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#2160
by
wolfpack
on 16 Aug, 2011 12:23
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The chine areas remained covered with extra black tiles for her entire life, and extra black tiles were added in support of the SILTS experiment on the tail after STS-9. Columbia did replace areas of her LRSI tiles with AFRSI, but the distinctive HRSI chines were never replaced.
But of course the spars and test equipment were the main contributors to her extra weight. Attached an image of Columbia rolling out for STS-107 to shot the tail and chines still covered in HRSI.
And Enterprise's airframe was the same as Columbia's, which is why she was never retrofitted for spaceflight? Same heavier construction?
What did Enterprise lack other than TPS? I assume it had (has) fuel cells, APU's, etc? Was there ever any thought post STS-107 of fitting her out? I'm guessing not.
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#2161
by
arkaska
on 16 Aug, 2011 12:50
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And Enterprise's airframe was the same as Columbia's, which is why she was never retrofitted for spaceflight? Same heavier construction?
What did Enterprise lack other than TPS? I assume it had (has) fuel cells, APU's, etc? Was there ever any thought post STS-107 of fitting her out? I'm guessing not.
The question was raised after the Challenger accident but it was decided it was cheaper to build Endeavour than refit Enterprise
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#2162
by
alk3997
on 16 Aug, 2011 13:01
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And Enterprise's airframe was the same as Columbia's, which is why she was never retrofitted for spaceflight? Same heavier construction?
What did Enterprise lack other than TPS? I assume it had (has) fuel cells, APU's, etc? Was there ever any thought post STS-107 of fitting her out? I'm guessing not.
No, Enterprise (OV-101) was an even earlier airframe than Columbia (OV-102). Columbia's had another year of structures analysis to benefit from prior to construction.
Yes, modernizing OV-101 into a space-rated vehicle was thoroughly looked at prior to the decision to turn the structural test article into Challenger (OV-099). At that point it was found to be easier (time and money) to turn an empty airframe into a real orbiter than to modify Enterprise. The issue was again looked at after the Challenger accident. Again, the answer was that it was cheaper to build Endeavour (OV-105) out of spare parts than it would be to turn Enterprise into an orbital vehicle. The issue was *not* looked at after STS-107 because there were no plans to replace Columbia and OV-101 had sat outside under a essentially a tarp tent for about 10 years at Dulles Airport by that point (now OV-101 is thankfully in a beautiful building).
Again, Enterprise's drawings (engineering drawings) would have been unique to the fleet, even comared with Columbia. Whereas Endeavour's drawings matched that of Discovery (OV-103) and Atlantis (OV-104). Much easier to handle from an analysis standpoint (one analysis fits three of the vehicles). Also, I've heard it said that Enterprise, even in pristine condition, would have cracked in half during entry because the structure was not strong enough in many places. Fixing that would have required more weight and more "uniqueness".
Enterprise is missing most systems (most of the cockpit instrumentation was "donated" to OV-103 for its build). Even the payload bay doors don't work, the thrust structure for the main engines isn't there, there is no fuel cell plumbing, and the list would go on for quite some time. The last photo I have of Enterprise's interior shows that only a mechanical horizon instrument (unique to the ALT flights only) remains in the forward cockpit. The rest is empty spaces where avionics boxes used to be for ALT.
So, bottom line is that Enterprise required lots of work to turn into an orbital vehicle and even if you did all of the work, the result would not have been able to carry as much payload as the sister ships and would have required lots of special analysis because the configuration would have been different than the sister ships.
Andy
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#2163
by
wolfpack
on 16 Aug, 2011 14:16
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And Enterprise's airframe was the same as Columbia's, which is why she was never retrofitted for spaceflight? Same heavier construction?
What did Enterprise lack other than TPS? I assume it had (has) fuel cells, APU's, etc? Was there ever any thought post STS-107 of fitting her out? I'm guessing not.
No, Enterprise (OV-101) was an even earlier airframe than Columbia (OV-102). Columbia's had another year of structures analysis to benefit from prior to construction.
