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#1740
by
JayP
on 10 Mar, 2011 00:17
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Only 39 out of 100 possible is sadder than I thought. Still at the top of her game, as they keep saying.
But if they had made the originaly projected flight rate, she would have probably hit 100 missions by now. Anyway you look at it, she had a remarkable and complete career.
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#1741
by
kraisee
on 10 Mar, 2011 03:35
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When they were being designed, the original 'life' of an orbiter was expected to be less than 10 years (having flown 100 times in less than that timeframe)..
The B-52 has been flying longer than that, but it has needed re-certifying a few times now in its history, again because of its age.
Although they haven't flown as often as originally foreseen, and are still in great condition, the three remaining orbiter's airframes are still quite a bit older than the design was originally intended to last (Discovery was fast approaching 3 times its original design intent). So the same basic re-certification is just needed for the Orbiter fleet, purely because of their age. CAIB were simply bringing this need to NASA's attention, if they wanted to use Shuttle much beyond 2010.
Ross.
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#1742
by
elmarko
on 10 Mar, 2011 12:02
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Can somebody please tell me when TAL aborts were first developed/invented for use? I seem to remember they weren't an option for every single flight (as in, they weren't there from STS-1), and for some reason I'm seeing "STS-8" and "Joe Engle" in my head, I remember reading about an astronaut, could have been him, developing it in a simulator and then they did more work on it and it became an official option.
Am I pulling this out of my bum, or did it actually happen?
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#1743
by
Jim
on 10 Mar, 2011 13:01
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Can somebody please tell me when TAL aborts were first developed/invented for use? I seem to remember they weren't an option for every single flight (as in, they weren't there from STS-1), and for some reason I'm seeing "STS-8" and "Joe Engle" in my head, I remember reading about an astronaut, could have been him, developing it in a simulator and then they did more work on it and it became an official option.
Am I pulling this out of my bum, or did it actually happen?
They were available STS-2
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#1744
by
Namechange User
on 10 Mar, 2011 13:13
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When they were being designed, the original 'life' of an orbiter was expected to be less than 10 years (having flown 100 times in less than that timeframe)..
The B-52 has been flying longer than that, but it has needed re-certifying a few times now in its history, again because of its age.
Although they haven't flown as often as originally foreseen, and are still in great condition, the three remaining orbiter's airframes are still quite a bit older than the design was originally intended to last (Discovery was fast approaching 3 times its original design intent). So the same basic re-certification is just needed for the Orbiter fleet, purely because of their age. CAIB were simply bringing this need to NASA's attention, if they wanted to use Shuttle much beyond 2010.
Ross.
Well that's not exactly correct. The original certs, the paperwork, stated 100 missions or 10 years, whichever came first. The time limit was really just a line pulled from the air. The specific systems, etc were not designed to go belly up and expire at 10 years plus one day.
Eventually, and long before the loss of Columbia, we had essentially removed most of the "10 year" comments from the certifications.
During RTF, we had a program known as "Mid-Life Certification Review". This was in work prior to the release of the CAIB report. It's intent was to verify, after these number of years, that the systems and components are "flown like we tested" and if not what should be done to "test and/or analyze like we fly".
The spreadsheets and specific things we looked at were rather intense. There were a few "pokeouts" where we performed some limited testing here or there and/or analysis to update some certifications. The good news is nothing major was found.
This "recertification" today is complete and given the cert testing performed initially, the rigor we have placed in the review process and other certs done over the years, the maintenance performed, the inspection history, etc I'm confident the fleet is in great shape and certainly capable of flying some more beyond the current NASA manifest.
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#1745
by
elmarko
on 10 Mar, 2011 13:23
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Can somebody please tell me when TAL aborts were first developed/invented for use? I seem to remember they weren't an option for every single flight (as in, they weren't there from STS-1), and for some reason I'm seeing "STS-8" and "Joe Engle" in my head, I remember reading about an astronaut, could have been him, developing it in a simulator and then they did more work on it and it became an official option.
Am I pulling this out of my bum, or did it actually happen?
They were available STS-2
Thanks Jim. Was I right with my story about it being developed in the sim by one of the crew, though? Any ideas who?
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#1746
by
psloss
on 10 Mar, 2011 13:56
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Can somebody please tell me when TAL aborts were first developed/invented for use? I seem to remember they weren't an option for every single flight (as in, they weren't there from STS-1), and for some reason I'm seeing "STS-8" and "Joe Engle" in my head, I remember reading about an astronaut, could have been him, developing it in a simulator and then they did more work on it and it became an official option.
