Author Topic: Shuttle Questions Q and A (2)  (Read 195283 times)

Offline GLS

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Re: Shuttle Questions Q and A (2)
« Reply #120 on: 06/02/2006 02:23 pm »
The second cylinder from the top on the LH SRM on (at least) STS-4, STS-5, STS-6 and STS-27R, has "something" on the outside. http://images.jsc.nasa.gov/lores/S82-39537.jpg What's that?

And while we're talking about SRBs, does anyone know why the SRBs, on the OV-104 stack that rolled to the pad in October 86 (and the SRB only stack rollout in the summer of 86) http://www.capcomespace.net/dossiers/espace_US/shuttle/1986-95/1986%20octobre%20atlantis%2001.jpg , have the field joints painted black and the factory joints painted white? (all the other SRBs have, or just the factory joints painted black or all joints white)
GLS is go for main engine start!

Offline shuttlefan

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Re: Shuttle Questions Q and A (2)
« Reply #121 on: 06/05/2006 02:22 am »
After which Shuttle Mission did they stop performing tanking tests of the ET as a standard pad-flow milestone? I believe these were also called WCCDTs ( wet countdown demonstration tests ), and did they all end at T-31 seconds? :)  :)

Offline GLS

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Re: Shuttle Questions Q and A (2)
« Reply #122 on: 06/05/2006 10:56 am »
They did the WCDT on STS-1, 2, 3 and 4. STS-5 had a Integrated tanking "something" (I'll have to search the name...). STS-26R had a WCDT before the FRF.

Other tankings (that I'm aware) were 2 tankings on STS-35 due to the LH2 leaks, 4 on STS-38 also due to LH2 leaks, 1 on STS-91 to check the new SLWT and the 2 tankings on STS-114. Not sure but I think the STS-35 and 38 tankings were "mini-tanking" tests, were you don't fill the all the tank. Give me a couple days to search my stuff and I'll have more info....


BTW, anyone wants to take my SRB question?
GLS is go for main engine start!

Offline shuttlefan

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Re: Shuttle Questions Q and A (2)
« Reply #123 on: 06/06/2006 01:06 am »
I thought I read they performed tanking tests even upto and including STS-9-I may be wrong. :)

Offline GLS

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Re: Shuttle Questions Q and A (2)
« Reply #124 on: 06/08/2006 10:38 am »
WCDT were performed on STS-1, 2, 3, 4 and 26R. On STS-1 the WCDT ended in the FRF at 200281, while on STS-26R the WCDT was on 010888 and the FRF was to be on 040888 but was delayed to 100888. STS-5 had a Integrated Cryogenic Loading Test to verify ET SOFI integrity, verify the loading sequence and test the ability of vehicle components to function properly in the supercold environment. STS-1 also had 3 tankings: the first loading test on 220181, and 2 tankings on 250381 and 270381 to check the repaired ET SOFI that fell off (if you look at FRF pictures/video you'll see that the ET is wraped in the area below the orbiter nose).
Then came the hot summer of 1990 (or cold due to all the leaking LH2 :) ): 2 mini-tankings on STS-35, the first on 060690 with LH2 loaded to 20%, and the second on 301090 with LH2 loaded to 100% with normal topping and stable replenish. 4 mini-tankings on STS-38, on 290690 with 5% LH2, on 130790 with 50-65% LH2, on 250790 with 10-15%, and on 241090 with 25% LH2. Then they did something on STS-37, an inert leak check or something. I think it had to do with having OV-104 and ET-37 together again (ET-37 was the original tank on STS-38, it did the first 3 mini-tankings).
STS-91 had a tanking test on 180598 to test the first SLWT, and STS-114 had 2, on 140405 and on 200505. Is this enough info for you?

"I thought I read they performed tanking tests even upto and including STS-9-I may be wrong."
Don't know because on the web, NASA has (in my opinion) little info about the early missions...., but I think the WCDTs were only a part of OFT missions.
GLS is go for main engine start!

Offline shuttlefan

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Re: Shuttle Questions Q and A (2)
« Reply #125 on: 06/08/2006 01:59 pm »
Thank-you so kindly for the detailed answer!!! :)  :)

Offline shuttlefan

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RE: Shuttle Questions Q and A (2)
« Reply #126 on: 06/09/2006 04:00 am »
Would it be possible for NASA to ignite the OMS engines on the pad and let them run for 20 seconds just like they did with the SSMEs several times in earlier shuttle years, though I do realize there is no test objective that would require this... :)

Offline Jim

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Re: Shuttle Questions Q and A (2)
« Reply #127 on: 06/09/2006 04:13 am »
Anything is possible, but there has to be a reason.    It was designed to.

Offline GLS

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RE: Shuttle Questions Q and A (2)
« Reply #128 on: 06/09/2006 01:27 pm »
I don't think the OMS engines can be fired at sea level, just above 70000 ft or so....
GLS is go for main engine start!

Offline mkirk

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RE: Shuttle Questions Q and A (2)
« Reply #129 on: 06/10/2006 12:15 am »
Quote
shuttlefan - 8/6/2006  10:47 PM

Would it be possible for NASA to ignite the OMS engines on the pad and let them run for 20 seconds just like they did with the SSMEs several times in earlier shuttle years, though I do realize there is no test objective that would require this... :)

GLS’ post is correct there is an altitude restriction for the OMS (orbital maneuvering system) engines.  They are not ignited below 70,000 feet primarily because of aero-thermal concerns.  The worry is that the engine bells would collapse.

