun-studying satellite was deployed and then retrieved during Discovery's flight too. The crew narrates the highlights in this presentation.
Space shuttle Endeavour lofted another Tracking and Data Relay Satellite into orbit for NASA during a January 1993 mission. An Inertial Upper Stage boosted the craft toward geosynchronous orbit. Other highlights from STS-54 included a mobility-testing spacewalk and an educational project to demonstrate the physics behind toys in space. The crew narrates this post-flight film.
The Laser Geodynamics Satellite (LAGEOS), a small ball-shaped spacecraft designed to help earthquake research by monitoring the movements of the Earth's crustal plates, was launched from space shuttle Columbia in October 1992. The crew of STS-52 narrate the highlights of the mission, which included Canadian and microgravity experiments.