Author Topic: Can SSMEs act as a restartable upper stage engine?  (Read 6960 times)

Offline jjknap

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Re: Can SSMEs act as a restartable upper stage engine?
« Reply #20 on: 07/04/2010 02:40 AM »
I am not an expert, but a couple things come to mind when you talk about restart of a SSME:
1.  If you are using liquid hydrogen and oxygen, wouldn't you have a limited time to restart anyway based on the ability of the stage to keep the fuel at the correct temperature?

2.  I remember that the Saturn V third stage had to have small rocket engines that had to fire prior to the restart in order to push the fuel towards the engine.  I would think you would need this same type of setup if using liquid hydrogen and oxygen on a stage that you wanted to use for other things beyond LEO.
« Last Edit: 07/04/2010 02:41 AM by jjknap »

Offline FinalFrontier

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Re: Can SSMEs act as a restartable upper stage engine?
« Reply #21 on: 07/04/2010 03:10 AM »
I am not an expert, but a couple things come to mind when you talk about restart of a SSME:
1.  If you are using liquid hydrogen and oxygen, wouldn't you have a limited time to restart anyway based on the ability of the stage to keep the fuel at the correct temperature?

2.  I remember that the Saturn V third stage had to have small rocket engines that had to fire prior to the restart in order to push the fuel towards the engine.  I would think you would need this same type of setup if using liquid hydrogen and oxygen on a stage that you wanted to use for other things beyond LEO.
We were discussing options that would not require restart capability. Also discussing whether such a capability is feasible, although Ares 1 is a fair demonstration of why its probably not.....
3-30-2017: The start of a great future
"Live Long and Prosper"

Offline kch

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Re: Myth: The SSME can act as an upper stage engine
« Reply #22 on: 07/04/2010 03:20 AM »

It was interesting that Apollo 7 did not have the restart stuff on their S-IVB.  That saves some weight, not sure how much.

1500 lbm.


IIRC, all the S-IVBs used on Saturn IBs were that way (no TLI, so no need to restart).

Offline Jorge

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Re: Myth: The SSME can act as an upper stage engine
« Reply #23 on: 07/04/2010 03:32 AM »

It was interesting that Apollo 7 did not have the restart stuff on their S-IVB.  That saves some weight, not sure how much.

1500 lbm.


IIRC, all the S-IVBs used on Saturn IBs were that way (no TLI, so no need to restart).

I believe that is correct.
JRF

Offline edkyle99

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Re: Myth: The SSME can act as an upper stage engine
« Reply #24 on: 07/04/2010 03:57 AM »

so what exactly is 103? A core with a second stage using 2 j2x (rs 68 first stage?) A bit confused, I though 103 was a proposal to use 2 j2xs on the EDS for ares v.......
Concept 103, the kerosene rocket idea, was first publicly described in the following document.  It illustrates the cost savings potential of entirely abandoning Shuttle-Derived.
http://nspires.nasaprs.com/external/viewrepositorydocument/cmdocumentid=238644/HLLV%20Study.pdf

 - Ed Kyle
« Last Edit: 07/04/2010 03:57 AM by edkyle99 »

Offline JosephB

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Re: Can SSMEs act as a restartable upper stage engine?
« Reply #25 on: 07/04/2010 07:35 PM »
One of many things that are very interesting in that document is the Upper Stage engine possibility noted for concept 103. RS-68B E/O. Uffda!

Offline JosephB

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Re: Can SSMEs act as a restartable upper stage engine?
« Reply #26 on: 07/04/2010 07:48 PM »
I agree with Ed though. A dual US/EDS makes a lot of sense.

Better yet, how about both?
J-2X for BEO
68B for heavy LEO payloads?
« Last Edit: 07/04/2010 08:01 PM by JosephB »

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