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#3340
by
yatpay
on 25 Feb, 2015 19:08
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Was there ever an EVA to the rear of the orbiter? No real reason for asking, just curious if it ever came up and why.
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#3341
by
Proponent
on 26 Feb, 2015 14:27
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1)Approx. how much extra payload mass would 25,000lbs decrease in booster weight allow for?
There's typically an exchange ratio between booster-stage weight reduction and LEO payload gain of very roughly ten. You could plug some numbers into
John Schilling's Launch Vehicle Performance Calculator to get a more accurate estimate.
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#3342
by
Jim
on 26 Feb, 2015 14:32
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Was there ever an EVA to the rear of the orbiter? No real reason to asking, just curious if it ever came up and why.
No
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#3343
by
Ronpur50
on 26 Feb, 2015 19:23
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Anyone remember when NASA made the decision to change the back stripe on the edge of the Shuttle wings to white squares?
Was it done after their long maintenance periods? Also, why the transition from black to white? Was it for looks or did it serve a specific function?
MikeEndeavor23
Are you asking about the black wing chines seen only on Columbia?
If so, do a search here for "Columbia wing chines". It has been discussed a lot. This is the best answer I remember:
http://forum.nasaspaceflight.com/index.php?topic=17437.msg860524#msg860524
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#3344
by
psloss
on 26 Feb, 2015 20:52
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Anyone remember when NASA made the decision to change the back stripe on the edge of the Shuttle wings to white squares?
Was it done after their long maintenance periods? Also, why the transition from black to white? Was it for looks or did it serve a specific function?
MikeEndeavor23
Are you asking about the black wing chines seen only on Columbia?
If so, do a search here for "Columbia wing chines". It has been discussed a lot. This is the best answer I remember:
http://forum.nasaspaceflight.com/index.php?topic=17437.msg860524#msg860524
The question was vague...another wild guess that might, possibly, maybe sorta fit "back stripe" and "white squares" is the change to the elevon flipper doors. Screen of a STS-109 FRR slide attached (that being the first flight for Columbia after her last OMDP), which notes the material change and TPS change. I believe this was one of the "orbiter diet" parts of the Performance Enhancement "program" for a 51.6-degree inclined ISS.
Reference for the first screenshot:
http://www.jsc.nasa.gov/news/columbia/frr/sts-109/11_vehiclebu.pdfAdded a slide from "Proceedings of Symposium Commemorating the Space Shuttle Program" held at Georgia Tech in June 2011:
http://www.ae.gatech.edu/sites/default/files/pdf_files/ProceedingsWEBred.pdf
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#3345
by
Ronpur50
on 26 Feb, 2015 23:52
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That last slide explains several changes to the TPS I have noticed while researching for models. I often wondered why the blankets had a smaller area on the wing on later flights.
And yes, your answer fits the question better.
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#3346
by
MikeEndeavor23
on 03 Mar, 2015 04:12
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Hi everyone!
Thanks for the answer to my "black stripe" vers "white tiles" question. I guess it was indeed the change to the flipper doors. Although I really had no idea that they were called "flipper doors."
This leads to the question of what "flipper doors" were for....
MikeEndeavor23
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#3347
by
SWGlassPit
on 03 Mar, 2015 14:08
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Jim will probably chime in and correct me if I'm wrong, but I believe they served to cover the elevon hinges.
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#3348
by
joema
on 03 Mar, 2015 20:00
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Was there ever an EVA to the rear of the orbiter? No real reason for asking, just curious if it ever came up and why.
There was never one in actuality but every flight was prepared for a contingency EVA procedure to manually close the umbilical propellant doors beneath the orbiter aft end. If these somehow failed to close or the talkback indicator indicated they weren't latched, this would be critical during reentry.
There was specific ground hardware called the ET Door Trainer so crews could practice the procedure. They may have carried a tool to assist with this possibility -- I don't remember.
Obviously this was considered a low probability event, but not so low it was not considered or practiced. Since there was no easy way to get there, I think the procedure involved some makeshift methods such as throwing a laundry bag with a rope over the elevons. I'm sure someone will correct me if wrong.
This issue came up during the Columbia Accident Investigation. During the mission some felt an EVA to the payload bay to look at the wing leading edge was too risky, yet each flight had trained crew prepared for the much higher risk EVA underneath the orbiter aft end.
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#3349
by
brahmanknight
on 05 Mar, 2015 15:44
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When SSMEs were replaced on the launch pad, was there a complete enclosure to protect the process from the elements, or was it open?