Yes, modernizing OV-101 into a space-rated vehicle was thoroughly looked at prior to the decision to turn the structural test article into Challenger (OV-099). At that point it was found to be easier (time and money) to turn an empty airframe into a real orbiter than to modify Enterprise. The issue was again looked at after the Challenger accident. Again, the answer was that it was cheaper to build Endeavour (OV-105) out of spare parts than it would be to turn Enterprise into an orbital vehicle. The issue was *not* looked at after STS-107 because there were no plans to replace Columbia and OV-101 had sat outside under a essentially a tarp tent for about 10 years at Dulles Airport by that point (now OV-101 is thankfully in a beautiful building).
Again, Enterprise's drawings (engineering drawings) would have been unique to the fleet, even comared with Columbia. Whereas Endeavour's drawings matched that of Discovery (OV-103) and Atlantis (OV-104). Much easier to handle from an analysis standpoint (one analysis fits three of the vehicles). Also, I've heard it said that Enterprise, even in pristine condition, would have cracked in half during entry because the structure was not strong enough in many places. Fixing that would have required more weight and more "uniqueness".
Enterprise is missing most systems (most of the cockpit instrumentation was "donated" to OV-103 for its build). Even the payload bay doors don't work, the thrust structure for the main engines isn't there, there is no fuel cell plumbing, and the list would go on for quite some time. The last photo I have of Enterprise's interior shows that only a mechanical horizon instrument (unique to the ALT flights only) remains in the forward cockpit. The rest is empty spaces where avionics boxes used to be for ALT.
So, bottom line is that Enterprise required lots of work to turn into an orbital vehicle and even if you did all of the work, the result would not have been able to carry as much payload as the sister ships and would have required lots of special analysis because the configuration would have been different than the sister ships.
Andy
Thanks, I was wondering how different it actually was. Sounds like a lot more than TPS! Would love to see flight deck photos, though!
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#2164
by
Specifically-Impulsive
on 16 Aug, 2011 14:40
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#2165
by
sivodave
on 16 Aug, 2011 18:43
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Hi all.
My question for today is: why the POGO suppresion system on the SSME has been installed only on the oxygen feed line and not on the fuel line (or both?). Could this have to do with the fact that oxygen is denser then hydrogen and therefore more capable of dampening the oscillations in flow?
thanks
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#2166
by
Jim
on 16 Aug, 2011 18:54
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Yes and I believe LH2 is not susceptible to pogo
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#2167
by
sivodave
on 16 Aug, 2011 20:29
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Yes and I believe LH2 is not susceptible to pogo
Thanks Jim.
I was also wondering another things: since there are three main engines and since each one of them as its own pogo suppression system, are somehow the three pogo systems connected to each other? I mean, does each pogo suppression system get some kind of feedback from the two other systems so that to regulate its action on the engine? because I suppose the pogo vibrations of the three engines should somehow coupled with each other.
Thanks
Davide
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#2168
by
Wepush
on 16 Aug, 2011 21:06
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There is no feedback and no interaction from one engine's pogo system to another. They operate independently.
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#2169
by
Jim
on 16 Aug, 2011 22:06
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Yes and I believe LH2 is not susceptible to pogo
Thanks Jim.
I was also wondering another things: since there are three main engines and since each one of them as its own pogo suppression system, are somehow the three pogo systems connected to each other? I mean, does each pogo suppression system get some kind of feedback from the two other systems so that to regulate its action on the engine? because I suppose the pogo vibrations of the three engines should somehow coupled with each other.
Thanks
Davide
It isnt an active system. The system is just basically a damper
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#2170
by
DaveS
on 16 Aug, 2011 23:35
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The dots in the boxes on the photo, are they part part of the Space Vision System(SVS)?
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#2171
by
alk3997
on 17 Aug, 2011 05:02
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This is great information. Is there a formal PDF or other type of study document that lists the various problems with making Enterprise space worthy?
Cheers.
