http://www.heinleinsociety.org/thsnexus/

The DC-X Lives!
http://www.heinleinsociety.org/thsnexus/viewtopic.php?f=9&t=1450
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Author:  PeterScott [ Mon Jul 08, 2013 7:30 pm ]
Post subject:  The DC-X Lives!

Where have I seen this before?

Author:  JamesGifford [ Tue Jul 09, 2013 5:29 am ]
Post subject:  Re: The DC-X Lives!

Unless you meant to link to an article about prison strikes, the link is bad.

Author:  JackKelly [ Tue Jul 09, 2013 7:54 am ]
Post subject:  Re: The DC-X Lives!

I was expecting an article about the DC-10.

Author:  PeterScott [ Wed Jul 10, 2013 5:18 am ]
Post subject:  Re: The DC-X Lives!

Oops, paste fail. Edited. Try again please.

Author:  JackKelly [ Wed Jul 10, 2013 5:35 am ]
Post subject:  Re: The DC-X Lives!

That is so freaking completely awesome. Seems to go a long way toward realizing Heinlein's vision of single-stage rocket ships.

Thanks for sharing.

Author:  JamesGifford [ Wed Jul 10, 2013 6:23 am ]
Post subject:  Re: The DC-X Lives!

Way cool to watch, but two words occur to me: fuel costs.

The problem with this kind of design is that as much fuel, or more, is required for landing as for takeoff. I can't envision a working model that would have a meaningful payload and carry enough fuel for even a single takeoff and landing with safety reserves.

Until and unless we develop propulsion systems with much greater delta-vee per pound, unpowered descent and landing will be the only workable spaceflight option.

I know, I'm such a wet blanket.

Author:  PeterScott [ Wed Jul 10, 2013 11:39 am ]
Post subject:  Re: The DC-X Lives!

JamesGifford wrote:
Way cool to watch, but two words occur to me: fuel costs.


Very logical argument, but... SpaceX is perfectly capable of making the cost benefit calculations. Either they're doing this solely for gee-whiz PR, or they have something up their sleeve.

Author:  jeepojiii [ Wed Jul 10, 2013 2:21 pm ]
Post subject:  Re: The DC-X Lives!

That better be a big sleeve. :lol:

Author:  beamjockey [ Wed Jul 10, 2013 3:57 pm ]
Post subject:  Re: The DC-X Lives!

JamesGifford wrote:
Way cool to watch, but two words occur to me: fuel costs.

The problem with this kind of design is that as much fuel, or more, is required for landing as for takeoff.

It's a rocket. When it is landing, the propellant it took off with is long gone. Therefore, by the cruel equation of Tsiolkovsky, the thing that's landing weighs much less than the thing that took off. Correspondingly less propellant is needed.

Quote:
I can't envision a working model that would have a meaningful payload and carry enough fuel for even a single takeoff and landing with safety reserves.

I agree that this is a quantitative question. But wings weigh something, and parachutes weigh something. If the tradeoffs against these are favorable, then hauling landing propellant along all the way through the mission might possibly be the right answer. Certainly some engineers have thought so.

Even a Soyuz lands by firing retrorockets at the last moment of its parachute descent. Which is nothing like the kind of vehicle we're discussing-- but it does indicate that someone thought it worthwhile to carry solid-fuel rockets all the way into orbit and back.

If memory serves, the never-built descendants of the DC-X, when returning from orbit, were expected to use the atmosphere to slow down to a modest speed, as capsules and Shuttles do, but to conduct a powered tail-first landing.

I have an open mind on the question.

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