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#3350
by
psloss
on 05 Mar, 2015 19:10
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When SSMEs were replaced on the launch pad, was there a complete enclosure to protect the process from the elements, or was it open?
It was (more or less) open -- similar to the component replacement on one of the engines at the pad during the last launch campaign.
(For something more extraordinary, there was the time a rudder/speed brake PDU was replaced at the pad.)
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#3351
by
DaveS
on 05 Mar, 2015 19:26
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#3352
by
the_other_Doug
on 06 Mar, 2015 00:44
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Hmmm... I always thought that the Shuttle engines were pulled off an orbiter after a mission (as were the OMS pods), and taken off to be refurbished. Since the engines usually took longer to go through their refurbishment process than the orbiter itself, it was common to see a different set of three engines re-installed onto the orbiter (though the OMS pods usually stayed with the same vehicles). The engines, as I understood it, ended up flying on all of the orbiters at one time or another, right?
That said, when did they ever replace engines while the Shuttle was on the pad? Didn't they normally only do that in the OPF?
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#3353
by
psloss
on 06 Mar, 2015 01:21
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Hmmm... I always thought that the Shuttle engines were pulled off an orbiter after a mission (as were the OMS pods), and taken off to be refurbished.
That was the norm. Issues would come up occasionally when Shuttle vehicles were out at the pad or in the VAB. (IIRC, the engines were temporarily removed from the STS-117 vehicle in the VAB while the tank was getting all those hail repairs...
link.)
That said, when did they ever replace engines while the Shuttle was on the pad?
Less and less over the time the program was flying...an obvious one would be STS-6 due to all the issues discovered around the two FRFs (there are some pictures in a historical thread starting around
here; not sure when the last occurrence was but as an example the engines for the STS-49 vehicle were replaced at the pad after Endeavour's FRF.
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#3354
by
iskyfly
on 11 Mar, 2015 11:52
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Some questions regarding the sims (specifically launch & entry).
Did the sims have the same GPC's and BFS that the orbiters had or were their functions simulated?
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#3355
by
wolfpack
on 11 Mar, 2015 12:40
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Some questions regarding the sims (specifically launch & entry).
Did the sims have the same GPC's and BFS that the orbiters had or were their functions simulated?
SAIL would have had everything the same. Not sure about the motion based simulator.
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#3356
by
Malderi
on 11 Mar, 2015 20:57
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Some questions regarding the sims (specifically launch & entry).
Did the sims have the same GPC's and BFS that the orbiters had or were their functions simulated?
SAIL would have had everything the same. Not sure about the motion based simulator.
Motion base had GPCs and BFS running flight software, and indeed some software problems were occasionally found in that way (a few that required certain types of astronaut action, primarily.) I don't know exact details of these, but I know a few were found during training sims.
Edit: I believe the GPCs in the motion base were engineering units and not flight units, but the software was unmodified as I recall (full redundant set etc). I may be wrong about that though.
Not sure about the fixed base sim. SAIL definitely did (as avionics integration was the entire point of SAIL). There were more Shuttle "cockpits" at JSC than many recognized, I attempted to count once and arrived at around a dozen. FBS, MBS, SAIL, 4 SSTs, JAEL, FFT, 2 front cabins in Building 9 SVMF that I forget the name of (neither they nor FFT had any avionics)... probably forgetting a few.
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#3357
by
alk3997
on 12 Mar, 2015 14:14
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From a Shuttle flight software testing standpoint, the most used simulator hasn't been mentioned. That was the SPF with teh Flight Equipment Interface Devices (FEIDs). Each FEID had up to 3 flight-level GPCs. I think there were 5 FEIDs. This was the primary testing facility for development of flight software. It was usually only after the flight software was released that the software would be tested in SAIL and before flights.
SAIL (OV-095), of course, had 5 GPCs with the exact same length of wiring as the flight orbiters.
SMS used SIDs which had 5 flight-like GPCs for each of the three bases. They had to have 5 GPCs since many of the sim training sessions involved practicing GPC failure scenarios.
I believe KSC had real GPCs for payload testing in their facility (I'm trying to remember the name of the testing lab).
As time marched on, more simulations appeared but many of those didn't use actual flight software.
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#3358
by
Hoonte
on 17 Mar, 2015 21:15
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Can anyone tell me where the ''big hole'' is for? Cables?
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#3359
by
psloss
on 17 Mar, 2015 21:26
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Can anyone tell me where the ''big hole'' is for? Cables?
That's where the star trackers were.
