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Author
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Topic: STS-117: Left wing debris impact?
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Lunatiki
Member Posts: 237
From: Amarillo, TX, USA
Registered: Dec 2006
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posted 06-12-2007 07:32 PM
  
quote:
WASHINGTON -- A meteorite or space junk may have struck Space Shuttle Atlantis' left wing, according to NBC News space correspondent Jay Barbree.NASA recorded a hit on reinforced carbon panels 7 and 8 on the left wing. The panels keep heat from re-entry from burning the spacecraft.
http://www.nbc4.com/news/13490740/detail.html |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 06-12-2007 07:41 PM
This was more or less dispelled by Mission Management Team chair John Shannon during this evening's STS-117 mission briefing. A 1g impact was recorded by the RCC leading edge sensors today however it was only detected by one sensor. In the case of a real impact, they would expect to see other sensors detect the hit, just to a lesser degree, like with ripples on a pond. NASA has seen this before; on this mission alone they registered a similar single-instance .5g impact in a different area yesterday. What they suspect is happening is a thermal event, such as a panel flexing as it heats or cools. As Shannon explained, this is why they have late inspections scheduled on each mission and they will observe the area at that time, though they really don't expect to see anything. |
Lunatiki
Member Posts: 237
From: Amarillo, TX, USA
Registered: Dec 2006
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posted 06-12-2007 07:51 PM
Makes sense to me. I wonder why the NBC story didn't mention more. That's probably a stupid question. If there were indeed a chance of real damage, it would be a major story. I know the headline really caught my attention. Anyone know exactly how much stronger, on a percentage basis, the RCC panels are compared to the old leading edges on the wings? |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 06-12-2007 08:03 PM
quote:
Originally posted by Lunatiki:
Anyone know exactly how much stronger, on a percentage basis, the RCC panels are compared to the old leading edges on the wings?
There is no difference as there was no change to the the leading edge after the loss of Columbia. In fact, the same panels that were flying prior to STS-107 are still flying today. The post-accident efforts were focused on understanding and preventing foam loss, as well as detecting impacts and implementing repair techniques, rather than strengthening the orbiter (though there were some small areas that benefited from strengthened thermal tiles).
Edited by Robert Pearlman |
Lunatiki
Member Posts: 237
From: Amarillo, TX, USA
Registered: Dec 2006
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posted 06-12-2007 09:21 PM
So the area on Altantis's wing where the Columbia took a hit is the exact same as Columbia's was? No stronger? Another foam hit in the same area would do the same damage now? I guess I really missed something. That seems nuts. |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 06-12-2007 09:54 PM
Yes, the panels on Atlantis today are exactly the same in design as they were on Columbia on February 1, 2003. Here is what is different: - The external tank has been redesigned to remove the chance of foam separating from the bi-pod ramp, which is where the debris that impacted Columbia originated. Not content with stopping there however, NASA has redesigned and continues to improve other areas of the tank to reduce the chances of foam separating at times during flight when it is at most risk the orbiter.
- An inspection boom has been added to the shuttle's payload compliment to permit early and late inspections of the entire orbiter for any sign of damage, whether it is from ET foam, bird strike or micro-meteors. Furthermore, during launch, the shuttle is observed much more closely, including the use of on-board cameras attached to the ET and solid rocket boosters. NASA has also reached agreements with ground and space-based assets to assist in imaging the shuttle on an as-needed basis.
- Should it be necessarily, NASA has developed and tested multiple repair techniques for tile and RCC damage. Furthermore, they have developed the steps needed to guarantee a "safe haven" aboard the ISS for the shuttle crew and implemented the means to land the shuttle without a crew. NASA has also required another shuttle be ready to rescue a damaged shuttle's crew.
And these are just some of the improvements... suffice to say, what happened to Columbia could not happen again today under the same circumstances.
Edited by Robert Pearlman |
garymilgrom
Member Posts: 1966
From: Atlanta, GA
Registered: Feb 2007
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posted 06-13-2007 08:23 AM
>>implemented the means to land the shuttle without a crew.Robert could you expand on this please? I thought the orbiter was always capable of automated landings, but the crew preferred to manually fly it down. Has something changed? Thank you. |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 06-13-2007 08:52 AM
Most the shuttle landing procedures could be automated without any additional hardware, but there were a few activities that were, until recently, only manually-controlled. These included starting the auxiliary power units, deploying an air data probe, unstowing the landing gear and releasing its drag chute after landing. To land a unmanned orbiter, a 28-foot cable would connect an avionics bay in the middeck with the controls one level up on the flight deck. |
Lunar rock nut
Member Posts: 911
From: Oklahoma city, Oklahoma U.S.A.
Registered: Feb 2007
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posted 06-13-2007 09:39 AM
In the event of an unmanned landing. Would you enlighten us on the rescue proceedure? Especially if another shuttle went up to bring back the astronauts. How many astronauts would fly on the rescue flight to the ISS? CDR & PLT only,shutlle modified to bring back nine?Terry |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 06-13-2007 09:54 AM
A "Launch On Need" (LON) includes four crew members from the next scheduled flight. They would return the six or seven shuttle crew members from the ISS. The timeline is such that NASA would have between 40 and 80 days to return the stranded crew from the station before the ISS could no longer support the larger compliment. For STS-125's mission to Hubble, a procedure involving EVA crew transfer is being developed. |
kr4mula
Member Posts: 642
From: Cinci, OH
Registered: Mar 2006
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posted 06-13-2007 11:40 AM
quote:
Originally posted by Robert Pearlman:
For STS-125's mission to Hubble, a procedure involving EVA crew transfer is being developed.
Are they going to dredge up the old emergency EVA transfer bags from the early part of the shuttle program? I heard from one of the original shuttle astronauts that used those for a while on ASCANs to test their susceptibility to claustrophobia. Wasn't the issue with a Hubble mission rescue plans that the shuttle wouldn't have enough energy to get from the telescope's orbit into the ISS's? Unless you can do that, an EVA is not going to help. As for the autoland capability, I read some documents in the JSC archives from the 1970s about whether or not they should include a fully automatic landing capability for the shuttle. Both the engineering directorate and mission ops were in favor and there were no technical obstacles - just more software. But the astronaut office was the only one objecting. We see how that turned out. I suspect this was because they didn't want to build themselves out of a job. And that's probably why the manual tasks are essentially simple to execute, almost as if the engineers were forced to offload a few tasks for the astronauts to do. There's also no real reason why the computer can't fly the final approach and landing, either. Cheers, Kevin |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 06-13-2007 11:59 AM
quote:
Originally posted by kr4mula:
Wasn't the issue with a Hubble mission rescue plans that the shuttle wouldn't have enough energy to get from the telescope's orbit into the ISS's? Unless you can do that, an EVA is not going to help.
Indeed, the shuttle cannot move between Hubble and ISS inclinations. The LON plan for STS-125 involves the rescue shuttle rendezvousing with the damaged shuttle, and then conducting a relay of EMU spacewalks between the damaged shuttle and the rescue shuttle. |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 06-13-2007 12:17 PM
quote:
Originally posted by kr4mula:
There's also no real reason why the computer can't fly the final approach and landing, either.
Perhaps true, but you need a crew aboard the shuttle for the mission's activities, especially as the construction of the ISS continues, so there's no reason not to make the crew prime for landing and have the ground/computers assume control only as a back-up. It's also nothing new that the astronaut office would assert their desire to be in control of the vehicle during flight. The same debate was held as early as the Mercury program. |
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