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#3720
by
AnalogMan
on 14 Oct, 2020 19:40
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A near contemporary source document
Chronology of KSC and KSC Related Events for 1979 dated September 22, 1980 has the following entry for the arrival of Enterprise at KSC on April 10, 1979:
[... looking to future events following arrival]
"Pad operations using the Enterprise would include checks of the sound suppression system, flowing the super-cold liquid oxygen and liquid hydrogen propellants, verification tests for the Orbiter Access Arm and Rotating Service Structure, and others. [...]"So if they were not planning to load the External Tank, where were they going to flow cryogenic propellants to/from and why was the shuttle stack needed, or was it just the need for an MLP?
I could not find any other references to this type of test in the Chronology. It can be downloaded here:
https://ntrs.nasa.gov/api/citations/20060017819/downloads/20060017819.pdf
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#3721
by
jbirdav8r
on 15 Oct, 2020 15:41
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I thought this would be a fairly easy and straightforward question to answer but it's turned into an interesting "deep dive."
I found this great paper on lessons learned in external tank development. If you are a fan of the External Tank, it's one of the best resources I've ever seen on the ET.
https://case.edu/cps/sites/case.edu.cps/files/2019-05/2241main_shuttle_et_lesson_021030.pdfPage 18 mentions the GOX vent ice problem, and specifically ties it to the MPTA tests, as I suspected. Another technical paper I came across gives the background to the GOX vent program arising from a problem identified in the "summer of 1979."
Further research indicates that indeed the same tank was used for the ground vibration tests at Marshall and the Enterprise rollout at KSC, the Ground Vibration Test Article (ET-GVTA). This tank was shipped back to Michoud for rebuilding into a flight article, but this never happened. The tank was eventually destroyed in the 2017 Michoud tornado.
I still strongly suspect a true all-up tanking test at the pad never happened until Columbia arrived out there for STS-1, and that the story of Enterprise being tanked and somehow heroically finding this hitherto unknown ice issue is an apocryphal one.
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#3722
by
maia125
on 15 Oct, 2020 18:56
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User Ares67 wrote on a post about Enterprise that they load the LH2 and LOX, but up to the Tail Service Master, since Enterprise didn't have a Main Propulsion System, it couldn't flow the propellant to the External Tank.
This user mentioned a "Orbiter Mid-body umbilicals". Does anybody know what are those?
Once at the pad, Enterprise supported checks of the sound suppression system, as well as loading of the super-cold liquid oxygen and liquid hydrogen propellants. Orbiter mid-body umbilicals were attached to the vehicle. Cryogenic propellants were to flow from storage facilities through the Mobile Launcher Platform into the Tail Service Masts, though these liquefied gases did not go further, for Enterprise lacked the appropriate plumbing.
Verification tests of the Orbiter Access Arm and Rotating Service Structure were conducted. The payload ground-handling mechanism for transfer of an assembled payload from the Rotating Service Structure into the shuttle’s cargo bay also demonstrated its readiness. A 20,000-pound concrete weight, representing a spacecraft, arrived within a sealed canister. With the RSS well away from the shuttle, workers hoisted the canister into the PCR, removed its dummy payload, then rotated the RSS to lie against the back of Enterprise for payload installation within the cargo bay. All this was done under strict environmental control, to prevent contamination of the “spacecraft.”
From May 1 to July 23, 1979, Enterprise completed extensive mechanical fit checks of Kennedy’s checkout and launch operations before she was rolled back to the VAB. “By using Enterprise, we were able to work out a lot of things on a noninterference basis, making the entire effort worthwhile,” Talone said.
https://forum.nasaspaceflight.com/index.php?topic=35828.msg1272680#msg1272680
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#3723
by
DaveS
on 15 Oct, 2020 19:16
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The Orbiter Mid-Body Umbilical Unit (OMBUU) was located on the RSS. It was used to fill/drain the Power Reactant Storage and Distribution (PRSD) storage tanks located below the payload bay. The OMBUU had a large umbilical that connected to an umbilical panel on the orbiter (large green rectangle in photo 2). It was mated during the S0009 Pad Validation operations that took place following rollout. It was demated from the orbiter once servicing of the PRSD had been completed during the launch countdown. Photo 3 shows the midbody umbilical panel on orbiter with the cover removed in the OPF.
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#3724
by
maia125
on 15 Oct, 2020 23:20
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I thought this would be a fairly easy and straightforward question to answer but it's turned into an interesting "deep dive."
When I first read that, I thought: "how did they manage to fill the External Tank?" When you see pictures of Enterprise at LC-39A you can see that there are no umblicals connected to her. I'm glad this doubt has clarified this subject. Thank you all.
The Orbiter Mid-Body Umbilical Unit (OMBUU) was located on the RSS. It was used to fill/drain the Power Reactant Storage and Distribution (PRSD) storage tanks located below the payload bay. The OMBUU had a large umbilical that connected to an umbilical panel on the orbiter (large green rectangle in photo 2). It was mated during the S0009 Pad Validation operations that took place following rollout. It was demated from the orbiter once servicing of the PRSD had been completed during the launch countdown. Photo 3 shows the midbody umbilical panel on orbiter with the cover removed in the OPF.
Thanks, DaveS!
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#3725
by
psloss
on 16 Oct, 2020 00:09
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User Ares67 wrote on a post about Enterprise that they load the LH2 and LOX, but up to the Tail Service Master, since Enterprise didn't have a Main Propulsion System, it couldn't flow the propellant to the External Tank.
NASA KSC did a similar test at Pad 39B late last year to get ready to load propellants on their new vehicle and NASA Stennis did the same in 2018 using turnaround tools as stand-ins.
