Author Topic: SSTO challenge  (Read 124206 times)

Offline tnphysics

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SSTO challenge
« on: 05/08/2010 03:47 pm »
Here is a challenge: Design a concept (BOTE) for an SSTO RLV. It must be capable of high flight rates (several times per day). Market is space tourism. An NTR is allowed, but air-launch is not.

Offline Jorge

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Re: SSTO challenge
« Reply #1 on: 05/08/2010 03:52 pm »
Here is a challenge: Design a concept (BOTE) for an SSTO RLV. It must be capable of high flight rates (several times per day). Market is space tourism. An NTR is allowed, but air-launch is not.

If I had a BOTE design I actually thought would work, I'd be pitching it to investors in secret, not to an online forum in public.
JRF

Offline tnphysics

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Re: SSTO challenge
« Reply #2 on: 05/08/2010 05:45 pm »
Well, I am assuming one can use an NTR, which may not be politically feasible.

Offline Warren Platts

Re: SSTO challenge
« Reply #3 on: 05/08/2010 06:03 pm »
Easy, just do it on the Moon. 4 RL-10 motors, single tanks for LO2 and H2, horzontal landing capability, with a total dry mass of about 10 tons.
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."--Leonardo Da Vinci

Offline hop

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Re: SSTO challenge
« Reply #4 on: 05/08/2010 10:00 pm »
Easy, just do it on the Moon. 4 RL-10 motors, single tanks for LO2 and H2, horzontal landing capability, with a total dry mass of about 10 tons.
Do it on Deimos, then all you need is a bicycle and a ramp :)

Offline kraisee

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Re: SSTO challenge
« Reply #5 on: 05/08/2010 10:02 pm »
A YouTube moment...

:)

Ross.
« Last Edit: 05/08/2010 10:03 pm by kraisee »
"The meek shall inherit the Earth -- the rest of us will go to the stars"
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Offline tnphysics

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Re: SSTO challenge
« Reply #6 on: 05/09/2010 12:20 am »
I suspect that ELV can be done using an ACES variant (it has a high enough mass ratio). The question is then: Can it be made an RLV?

Offline hop

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Re: SSTO challenge
« Reply #7 on: 05/09/2010 01:45 am »
I suspect that ELV can be done using an ACES variant (it has a high enough mass ratio). The question is then: Can it be made an RLV?
The billions spent on RLV studies and development over the last 50 years says: Not for a price anyone is willing to pay. There is a vast body of serious work on this subject, which a BOTE forum post is unlikely to improve on in any way. Hint, google "ssto" or "single stage to orbit".

NTR isn't likely to help you, it's a lousy first stage even if you ignore  environmental problems. Orion can do it no problem, but the EIR is going to be a doozy and the neighbors are going to complain.

SSTO ELVs aren't a problem, if you are willing to accept very low payload fractions, the required mass rations have been within reach since the sixties. The question is whether it is worthwhile, and the answer to date appears to be a resounding no.

Offline neilh

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Re: SSTO challenge
« Reply #8 on: 05/09/2010 02:19 am »
Are thrust-augmented nozzles allowed?
Someone is wrong on the Internet.
http://xkcd.com/386/

Offline Downix

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Re: SSTO challenge
« Reply #9 on: 05/09/2010 02:28 am »
I have one, too expensive tho.  Fundimentally I'd be working off of the Rockwell X-33 proposal with one addendum, an integrated booster stack of 4 SRB, their shells being part of the ablative TPS. 
chuck - Toilet paper has no real value? Try living with 5 other adults for 6 months in a can with no toilet paper. Man oh man. Toilet paper would be worth it's weight in gold!

Offline tnphysics

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Re: SSTO challenge
« Reply #10 on: 05/09/2010 03:07 am »
I suspect that ELV can be done using an ACES variant (it has a high enough mass ratio). The question is then: Can it be made an RLV?
The billions spent on RLV studies and development over the last 50 years says: Not for a price anyone is willing to pay. There is a vast body of serious work on this subject, which a BOTE forum post is unlikely to improve on in any way. Hint, google "ssto" or "single stage to orbit".

NTR isn't likely to help you, it's a lousy first stage even if you ignore  environmental problems. Orion can do it no problem, but the EIR is going to be a doozy and the neighbors are going to complain.

SSTO ELVs aren't a problem, if you are willing to accept very low payload fractions, the required mass rations have been within reach since the sixties. The question is whether it is worthwhile, and the answer to date appears to be a resounding no.

