Space Shuttle Atlantis LAUNCH HAS officially BEEN SCRUBBED. This post contains a full log of the order of events from tanking begin at 5:55am up until conclusion of the first post-scrub press briefing at around 8:30am.
Today should have seen the second launch attempt for space shuttle Atlantis' STS-122 mission to the international space station ISS. Atlantis should have deliver the European Columbus lab module to the orbiting complex. Read why this now doesn't happen...
Tanking has begun at 5:55a ET and so far everything is proceeding nominally. At around 6:40a a first status of the ECO sensors, responsible for a three-day launch scrub, is expected. All for sensors must work perfectly today, otherwise the launch will be scrubbed. If all goes well, Atlantis will lift-off at 3:21pm ET, within a very short one-minute launch window. Weather looks favorable, with just a 20% chance of weather prohibiting the launch.
Liquid hydrogen sensor number 3 has failed!
At 6:25a, guys in the control center look relaxed. Let's hope it remains that way...
All four ECO sensors now indicate "wet". This is good, but not yet a relief. The problem that caused launch scrub on Thursday did only show up after a series of test commands were sent to the sensors. As of my information, we are still about half an hour to an hour away from these checks.
6:47a: tanking has changed to "fast fill" mode. Last time, the ECO sensor problem occured 16 minutes into fast fill. According to the NASA TV commentator, we should get results of the sensor test in about half an hour.
6:52am: Liquid hydrogen sensor 3 has failed! A minute before that, the NASA TV commentator announced that all four sensors had passed the check, but then, he sadly had to announce that ECO sensor number three failed after a few seconds. Based on the information provided in yesterday's press briefing, a launch scrub is highly probable.
7:00am: NASA will tank for another half hour. The team is now doing troubleshooting. No launch scrub yet!
7:02am: NASA TV commentator: "the ground rules layed out that we have to have four sensors to proceed with launch. And we have had sensor number 3 fail. So, we are going to do some trouble shooting over the next half hour. At that point we would stop, asses whether we do any further testing at that point and then drain liquid oxygen. Liquid hydrogen will stay in filled configuration." ... "An official launch scrub has not yet been declared, but according to the plan, the rest of the morning is evolving into a tanking test."
7:09am: NASA TV: "The MMT has asked the propulsion console to come up with a time line on how long it would take to drain the liquid oxygen and then drain liquid hydrogen to 5%". "The mission management team will ... shortly ... talk about what our official status will be. Although we have not officially declared the scrub, the commit launch criteria does not permit to continue..."
7:13am: NASA TV: "We continue to fill the tank for another 15 minutes". Me: Note that this is not in support for a launch attempt but for troubleshooting purposes. As outlined yesterday, NASA will use the tanking to gather additional data, which hopefully provides more insight into the root cause of that problem. Let's hope that NASA manages to get that highly in demand data.
7:24am: NASA TV officially announces the launch scrub.
7:39am: The NASA homepage officially states that space shuttle Atlantis' Sunday launch has been scrubbed.
7:55am: Commentator announces that a short news briefing will be held within the next ten minutes or so. Meanwhile, the launch attempt has been converted into a tanking test. NASA is hopeful to retrieve some data pointing to the root cause of the ECO sensor problems. It was also noted that the failure scenario this time was different from what has been seen at the last launch attempt on Thursday.
8:00am: mission management team meeting set for 9:00am. Liquid oxygen tank is being drained.
I just picked up this picture from NASA TV. It shows members of the mission management team discussing after space shuttle Atlantis second launch attempt had been scrubbed.
8:14am: Press briefing begins. NASA launch director Doug Lyons is interviewed by public relations officer George Diller.
Mr. Lyons explained: "All the voltages had good readings as well. We were very excited. We thought we had a good system and ready to fly today. We continued monitoring and then we saw sensor number 3 go dry to wet, which was a failure." He added that based on the launch commit criteria set yesterday, that meant the launch had to be scrubbed.
As already said, today is now devoted to troubleshooting. Mr. Lyons: "We do have a troubleshooting plan in place. We stopped the flow on the liquid hydrogen (LH2) system and put it into a stable posture configuration. And we drain the liquid oxygen (LOX) tank, than we focus on LH2, we drain down to 5% and stop there and then monitor the system for four hours and see how these systems behave. Then we drain and secure the pad." I assume that this is done in order to see how thermal changes may affect sensors and their connections to the orbiter.
Mr. Lyons noted that the failure was not much different from Thursday's failure: "The only difference is sensor 3 and 4 failed Thursday, and today just sensor number 3. It failed in the same time frame and the same manner." It should be said, however, that every time before there was trouble with the ECO sensors, that trouble "magically disappeared" (to quote Wanye Hale) on second tanking. That was the rational for attempting a launch today. So something is different to previous experience.
Asked on how to proceed now, Mr. Lyons declined to comment: "We have a 9am mission management team meeting and discuss our options. It would be speculation at this time to try to make a guess on which direction we head. We have multiple options. We will put something together and then implement it after that meeting."
After the interview, NASA TV ended its coverage of today's launch attempt at 8:21 am. ET.
Press conference is whenever the mission management team meeting concludes. My personal guess is this will be in the late afternoon/evening time frame.
I, too, will now conclude coverage of the launch attempt on this blog page. I'll now stick to other things and wait for the press conference. Should exciting news happen, I hope to pick it up. If so, I'll create a new posting on my blog. Thanks everyone for reading.
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