Am I pulling this out of my bum, or did it actually happen?
They were available STS-2
Thanks Jim. Was I right with my story about it being developed in the sim by one of the crew, though? Any ideas who?
IIRC, I read somewhere that the STS-2 crew worked on the "abort to Rota" prior to STS-1; however, it wasn't a certified abort mode at that point.
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#1747
by
elmarko
on 10 Mar, 2011 14:37
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That's what I remember reading too.
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#1748
by
Malderi
on 10 Mar, 2011 15:30
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Since I believe there are parts of ascent where the only abort option is TAL, what would have been done if an engine failed during that time on STS-1? Would they have been within the ejection seat envelope at that time?
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#1749
by
iskyfly
on 10 Mar, 2011 15:32
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During Discovery's STS-133 return the following was radioed up to the crew;
"9% adjust on the speed brake"
what does that mean?
Also, I'm probably imagining things, but did the pitch angle of the orbiter at touchdown seem higher than previous landings?
Thanks
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#1750
by
Namechange User
on 10 Mar, 2011 15:35
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During Discovery's STS-133 return the following was radioed up to the crew;
"9% adjust on the speed brake"
what does that mean?
Also, I'm probably imagining things, but did the pitch angle of the orbiter at touchdown seem higher than previous landings?
Thanks
The speed brake is the "fins" that come out of the vertical stabilizer.
Pitch angle was normal.
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#1751
by
Jim
on 10 Mar, 2011 17:55
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Since I believe there are parts of ascent where the only abort option is TAL, what would have been done if an engine failed during that time on STS-1? Would they have been within the ejection seat envelope at that time?
STS-1 was shaped to work without TAL.
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#1752
by
Malderi
on 10 Mar, 2011 18:01
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Thanks, Jim. Just to clarify: does that mean that after STS-1 it was expected that TAL would be a certified abort mode, so it was designed as a unique ascent trajectory? Or was the STS-1 ascent supposed to be the "normal" one, but instead things were changed to allow TAL aborts? Just trying to get the historical perspective on what was planned and when things changed.
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#1753
by
iskyfly
on 10 Mar, 2011 18:57
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The speed brake is the "fins" that come out of the vertical stabilizer.
yes, yes.. that i know... and i understand what the values mean when MCC says "spreadbreak 15%. However, this is the first time ive heard the term "x% adjust on the speedbreak" in the same call up.
that is what im asking about....
thanks!
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#1754
by
ksc_houston
on 10 Mar, 2011 19:16
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Question:
I saw a couple of years ago an article about Atlantis that said her retirement should be urged, because of a problem with her aging tanks(cryo tanks?). Can someone clarify that for me?
Thanks
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#1755
by
Namechange User
on 10 Mar, 2011 19:17
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The speed brake is the "fins" that come out of the vertical stabilizer.
yes, yes.. that i know... and i understand what the values mean when MCC says "spreadbreak 15%. However, this is the first time ive heard the term "x% adjust on the speedbreak" in the same call up.
that is what im asking about....
thanks!
It's a call to set the speed break to that percent open.
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#1756
by
Namechange User
on 10 Mar, 2011 19:19
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Question:
I saw a couple of years ago an article about Atlantis that said her retirement should be urged, because of a problem with her aging tanks(cryo tanks?). Can someone clarify that for me?
Thanks
No idea since it is not accurate. May have been the press reacting in a typical fashion to something we were studying with the COPVs. That concern has been addressed and is no longer a factor.
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#1757
by
Jim
on 10 Mar, 2011 19:33
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Thanks, Jim. Just to clarify: does that mean that after STS-1 it was expected that TAL would be a certified abort mode, so it was designed as a unique ascent trajectory? Or was the STS-1 ascent supposed to be the "normal" one, but instead things were changed to allow TAL aborts? Just trying to get the historical perspective on what was planned and when things changed.
TAL was added to increase performance by covering a "black zone"
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#1758
by
Malderi
on 10 Mar, 2011 19:51
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Gotcha. Thanks again, Jim.
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#1759
by
ChrisGebhardt
on 10 Mar, 2011 20:36
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Question:
I saw a couple of years ago an article about Atlantis that said her retirement should be urged, because of a problem with her aging tanks(cryo tanks?). Can someone clarify that for me?
Thanks
I remember what you're talking about. They were helium tanks that were old, and spares were not available. One analysis found that they would burst before they leaked, which would be catastrophic. Another analysis found that they would leak before they burst. That's all I remember.
Additionally, the tanks are now pressurized in a stepped fashion to 80% and than up to 100%.