Author Topic: Shuttle Questions Q & A (Part 3)  (Read 308103 times)

Offline nathan.moeller

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Re: Shuttle Questions Q & A (Part 3)
« Reply #40 on: 01/21/2007 04:55 AM »
Great Mark!  That's the funniest thing I read all day. :) Let's get someone to run those numbers and see what they come up with!
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Offline elmarko

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Re: Shuttle Questions Q & A (Part 3)
« Reply #41 on: 01/21/2007 12:38 PM »
I would be interested in that! I'm also tempted to run a sim in Orbiter too :P

To clarify the rules, are we going for the highest circularised orbit, or can we just shoot upwards at 90deg pitch and burn out every propellant available? :p

Offline Argosy

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Re: Shuttle Questions Q & A (Part 3)
« Reply #42 on: 01/21/2007 12:40 PM »
How about storing some extra fuel in the cargo bay(that would be burned also)? BTW, I do realize that the would not be able to return to earth, it's just a question. And who says they have to return to the earth? I never said that :-)...

Offline Jim

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Re: Shuttle Questions Q & A (Part 3)
« Reply #43 on: 01/21/2007 01:19 PM »
Quote
Argosy - 21/1/2007  8:40 AM

How about storing some extra fuel in the cargo bay(that would be burned also)?

Now you are including things that don't exist.  How about adding two more SRB's or a 4th SSME?

I know want you are getting at, there is now way the shuttle can leave LEO

Offline nathan.moeller

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Re: Shuttle Questions Q & A (Part 3)
« Reply #44 on: 01/21/2007 01:43 PM »
Hey Jim.  That reminds me of another question.  Including those currently installed on the orbiters, how many useable SSMEs are currently in existence?
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Offline Jim

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Re: Shuttle Questions Q & A (Part 3)
« Reply #45 on: 01/21/2007 01:48 PM »
Quote
nathan.moeller - 21/1/2007  9:43 AM

Hey Jim.  That reminds me of another question.  Including those currently installed on the orbiters, how many useable SSMEs are currently in existence?

there is a list on L2

Offline mainengine

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Re: Shuttle Questions Q & A (Part 3)
« Reply #46 on: 01/21/2007 01:59 PM »
There are 12 Block-2-engines in use.
Newest one is SSME 2059 flying on STS-117 in March.
A stock of 15 engines was originally planned.

You may have a look at http://www.mainengine.gratis-webspace.de/ssme_gen2.html

Offline mainengine

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Re: Shuttle Questions Q & A (Part 3)
« Reply #47 on: 01/21/2007 02:01 PM »
Quote
Jim - 21/1/2007  8:48 AM

Quote
nathan.moeller - 21/1/2007  9:43 AM

Hey Jim.  That reminds me of another question.  Including those currently installed on the orbiters, how many useable SSMEs are currently in existence?

there is a list on L2

A list ? Where is it ?

Offline Jorge

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RE: Shuttle Questions Q & A (Part 3)
« Reply #48 on: 01/21/2007 04:16 PM »
Quote
mkirk - 20/1/2007  7:33 PM

Quote
Jorge - 20/1/2007  2:54 PM

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Argosy - 20/1/2007  2:40 PM

Here a question I've been interested in for some time...

What is the maximum achievable delta-v of the shuttle if all the fuel would be burnt out during it's climb, and the shuttle would be empty(no cargo whatsoever, just the skeleton crew)?

Only about 500 fps more than a nominal HST launch. The resulting orbital altitude would be around 600 n.mi.
--
JRF

Yeah, but your use of the word "skeleton crew" may be a poor- although very acurate - choice of words in this case.  

Strictly speaking, it was Argosy's use, not mine...

Quote
Don't let that pesky little desire to come back home get in the way of a maximum performance altitude record.  Heck lets really go for broke and use up all the gas in the RCS by using the +x and -x jets as well.  Of course we can save just enough propellant for one more attitude change to a right wing forward orientation (i.e. along the velocity vector) which would allow us to blow the hatch and get just one more burst of Delta V as the cabin vents every ounce of remaining O2 and N2 in the ECLSS (environmental control and life support system) out through the open hatch...that would be cool ;)  :)

Mark Kirkman

OK, call it another 100 fps from each pod, for a total of 800 fps. The cabin vent, as cool as it sounds, will probably produce negligible delta-V (though it will spin the orbiter quite spectacularly...). From a nominal 300 nmi HST orbit that will get us to a max apogee around 820 nmi, or a circular orbit around 550 nmi.

Alternatively, let's say we never circularized our 300 nmi HST orbit, buying back that amount of OMS. Now we're starting at 300x100 nmi with around 1150 fps to burn at perigee. That could yield a max apogee of almost 1100 nmi.
--
JRF
JRF

Offline Jorge

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Re: Shuttle Questions Q & A (Part 3)
« Reply #49 on: 01/21/2007 04:17 PM »
Quote
elmarko - 21/1/2007  7:38 AM

I would be interested in that! I'm also tempted to run a sim in Orbiter too :P

To clarify the rules, are we going for the highest circularised orbit, or can we just shoot upwards at 90deg pitch and burn out every propellant available? :p

You'll get max altitude burning along the velocity vector, not upwards... :p
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JRF
JRF

Offline TJL

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Re: Shuttle Questions Q & A (Part 3)
« Reply #50 on: 01/21/2007 05:51 PM »
I have a question regarding the last 2 light weight external tanks used to launch the shuttle.
With super light weight tanks already flying why did STS-99 (which had a relatively heavy payload) and STS-107 use the older type tanks?
I guess the same can be asked of STS-7 and 8. STS 7 used a heavy weight tank (STS-6 flew with the first LWT) and flew a heavier payload than STS-8 which used a LWT.
Thank you.

