Author Topic: The "I'm brand new to Shuttle, explain what an RCS thruster is and does etc" Q&A  (Read 20950 times)

Online Chris Bergin

This thread is for people who have either been interested in shuttle, but never took it to the "what's an OMS engine for?" level, or have just gotten into shuttle.

This is literally an opening shuttle education Q&A. The main Shuttle Q&A sections are too involved for newbies I'm starting to hear.

If people want to post basic images and information to help, please do.

We all started somewhere (I used to think the boosters were being supplied by the ET when I was first getting into shuttle, for example!) So let's go basic for this thread.
« Last Edit: 06/27/2009 05:54 am by Chris Bergin »

Offline DansSLK

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OK then i'll give answering that a shot, the RCS (Reaction Control System) consists of 3 modules, 2 located in the OMS pods either side of the vertical tail and 1 on the nose.

The system enables attitude control and maneuvering while on orbit, it is normally active from late in the ascent and is phased out during entry as the aerosurfaces become effective.

The system consists of 44 RCS jets, 38 primary and 6 vernier, the forward RCS has 14 primary and 2 vernier jets, the aft RCS has 12 primary and 2 vernier jets in each pod.

Primary jets provide 870 pounds of thrust and the vernier jets provide 24 pounds of thrust, both types of jet use nitrogen tetroxide as the oxidiser and monomethyl hydrazine as the fuel, the propellants are hypergolic which means they ignite on contact and do not need a seperate ignition system.
« Last Edit: 06/27/2009 06:46 am by DansSLK »

Offline STS Tony

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Now that is funny Dan. Nothing like taking things literally :D

Offline MikeMi.

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Okay, don't know if this question fit to this topic (shouldn't it been postedn in Q&A? :D) but after this 'window damage' and problems with knob I would like to see some scheme of layers of window. Hee I didn't suppose there are at least 3..

Thanks!

Offline DansSLK

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Okay, don't know if this question fit to this topic (shouldn't it been postedn in Q&A? :D) but after this 'window damage' and problems with knob I would like to see some scheme of layers of window. Hee I didn't suppose there are at least 3..

Thanks!

That sounds like something for the other Q&A at a minimum, Chris might want to keep that (drawings) on L2.

Nothing like a bit of British (Welsh!) humor Tony mate, i thought it might get a laugh and be factual at the same time ;), in fact if i put my serious hat on and its cool with Chris if i get some free time to have a sit down i might do a newbie guide to a few other systems, i'm just trying to think what since the orbiter's not exactly learner friendly.

Offline smith5se

Thanks for starting the thread Chris, hopefully there are others who will find it useful as well.  Somewhat of a starting platform for some! (Even if this does point the finger directly at me)

So I was just wondering if someone could put some of the acronyms used around the forum with what they stand for... DansSLK provided a lovely example with the RCS (reaction control system) in the above post.  Sometimes that would make reading posts, knowing what things stood for, a lot easier. (Again sorry, noob to the lingo is all).
« Last Edit: 06/27/2009 05:07 pm by smith5se »
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Offline generic_handle_42

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Thanks for starting the thread Chris, hopefully there are others who will find it useful as well.  Somewhat of a starting platform for some! (Even if this does point the finger directly at me)

So I was just wondering if someone could put some of the acronyms used around the forum with what they stand for... DansSLK provided a lovely example with the RCS (reaction control system) in the above post.  Sometimes that would make reading posts, knowing what things stood for, a lot easier. (Again sorry, noob to the lingo is all).

Actually good question.  This forum has a handy feature that allows you to mouse-over any underlined acronym that you see and it will provide the meaning in a tool-tip.  You need to enable this function though.  Here's how:

1) At the top of the page, click on "Profile"

2) On the left of the profile page, click on "Look and Layout"

3) Check the top check-box that says "Highlight items from Acronyms List"

4) Click "Change Profile"

You will now notice many acronyms are underlined and you can see what they mean.  If an acronym is not underlined, it has not been defined on our acronyms page. (Top of the forum, click on "Acronyms").
-Nick-

Offline smith5se

Thanks for pointing that out, that helps a lot!
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Offline Sesquipedalian

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The system enables attitude control
Ahh, so it's for stress relief!  That explains why every astronaut you meet is so friendly. :D

(This is a newbie thread, so maybe people shouldn't assume everyone knows the definitions. ;)  For instance, I had to look up "vernier".  I assumed from the context that it was a fancy way of saying "secondary", but I discovered it's more nuanced than that -- it's actually more like the coarse and fine adjustments on a microscope.)