I never saw one come across my desk. But most of the work would have been before the Internet was in general use and even before the PC (or TRS-80 for that matter). It may have been studied but I would think it would have been such an obvious answer in the late 1970s and mid-1980s that the detail might not have been required. More likely it was just someone comparing the engineering drawings between OV-101 and noting differences with the later orbiters.
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#2172
by
jeff122670
on 17 Aug, 2011 12:53
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Regarding Columbia, I was under the impression that the black chine areas were actually paint and not tiles. When Columbia arrived at KSC, and rolled over, the chine area wasnt black, however on rollout, it was. I was always told that it was due to engineers thinking that that area might experience more heat and it was treated with a black "paint".
I could be totally wrong, but just something I read somewhere.....
Please correct me if I am wrong.
Thanks!!
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#2173
by
Jim
on 17 Aug, 2011 13:02
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I understand that Columbia was some 8,000 lbs heavier than her sister ships. Exactly where was this extra weight and what was it made up of (ie - airframe, engine mounts, etc)? Did she have extra hardware that the other orbiters did not?
The structure (mostly wings)was made stronger than was needed
And the opposite happened with OV-103 and OV-104, their wings were made too weak and the shuttle had to fly lofted trajectories, which reduced performance. The wings were eventually reinforced and it bought back the performance.
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#2174
by
HelixSpiral
on 17 Aug, 2011 18:12
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Thanks, I was wondering how different it actually was. Sounds like a lot more than TPS! Would love to see flight deck photos, though!
http://www.capcomespace.net/dossiers/espace_US/shuttle/sts/orbiter_avionique.htmThis has comparison photos of OV-101's forward flight deck and the flight orbiters' cockpits. Enterprise's panels are noticibly different.
I can't find an online version, but Jenkins' book has a photo of Enterprise's cockpit from the 1990s gutted of everything.
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#2175
by
alk3997
on 17 Aug, 2011 18:22
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Keep in mind that the photo of "les cockpit de l' Enterprise" shows Enterprise as it no longer exists. I know that when it was turned over to the Smithsonian in the mid-1980s, that cockpit was already gutted (except for the mechanical horizon).
The Enterprise layout was not *that* much different from Columbia's first version. What you are missing are the gauges and switches needed for ascent - hadn't been invented yet. Also the MEDS Phase 1 drawing never existed beyond paper. Only the final MEDS version was actually implemented.
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#2176
by
Specifically-Impulsive
on 18 Aug, 2011 13:26
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[quote author=alk3997 link=topic=17437.msg794430#msg794430
The Enterprise layout was not *that* much different from Columbia's first version. What you are missing are the gauges and switches needed for ascent - hadn't been invented yet. Also the MEDS Phase 1 drawing never existed beyond paper. Only the final MEDS version was actually implemented.
[/quote]
Opinions may vary, but I'd call it significantly different. The GPC status matrix was in front of the pilot instead of CDR, the fuel cell purge controls were on the upper front panel, the left and right overhead panels of switches were completely missing, panel R1 has three steam gauges on it, there is a ?backup? 'artificial horizon' on the fwd panels, most of the steam gauges are missing off the upper front panel....
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#2177
by
STS-85
on 19 Aug, 2011 16:43
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I noticed in a video that on the STS-91 landing, the main gear touchdown, then it rises up again, maybe a foot or two at most, then settles down again..
was this because of certain conditions (wind?) or was there no reason, just happened? Certainly wasn't a major issue, just was curious,, never seen it happen before.
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#2178
by
kch
on 19 Aug, 2011 17:42
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I noticed in a video that on the STS-91 landing, the main gear touchdown, then it rises up again, maybe a foot or two at most, then settles down again..
was this because of certain conditions (wind?) or was there no reason, just happened? Certainly wasn't a major issue, just was curious,, never seen it happen before.
I take it you don't remember this:
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#2179
by
kevin-rf
on 19 Aug, 2011 18:27
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Wasn't that PIO (Pilot Induced Oscillation)?
btw YouTube has a similar video of STS-3
Didn't Prince Charles manage to do something similar on a NASA simulator?