I don’t believe there is any altitude constraint for the RCS (reaction control system) jets.  However, the first time they are used is right at SRB SEP (solid rocket booster separation) to help protect the orbiter windows from debris/residue by deflecting the plume produced by the separation motors.  The last time they are used during a mission is when the orbiter slows below MACH 1 (which is ususally at 50,000 to 55,000 feet) prior to landing.

Interestingly, with regard to Pad test firings, the RCS thrusters on the Gemini capsule were test fired late in the countdown after the crew had been strapped into their seats and the service structure had been retracted.

Mark Kirkman
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Offline shuttlefan

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RE: Shuttle Questions Q and A (2)
« Reply #130 on: 06/11/2006 06:56 pm »
How thick is the steel that the outside of the SRBs are made of and how many holes are there around the bottoms and tops of the segments, the holes that the technicians insert bolts through when the segments are stacked together?

Offline Justin Space

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RE: Shuttle Questions Q and A (2)
« Reply #131 on: 06/12/2006 04:11 pm »
How long does it take for the exhaust to clear the pad after launch? Is that cloudof smoke hazardous?

Offline Chris Bergin

RE: Shuttle Questions Q and A (2)
« Reply #132 on: 06/12/2006 06:20 pm »
Quote
Justin Space - 12/6/2006  4:58 PM

How long does it take for the exhaust to clear the pad after launch? Is that cloudof smoke hazardous?

I believe there is hazardous gas involved and it takes three days for it to be safe. Someone will be able to confirm that.

Offline mkirk

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RE: Shuttle Questions Q and A (2)
« Reply #133 on: 06/12/2006 07:46 pm »
Winds out at the Pad obviously play a major role in how long it takes for the exhaust cloud to disperse.  It typically goes away pretty quickly.  There is a very distinct oder after launch...probably not in my best interest to be inhaling that very deeply. ;)

Pad access after launch is controlled by the NASA Test Director.  About 10 minutes after launch the initial Pad Safing Teams are dispatched.  The areas around the Pad are inspected and within about an hour the FSS and MLP are inspected.  FOD (foreign object debris) walk downs are conducted and by about 3 hours 15 minutes after Launch the Pad is declared open.

In fact they usually let the Media/Photographers in the Pad area within hours of Launch so they can retrieve their remote cameras.

My theory on that is NASA is letting those guys (photographers) serve as human “canaries” like they use in coal mines.  If a photographer keels over then the NASA Test Director knows it is not safe to let people he likes into the Pad area. :)

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Offline Launch Fan

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RE: Shuttle Questions Q and A (2)
« Reply #134 on: 06/12/2006 09:52 pm »
Quote
mkirk - 12/6/2006  2:33 PM


My theory on that is NASA is letting those guys (photographers) serve as human “canaries” like they use in coal mines.  If a photographer keels over then the NASA Test Director knows it is not safe to let people he likes into the Pad area. :)


Classic!

Offline astrobrian

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Re: Shuttle Questions Q and A (2)
« Reply #135 on: 06/12/2006 10:19 pm »
So wrong yet so funny.  
If I remember correctly the stuff is very acidic too

Offline mkirk

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Re: Shuttle Questions Q and A (2)
« Reply #136 on: 06/12/2006 10:29 pm »
Quote
Launch Fan - 12/6/2006  4:39 PM

Quote
mkirk - 12/6/2006  2:33 PM


My theory on that is NASA is letting those guys (photographers) serve as human “canaries” like they use in coal mines.  If a photographer keels over then the NASA Test Director knows it is not safe to let people he likes into the Pad area. :)


Classic!

Quote
astrobrian - 12/6/2006  5:06 PM

So wrong yet so funny.  
If I remember correctly the stuff is very acidic too

I guess I should point out that as part of my cosulting work I am one of those photographers/canaries...as is Ben

Mark Kirkman
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Offline astrobrian

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Re: Shuttle Questions Q and A (2)
« Reply #137 on: 06/12/2006 10:41 pm »
Still wrong, maybe not as funny now :) You described it in a way that was more from an outsider perspective rather than one who does that stuff first hand

Offline Rocket Guy

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Re: Shuttle Questions Q and A (2)
« Reply #138 on: 06/12/2006 10:51 pm »
Not only are we out there, but we touch that exhaust with our bare hands. It's hazardous but certainly not on the order of keeping people out very long. It's all dilluted a lot.

SRB exhaust consists mainly of of hydrohcholic acid (very corrosive to things like cameras (!), in liquid (dissolved in water) and gas forms); aluminum oxide (white residue that gets all over everything); and nitrogen dioxide (the smelly gas in the air, toxic in concentrated amounts). There's more stuff (because the fuel has polymers as well keeping it together) but that is what results from the burning of the fuel portion.

Offline astrobrian

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Re: Shuttle Questions Q and A (2)
« Reply #139 on: 06/12/2006 10:52 pm »
ok, so then is it in concentrated amounts by the time you go out there or is it seriously up in the air , no pun intended, if the air is breathable? I wouldn't think NASA would risk people just to get the film back to the truck a few minutes sooner. I would guess NASA has hazardous gas detection machines of some kind for you guys

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