Offline smith5se

So another question comes to mind, if it doesn't belong in here feel free to move it, well ok more than one...

1) What is the square footage avaliable for living space once the shuttle has been packed with the required equipment and supplies?

2) Why the changes in crew sizes, from 4 up to 7, even 8 (once right?); and the current set up for seating is 4 on flight deck and the rest on mid-deck? (if I understand correctly) And a run off question, during spacewalks, you have two out, one operating the arm, and commander at work; what is everyone else's function?

3) Does anyone have any book suggestions for reading, school is done for a bit and I can actully do leisure reading... go figure!

Ah well... at least I've come out of my I don't know much noob bubble...


Thanks for answering in advance...
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Offline Antares

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3) http://forum.nasaspaceflight.com/index.php?topic=15532.0  You'll find a great many ideas there.  My personal favorites are Angle of Attack, The Man Who Ran the Moon, Stages to Saturn if you like rocket design, Rocket Propulsion Elements if you like engine design, Fundamentals of Astrodynamics if you like orbital mechanics.
If I like something on NSF, it's probably because I know it to be accurate.  Every once in a while, it's just something I agree with.  Facts generally receive the former.

Offline Jim

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So another question comes to mind, if it doesn't belong in here feel free to move it, well ok more than one...

1) What is the square footage avaliable for living space once the shuttle has been packed with the required equipment and supplies?

2) Why the changes in crew sizes, from 4 up to 7, even 8 (once right?); and the current set up for seating is 4 on flight deck and the rest on mid-deck? (if I understand correctly)

3 And a run off question, during spacewalks, you have two out, one operating the arm, and commander at work; what is everyone else's function?


1.  It varies since the middeck is reconfigured on orbit.  Most of the seats are removed and other hardware moved around.  Also square footage is basically meaningless in zero g, the 3rd dimension is now more useable.

2.  5 crew became the standard, once SAS was understood.  The numbers vary based on mission requirements like: ISS crew rotation, Spacelab/Spacehab module missions that may have around the clock ops, spacewalk intensive missions like ISS construction and HST servicing which require 4 spacewalkers who alternate days, etc

3.  the 5th is following the timeline and making sure that all the tasks get done.  The remaining maybe doing experiments or getting ready for another spacewalk.

Offline smith5se

So to correct myself I that, should I have asked cubic feet? (sorry lost on that concept)

@antares, thanks for the suggestions, I'll have to check a few of them out.
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Offline Lab Lemming

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Why is the ET tank foam brown?  Is the color in the gas (e.g. NO2), or the plastic?

Offline Jim

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Why is the ET tank foam brown?  Is the color in the gas (e.g. NO2), or the plastic?

UV rays darken it

Offline Jorge

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Why is the ET tank foam brown?  Is the color in the gas (e.g. NO2), or the plastic?

UV rays darken it

Right. Look at a photo of an ET coming straight out of Michoud, and the foam will be a light pink color.
JRF

Offline AnalogMan

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Why is the ET tank foam brown?  Is the color in the gas (e.g. NO2), or the plastic?

UV rays darken it

Right. Look at a photo of an ET coming straight out of Michoud, and the foam will be a light pink color.

Here's one of ET-132 arriving at the VAB for the STS-128 mission.

Offline smith5se

On the ET notes, can someone explain why the color of the ET tank changed from white to orange? Was is just so the foam was more visible for spotting, or is there more to it?
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Offline Lee Jay

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On the ET notes, can someone explain why the color of the ET tank changed from white to orange? Was is just so the foam was more visible for spotting, or is there more to it?

The first ETs were covered with a coating (FRL = flame retardant latex, IIRC) that made them white.  Soon, the coating was dropped as unnecessary and dropping it saved some weight.

Offline Jorge

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On the ET notes, can someone explain why the color of the ET tank changed from white to orange? Was is just so the foam was more visible for spotting, or is there more to it?

The first two ETs were painted white to minimize exposure to the elements, since the tanks were (correctly) anticipated to have long pad stays.

The paint added several hundred pounds of weight to the ET so NASA stopped painting them as soon as they figured it was no longer necessary.

Answering the obvious followup question in advance: there would be no point in starting to paint the ETs white again to keep foam from falling off the tank. Postflight data showed STS-1 and 2 had about as many debris impacts as subsequent flights with unpainted tanks.
JRF

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