What about the GCNR proposal?

Offline tnphysics

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Re: SSTO challenge
« Reply #11 on: 05/09/2010 05:16 pm »
Are thrust-augmented nozzles allowed?
Yes

Offline meiza

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Re: SSTO challenge
« Reply #12 on: 05/09/2010 06:03 pm »
Superstrong, light and heat resistant graphene tanks and an SSME or a few, use a skirt for stability or tumbling to avoid re-entering engine first, fall into the ocean, recover by ship and wash the engines.
Very expensive to design, build and use and tedious, workforce intensive, incapable of high flight rates, unreliable and dangerous as well.

Average ISP perhaps 4200 m/s so a generous 11 km/s delta vee needs a mass ratio of 13. Low acceleration off the pad and very high acceleration in later parts of the flight.

1 ton = 1000 kg:
300 tons gross, 2xSSME, 23 tons dry, which is 6 tons engines, 1 ton other stuff, 15 tons tanks + skirt + intertank + thrust structure + fairing + payload mount, 1 ton payload. Liftoff T/W 1.2. End T/W 16 so that's an acceleration of 16 gees.
« Last Edit: 05/09/2010 06:12 pm by meiza »

Offline mlorrey

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Re: SSTO challenge
« Reply #13 on: 05/09/2010 06:06 pm »
Here is a challenge: Design a concept (BOTE) for an SSTO RLV. It must be capable of high flight rates (several times per day). Market is space tourism. An NTR is allowed, but air-launch is not.

Multiple flights per day is not physically necessary for an orbital launcher for the simple reason that once you get to orbit, it typically takes 1-2 days to catch up to and dock with your destination, or to reach the proper orbital position to launch a satellite with an upper stage. So any orbital mission is going to take, at a minimum, 2-4 days of flight time.

What is important is that one needs to be able to launch multiple vehicles per day, and turn a vehicle around quickly to launch again, in less than 24 hours.
« Last Edit: 05/09/2010 09:00 pm by mlorrey »
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Offline Cinder

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Re: SSTO challenge
« Reply #14 on: 05/09/2010 07:10 pm »
Skylon?
NEC ULTIMA SI PRIOR

Offline hop

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Re: SSTO challenge
« Reply #15 on: 05/09/2010 08:47 pm »
What about the GCNR proposal?
Which GCNR proposal ? If you have a specific one in mind you think is credible for ground launch, why not post your own sketch ?

If all you are saying is that some paper GCNR has a paper ISP of 3000, so what ? I have it on good authority that fairy dust has an theoretical ISP of eleventy gajillion.

Offline tnphysics

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Re: SSTO challenge
« Reply #16 on: 05/09/2010 09:33 pm »

Offline A_M_Swallow

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Re: SSTO challenge
« Reply #17 on: 05/09/2010 10:25 pm »
Superstrong, light and heat resistant graphene tanks and an SSME or a few, use a skirt for stability or tumbling to avoid re-entering engine first, fall into the ocean, recover by ship and wash the engines.
Very expensive to design, build and use and tedious, workforce intensive, incapable of high flight rates, unreliable and dangerous as well.

Average ISP perhaps 4200 m/s so a generous 11 km/s delta vee needs a mass ratio of 13. Low acceleration off the pad and very high acceleration in later parts of the flight.

1 ton = 1000 kg:
300 tons gross, 2xSSME, 23 tons dry, which is 6 tons engines, 1 ton other stuff, 15 tons tanks + skirt + intertank + thrust structure + fairing + payload mount, 1 ton payload. Liftoff T/W 1.2. End T/W 16 so that's an acceleration of 16 gees.

By simply switching one of the engines off the thrust drops to 8 gees.

Offline hop

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Re: SSTO challenge
« Reply #18 on: 05/09/2010 11:15 pm »

Offline KelvinZero

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Re: SSTO challenge
« Reply #19 on: 05/09/2010 11:51 pm »
What about the GCNR proposal?
Which GCNR proposal ? If you have a specific one in mind you think is credible for ground launch, why not post your own sketch ?

If all you are saying is that some paper GCNR has a paper ISP of 3000, so what ? I have it on good authority that fairy dust has an theoretical ISP of eleventy gajillion.

Sounds like you might be referring to my beamed moon dust concept. That achieved eleventy.2 gajillion and the the only significant technological hurdle was a sense of humour. :)

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