Offline Jim

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Re: Shuttle Questions Q & A (Part 3)
« Reply #51 on: 01/21/2007 07:48 PM »
Because the payloads on those missions didn't require the extra performance gained by a lighter tank.  The missions that used heavier tanks, did so because they could afford to and it allowed NASA to "use up" the heavier tanks and get them out of the inventory

Offline Fred Clausen

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Re: Shuttle Questions Q & A (Part 3)
« Reply #52 on: 01/22/2007 06:09 AM »
Quote
mainengine - 21/1/2007  8:01 AM
A list ? Where is it ?

It is on the pay portion of this site, also known as "L2". It is very much worth the money to join.
Fred Clausen

Offline joebacsi

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RE: Shuttle Questions Q & A (Part 3)
« Reply #53 on: 01/22/2007 02:34 PM »
What was the highest orbit the Shuttle was ever sent up to?

Offline Jorge

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RE: Shuttle Questions Q & A (Part 3)
« Reply #54 on: 01/22/2007 04:02 PM »
Quote
joebacsi - 22/1/2007  9:34 AM

What was the highest orbit the Shuttle was ever sent up to?

STS-82 in 1997. Semimajor axis 3,781 n.mi., average orbital height 337 n.mi.

All of the highest shuttle orbits were on HST servicing missions, except for STS-95, which was flying a "simulated" HST orbit for one of its payloads, the HST Orbiting Systems Test (HOST).
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Offline elmarko

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Re: Shuttle Questions Q & A (Part 3)
« Reply #55 on: 01/22/2007 04:41 PM »
For the record I just sent up a shuttle in Orbiter at 90deg pitch and burned out every single propellant there is and attained a maximum altitude of about 7,500km (I forget the exact figure). That was with errors in the path though, sometimes my flight path wasn't pointing straight up. Also the shuttle in Orbiter does seem to be a bit more powerful in the first stage than the real life one.

Ground speed coming through the atmosphere was a slightly toasty 8,000 m/s.

I know this has no bearing on real world applications, but it was brought up, and Mark gave me the idea with his post :)

Edit: Fixed dodgy unit of measurement

Offline Jorge

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Re: Shuttle Questions Q & A (Part 3)
« Reply #56 on: 01/22/2007 05:57 PM »
Quote
elmarko - 22/1/2007  11:41 AM

For the record I just sent up a shuttle in Orbiter at 90deg pitch and burned out every single propellant there is and attained a maximum altitude of about 7,500m/s (I forget the exact figure). That was with errors in the path though, sometimes my flight path wasn't pointing straight up. Also the shuttle in Orbiter does seem to be a bit more powerful in the first stage than the real life one.

Ground speed coming through the atmosphere was a slightly toasty 8,000 m/s.

I know this has no bearing on real world applications, but it was brought up, and Mark gave me the idea with his post :)

7,500 m/s is a speed, not an altitude... you sure you were looking at the right gauge? :)
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JRF

Offline elmarko

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Re: Shuttle Questions Q & A (Part 3)
« Reply #57 on: 01/22/2007 06:21 PM »
oh, sorry, i meant km :p

And then i did mean m/s for the second measurement :)

Offline TJL

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Re: Shuttle Questions Q & A (Part 3)
« Reply #58 on: 02/02/2007 02:05 AM »
What was the first shuttle mission to use 104.5% thrust on the SSME's?
Any talk of increasing the thrust before the program ends for one of the heavier payload missions?
For the 50,000 + pound payload on Columbia's STS-93 mission, was the thrust level 104.5%?
Thanks!

Offline nathan.moeller

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Re: Shuttle Questions Q & A (Part 3)
« Reply #59 on: 02/02/2007 03:15 AM »
Quote
TJL - 1/2/2007  9:05 PM

What was the first shuttle mission to use 104.5% thrust on the SSME's?
Any talk of increasing the thrust before the program ends for one of the heavier payload missions?
For the 50,000 + pound payload on Columbia's STS-93 mission, was the thrust level 104.5%?
Thanks!
]

Thrust level will not increase for heavier payloads.  Heaviest ISS payloads were about 18 tons (P6, P3/P4, S3/S4, S6) and didn't require extra thrust.  I'm sure it wasn't increased for the STS-93 launch.  That was the heaviest payload ever hauled into orbit by a shuttle (25 tons).  So if it didn't require extra thrust, the ISS payloads don't and will not.  In any case, I think the highest possible thrust level is 107%.  They had the option of using it for a while in the early days should an ATO case be ordered.  They wouldn't use it in the dense lower/middle atmosphere due to aerodynamic loading on the vehicle.
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