posted 10-10-2007 04:56 PM               

The issue will be decided at the Flight Readiness Review.

posted 10-10-2007 04:58 PM               

quote:

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02:00 PM, 10/10/07, Wing leading edge issue assessed

NASA managers met for a program-level flight readiness review before a headquarters-level review next Tuesday. Among the topics up for discussion today was a potential issue with the ship's wing leading edge panels.

The reinforced carbon carbon panels protect the shuttle's wings from the most extreme heating during re-entry when temperatures exceed 3,000 degrees Fahrenheit. A breach in Columbia's left wing leading edge led to the shuttle's destruction in 2003.

Engineers believed a process known as oxidation could lead to a known type of degradation in a protective coating on the panels. But agency officials say recent testing indicates that may not be the root cause.

That could be a problem for NASA because it would indicate engineers do not fully understand what causes the degradation and, as a result, how such degradation might evolve over time.

Using a technique called thermography, Discovery's RCC panels were inspected as usual prior to the orbiter's roll out to the launch pad last week. Three of the shuttle 44 leading edge panels showed defects that have been in place for the last few flights.

Thermography data from each of those flights shows the defects have not significantly changed over time and there is no reason to expect any major changes during Discovery's flight. But the new test results have raised questions about NASA's ability to predict how such defects might worsen over time.

The shuttle's wing leading edge panels cannot be inspected at the launch pad. But it is not yet known whether any additional inspections might be required.

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posted 10-10-2007 09:20 PM               

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Originally posted by tncmaxq:
I thought a decision was due by tonight (Wednesday) but so far I have not heard anything definitive. I hope a final decision is not put off until part 2 of the FRR next week.

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quote:

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Replacing the panels would require moving Discovery off the launch pad and back to its hangar for repairs, work that likely would delay launch for weeks if not longer. A decision on how to proceed is expected next week, after a headquarters-level flight readiness review Tuesday.

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posted 10-11-2007 12:45 AM               

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Using a technique called thermography, Discovery's RCC panels were inspected as usual prior to the orbiter's roll out to the launch pad last week. Three of the shuttle 44 leading edge panels showed defects that have been in place for the last few flights.

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And the shuttle, despite Columbia, is flying with "defective" RCC panels. That's simply lovely. Same thing happened with the SRB's O-rings (Challenger) and loose foam (Columbia). But I'm no engineer.

posted 10-11-2007 03:03 AM               

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Originally posted by cspg:
And the shuttle, despite Columbia, is flying with "defective" RCC panels.

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NASA's Engineering and Safety Center has a similar job to the mechanic: it's their position that if something is off-nominal, it should be fixed. It is then the responsibility of the shuttle program to weigh the data and decide how best to proceed.

Unlike the problems that led to the losses of Challenger and Columbia, flying Discovery as is would not be in violation of any flight rules. Remember, the Engineering and Safety Center called for the RCC panels to be replaced due to a lack of information, rather than a known, existing problem.

posted 10-12-2007 07:31 AM               

I haven't had the guts to tell my wife there is an issue with the launch....

posted 10-16-2007 07:51 PM               

"We're ready to go and proceed with the launch," said NASA chief engineer Christopher Scolese, at the start of a press briefing, following the STS-120 flight readiness review.

posted 10-16-2007 10:47 PM               

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NASA Gives "Go" for Space Shuttle Launch on Oct. 23

NASA senior managers Tuesday completed a detailed review of space shuttle Discovery's readiness for flight and selected Oct. 23 as the official launch date. Commander Pam Melroy and her six crewmates are scheduled to lift off at 11:38 a.m. EDT on the STS-120 mission to the International Space Station.

Tuesday's meeting included a discussion about concerns raised by the NASA Engineering and Safety Center regarding the reinforced carbon carbon on three of Discovery's wing leading edge panels. This issue initially was brought before the Space Shuttle Program during a two-day, preliminary review held last week to assess preparations for Discovery's mission.

"After a thorough discussion and review of all current engineering analysis, we have determined that Discovery's panels do not need to be replaced before the mission," said Associate Administrator for Space Operations Bill Gerstenmaier, who chaired Tuesday's meeting.

During the shuttle's 120th mission, the shuttle and station crews will work with flight controllers at NASA's Johnson Space Center, Houston, to add a module to the station that will serve as a port for installing future international laboratories. The Harmony module will be the first expansion of the living and working space on the station since 2001. The upcoming mission also will move the first set of solar arrays installed on the station to a permanent location on the complex and redeploy them.

