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'Outstanding' performance from Discovery's fuel tank BY WILLIAM HARWOOD STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION Posted: October 24, 2007 The shuttle Discovery's foam-covered external fuel tank performed well during launch Tuesday, NASA officials said today, shedding only a half-dozen pieces of insulation - all well after the period when such debris can pose an impact hazard - with no signs of damage to the orbiter's heat shield.
"We have not seen anything that would cause us any concern at all," he told reporters after an unusually short MMT meeting Wednesday. "We'll continue to look, we'll look at the solid rocket booster videos on Friday to make sure that's true, but there was nothing of any mass at all that was released during that (aerodynamically critical) time. Even the material that was released later on, we don't think it was anything that could have caused damage." Today, the Discovery astronauts inspected the shuttle's reinforced carbon carbon - RCC - nose cap and wing leading edge panels using a laser scanner and a high-resolution digital camera. While the analysis is not yet complete, engineers have not seen any obvious signs of trouble with any of the critical panels, including three that raised concern before launch because of degradation in a protective coating. "The performance of the tank was outstanding," Shannon said. "The tank really performed well. The RCC imagery, it was the same thing, no one has seen anything that was of any concern to them. They do a much more detailed analysis as the evening goes on, we'll continue to look at it, but there was really nothing. ... Right now we have no TPS (thermal protection system) issues at all." External tank No. 120 was jokingly referred to as "Frankentank" by NASA insiders because of extensive foam dissection and modification work carried out in the wake of earlier problems. ET-120 was assigned to the first post-Columbia mission and was fueled twice before being replaced because of problems with hydrogen tank fuel sensors. The tank was sent back to Lockheed Martin's Michoud Assembly Facility in New Orleans to serve as a test article in the wake of a major foam loss during the first post-Columbia flight. It later was returned to flight status and assigned to Discovery. Shannon said ET-120's performance during Discovery's launch was not a surprise, saying "I'm extremely confident in the tanks we're flying now, but we're just making them better." Of the half-dozen pieces of foam that fell from the tank after solid rocket booster separation, one was an 8-by-6-inch chunk near one of the forward bipod struts used to anchor the shuttle's nose to the tank. Shannon said this is the third flight in a row where foam has separated from that area, apparently due to a phenomenon known as "cryo-pumping." When air gets under the foam, either due to a crack or some other avenue, it liquifies because of the tank's ultra-low temperature. During launch, when the tank heats up due to atmospheric friction, the liquid can turn back into a gas with enough force to blow off small chunks of overlying foam. Shannon said engineers are unsure about what's going on in the area near the bipod strut. But given the timing of the releases, it does not pose an impact threat to the shuttle. "We didn't see anything new on this tank that surprised us at all," he said. "The performance was just better. We'll go look at that one little area and see if there's some collateral damage potentially that is causing that same area to pop off on three flights in a row. It's not a concern to us because of when it comes off but you'd like to understand what's going on so we'll go look at that. But overall, the tank performed extremely well." The Discovery astronauts plan to dock with the international space station early Thursday to kick off one of the most challenging orbital construction missions yet attempted. Here is a timeline of the final stages of the rendezvous (in EDT and mission elapsed time): DATE/EDT...DD...HH...MM...EVENT 10/25/07 01:08 AM...01...13...30...ISS crew wakeup 01:38 AM...01...14...00...STS crew wakeup 02:53 AM...01...15...15...Group B computer powerup 02:58 AM...01...15...25...Begin rendezvous timeline 05:45 AM...01...18...07...ISS in attitude for docking 05:55 AM...01...18...17...TI burn 06:31 AM...01...18...53...Sunset 06:31 AM...01...18...53...Zvezda module lights on 06:31 AM...01...18...53...ISS in rendezvous mode 06:45 AM...01...19...07...US arrays feathered 06:54 AM...01...19...16...Range: 10,000 feet 07:01 AM...01...19...23...Sunrise 07:02 AM...01...19...24...Range: 5,000 feet 07:08 AM...01...19...30...Range: 3,000 feet 07:12 AM...01...19...34...MC-4 rendezvous burn 07:16 AM...01...19...38...Range: 1,500 feet 07:17 AM...01...19...39...Rendezvous pitch start window open 07:21 AM...01...19...43...Range: 1,000 feet 07:24 AM...01...19...46...KU antenna to low power 07:25 AM...01...19...47...+R bar arrival; Discovery is directly below ISS 07:30 AM...01...19...52...Range: 600 feet 07:32 AM...01...19...54...Start pitch maneuver 07:32 AM...01...19...54...Noon 07:39 AM...01...20...01...RPM full photo window close 07:40 AM...01...20...02...End pitch maneuver 07:43 AM...01...20...05...Initiate pitch up maneuver 07:47 AM...01...20...09...RPM start window close 07:47 AM...01...20...09...Russian arrays feathered 07:54 AM...01...20...16...+V bar arrival; Discovery is directly in front of ISS 07:55 AM...01...20...17...Range: 300 feet 07:59 AM...01...20...21...Range: 250 feet 08:03 AM...01...20...25...Sunset 08:03 AM...01...20...25...Range: 200 feet 08:06 AM...01...20...28...Range: 170 feet 08:08 AM...01...20...30...Range: 150 feet 08:12 AM...01...20...34...Range: 100 feet 08:15 AM...01...20...37...Range: 75 feet 08:19 AM...01...20...41...Range: 50 feet 08:22 AM...01...20...44...Range: 30 feet; start station keeping 08:27 AM...01...20...49...End station keeping; push to dock 08:32 AM...01...20...54...Range: 10 feet 08:33 AM...01...20...55...Sunrise 08:33 AM...01...20...55...DOCKING
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THE FLIGHT DAY 2 HIGHLIGHTS MOVIE 