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#3726
by
maia125
on 16 Oct, 2020 00:15
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So we can assume that's probably what happened when Enterprise was at the pad 39A, right?
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#3727
by
psloss
on 16 Oct, 2020 00:35
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So we can assume that's probably what happened when Enterprise was at the pad 39A, right?
It's plausible, but I'd rather see documentation that's more definitive.
FWIW, an old Shuttle chronology has a nice conflation, attributed to "The HSV-TIMES,07/24/79":
https://ntrs.nasa.gov/citations/19910005807Twelve weeks of ground tests on the lockup orbiter Enterprise ended.
test series was deemed a complete success. Although the ground tests were
successful, a new problem was discovered with the vehicle--there was a
possibility of ice forming on the outside of the fuel tanks, which could
falloff during launch and damage other parts of the ship.
It would be, of course, interesting to read that story from I guess an edition of the Huntsville Times published on 24 July 1979, but it might be involved in this misdemeanor on history.
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#3728
by
woods170
on 16 Oct, 2020 13:43
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I found this great paper on lessons learned in external tank development. If you are a fan of the External Tank, it's one of the best resources I've ever seen on the ET.
https://case.edu/cps/sites/case.edu.cps/files/2019-05/2241main_shuttle_et_lesson_021030.pdf
Page 18 mentions the GOX vent ice problem, and specifically ties it to the MPTA tests, as I suspected. Another technical paper I came across gives the background to the GOX vent program arising from a problem identified in the "summer of 1979."
Excellent find! This specifically ties in the discovery, of the GOX vent ice build-up problem, with the MPTA-ET tests at Stennis.
I still strongly suspect a true all-up tanking test at the pad never happened until Columbia arrived out there for STS-1, and that the story of Enterprise being tanked and somehow heroically finding this hitherto unknown ice issue is an apocryphal one.
You suspect correctly. The first true all-up tanking test at the pad took place with Columbia, prior to the Flight Readiness Firing.
It is reasonable to assume that the incorrect narrative - of tanking tests with Enterprise revealing the GOX vent issue - came into existence because someone added one snippet of information to another snippet of information and drew the wrong conclusion.
The fact that both Enteprise's stint at LC-39A and the discovery of the GOX vent issue (on MPTA-ET) occurred in the (early) summer of 1979 is probably why the wrong conclusions were drawn.
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#3729
by
e of pi
on 07 Nov, 2020 16:54
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Does anyone have any good images of the aft middeck panel that was removed to install or remove the internal airlock on the orbiters? I know I've seen one of the panel off from the cargo bay during processing/overhaul, but I can't find it again at the moment.
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#3730
by
Fequalsma
on 07 Nov, 2020 19:05
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Here are some photos.
F=ma
Edit - should be Xo 576 bulkhead, not 578
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#3731
by
e of pi
on 08 Nov, 2020 14:17
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Thanks, that's exactly what I was thinking of!
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#3732
by
Seamurda
on 08 Nov, 2020 21:28
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Fagets original concept for the fully reusable Shuttle had it entering fully stalled in a near 90 degree angle of attack.
This allowed it to slow down higher in the atmosphere for a lower heat load. This was at the cost of lower cross range.
Was the shuttle as designed capable of entering using this profile and was it considered when the cross range requirement was no longer particularly useful?
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#3733
by
Jorge
on 08 Nov, 2020 21:40
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Fagets original concept for the fully reusable Shuttle had it entering fully stalled in a near 90 degree angle of attack.
This allowed it to slow down higher in the atmosphere for a lower heat load. This was at the cost of lower cross range.
Was the shuttle as designed capable of entering using this profile and was it considered when the cross range requirement was no longer particularly useful?
No and no.
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#3734
by
Fequalsma
on 10 Nov, 2020 00:49
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Does anyone recognize this piece of hardware? I found these in with some Orbiter build photos, but it may not be on the OV?
F=ma
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#3735
by
DaveS
on 10 Nov, 2020 01:31
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That's the Tunnel Adapter Assembly (TAA) that was used to link the orbiter airlock with either Spacelab or SpaceHAB when either of those were flown. Those are some rare photos of the interior of the TAA. Most photos only show the exterior.
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#3736
by
Fequalsma
on 10 Nov, 2020 17:46
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Cool! DaveS can you post an exterior photo of the TAA with this part circled? I'm having a hard time picturing where the large opening at the top is on the TAA. Is it the zig-zag tunnel?
F=ma
That's the Tunnel Adapter Assembly (TAA) that was used to link the orbiter airlock with either Spacelab or SpaceHAB when either of those were flown. Those are some rare photos of the interior of the TAA. Most photos only show the exterior.
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#3737
by
DaveS
on 10 Nov, 2020 17:52
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This is a photo of the TAA in the Bay 1 position for STS-107. Left is forward where it connects to Xo576 bulkhead and right is where it connects to the SpaceHAB Short Transfer Tunnel. The EVA hatch is on the top of the main cylindrical body of the TAA. The TAA is more or less a shortened internal airlock without all the pressurization and EVA support equipment like the Servicing/Cooling Umbilicals (SCUs) used by the EVs before going on to internal suit power and consumables.
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#3738
by
DaveS
on 10 Nov, 2020 18:04
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This screenshot shows STS-106 MS Ed Lu opening the upper EVA hatch to begin the one and only EVA of the mission.
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#3739
by
Fequalsma
on 10 Nov, 2020 20:15
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Thanks DaveS. But where is the part that is in the photos that I posted?
F=ma