The 14-day mission includes five spacewalks - four by shuttle crew members and one by the station's Expedition 16 crew. Discovery is expected to complete its mission and return home at 4:47 a.m. EST on Nov. 6.

Joining Commander Melroy on STS-120 will be Pilot George Zamka and mission specialists Scott Parazynski, Stephanie Wilson, Doug Wheelock, Daniel Tani and Paolo Nespoli of the European Space Agency. Tani will remain aboard the station and return with the STS-122 crew, which is targeted to launch Dec. 6. Current Flight Engineer Clayton Anderson will return to Earth on Discovery after nearly five months on the station.

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posted 10-17-2007 12:53 AM               

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Shuttle boss confident suspect wing panels safe

Senior NASA managers today cleared the shuttle Discovery for launch Oct. 23 on a critical space station assembly mission, concluding concern about the integrity of a protective coating on three of 44 wing leading edge panels did not warrant a lengthy delay. While there were no official dissenting opinions, NASA's chief engineer opted to write down his concerns about the decision to proceed with flight and a NASA engineering panel stuck to an earlier recommendation to replace the panels in question.

In a worst-case failure, one in which some unknown mechanism caused the protective coating to somehow come off after the crew's normal heat-shield inspections in orbit and before peak heating during re-entry, the shuttle could suffer a catastrophic leading edge burn through. Replacing the panels in question would eliminate the threat but the work would delay launch for two months or more.

NASA is attempting to complete the international space station and retire the shuttle by the end of fiscal 2010. At a news conference late Tuesday, Hale did not address how the prospect of a long delay might have played into the launch decision. But he made it clear he believes it is safe to proceed with Discovery's flight while testing continues, saying there is no engineering data to support the worst-case scenario.

"We certainly explored it in a great deal of depth," Hale said. "Everybody got to ask questions, everybody got to give their understanding of it down to the working-troop level. And at the end of the day, the flight readiness review board decided we were in an acceptable risk posture to go fly. Which is not to say we completely and perfectly understand the problem that's been laid out. We're going to continue to work very hard on it as the data comes in. We will continually re-evaluate our position from flight to flight and if the risk grows to an unacceptable level, we will take action, whether that's to change some hardware or to delay some flights while we do testing or what have you.

"I really think this was a credit to the lessons that we learned since Challenger and Columbia to be able to listen to all the opinions, to think very clearly about what they mean, apply some critical thought processes and, I trust, come to a good decision that provides us with an acceptable reason to go fly. We have a very important mission ahead of us and the crew is going to have a very intense time on orbit. We need to focus on what they are getting ready to do... because it's absolutely critical to the next stage of building the international space station which is, after all, the reason for which we're flying the space shuttle."

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posted 10-17-2007 10:20 AM               

The engineering panel did their job as intended, but at the end of the day it is still the managers that have to make the final hard decisions. This isn't the first time it has happened in the space program (not just shuttle), nor will it be the last. There are many instances where the decisions made were correct. But it is the failures that get the headlines when things go wrong.

If I were an astronaut, knowing the risks I would still probably fly since there are plenty of other things that could kill me before this item becomes a problem (which I don't think it will).

posted 10-18-2007 08:20 AM               

Here's a question that's relevant to the situation.

What would NASA do if one of the astronauts due to fly on the next mission refused to fly because they were uneasy about the managements decision?

posted 10-18-2007 09:08 AM               

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Originally posted by CJC:
What would NASA do if one of the astronauts due to fly on the next mission refused to fly because they were uneasy about the managements decision?

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I think management would take the crew's concerns seriously, particularly if the CDR expressed concerns. It would have to be a pretty serious situation to make it worthwhile to fall on your sword, though, as there will likely be an impact on future flight assignments.

Ultimately, NASA management has to balance safety against mission accomplishment and manage the risks as well as possible until the ISS is completed.

I think the pressures at NASA are different today than they were in the 80's (an outsider's opinion). In the 80's, the pressure was on to get the flight rate up to 20-per-year to make the shuttle pay for itself. Today, the pressure comes from figuring out how to best complete ISS construction in as few flights as possible so we can retire the shuttle and move on. Management must be keenly aware that any accident will bring the program to a screeching halt for the foreseeable future.