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First stage winged, air breathing rocket combo?

Posted by: lightningbob - Thu Aug 02, 2012 10:38 pm
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First stage winged, air breathing rocket combo? 
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Post First stage winged, air breathing rocket combo?   Posted on: Thu Aug 02, 2012 10:38 pm
Would it be advantageous to make a "stage 1" craft (like white knight and the new Rutan heavy lift plane) that could take a ship
to a ten mile alt. then fire rockets to climb to a 30 mile alt (give or take) then seperate and launch the second stage orbiter from there?
Whould the added altitude, speed and thinner atmosphere make for a very small second stage?
It would be interesting to see the data on launching a 1,000 lb payload under those conditions.
I assume the first stage would be totally resusable :D


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Post Re: First stage winged, air breathing rocket combo?   Posted on: Fri Aug 03, 2012 1:58 am
One of the points of staging, esp. for winged, airbreathing things, is that they can be optimized for a flight domain. Flying from low alt. to high has different characteristics than going from high to hypersonic. You are compromising the design and giving away the prime advantage of the configuration.


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Post Re: First stage winged, air breathing rocket combo?   Posted on: Fri Aug 03, 2012 10:32 pm
lightningbob wrote:
Would it be advantageous to make a "stage 1" craft (like white knight and the new Rutan heavy lift plane) that could take a ship
to a ten mile alt. then fire rockets to climb to a 30 mile alt (give or take) then seperate and launch the second stage orbiter from there?
Whould the added altitude, speed and thinner atmosphere make for a very small second stage?
It would be interesting to see the data on launching a 1,000 lb payload under those conditions.
I assume the first stage would be totally resusable :D


I think DARPA wants to do this with its ALASA program:

To Keep a Steady Stream of Satellites Going Up, DARPA Wants to Launch Them from Airplanes.
By Clay DillowPosted 11.07.2011 at 3:56 pm
http://www.popsci.com/technology/articl ... -airplanes

Bob Clark

_________________
Single-stage-to-orbit was already shown possible 50 years ago with the Titan II first stage.
Contrary to popular belief, SSTO's in fact are actually easy. Just use the most efficient engines
and stages at the same time, and the result will automatically be SSTO.
Blog: http://exoscientist.blogspot.com


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Post Re: First stage winged, air breathing rocket combo?   Posted on: Sat Aug 04, 2012 5:57 pm
How is that different than what Orbital Sciences already does?

And,

"In a scenario in which systems like GPS and military intelligence or communications satellites are compromised, the military could quickly replenish its satellite supply from any airfield on the planet."

Has a great potential of creating or snowballing the orbital debris problem.


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Post Re: First stage winged, air breathing rocket combo?   Posted on: Mon Aug 06, 2012 12:45 am
Actually I had (and posted) this idea five years ago. I also see that it is being seriously considered by at least three different sources. Space-X and Burt Rutan, Virgin Galactic and the U.S. Airforce. My thought was to get as much altitude with stage one so stage two could be smaller. At a ten mile alt. the wings would be of little use due to the thin air but rockets could carry them even higher and and could be built to be reusable with low maint parts. So the biggest expence is fuel. Stage two is also reusable with low maint parts (compared to the shuttle for instance). Now the funny thing about getting into orbit is smaller payloads are less expensive than heavy ones. With heavier loads you need more fuel. More fuel creats a heavier rocket so now you need ....even more fuel. So I'm thinking a ship to carry 10 passengers at 250 lbs each (them + any luggage) plus two pilots/crew would be a "payload" of 3,000 lbs, much smaller than what most rockets are designed to carry. I hear alot about the "need" for a heavy lift vehicle but if I had this I think I could charge $100,000 per seat and be profitable. I also think I could get a 300 person station into orbit for the cost of the station and the fuel but thats a different topic.


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Post Re: First stage winged, air breathing rocket combo?   Posted on: Mon Aug 06, 2012 1:59 pm
It's counter-intuitive, but it's the other way around even for re-useable systems. While yes, on an individual flight basis a smaller vehicle is "cheaper" than a larger one. On a per unit of mass, a larger lifter is more efficient and cheaper. There is a ratio of payload to total mass that gets better the bigger you go. Your "fixed cost" per launch favors fewer and bigger. Everything from the costs of consumable components and the labor to assemble them to the costs of launch license and launch facilities. Propellants are only a small part of those costs.


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Post Re: First stage winged, air breathing rocket combo?   Posted on: Mon Aug 06, 2012 10:48 pm
DOH!!! now I feel stoopid. I was comparing a rocket to rocket launch I.E. one 1,000 lb payload vrs one 2,000 lb pay load price per pound the 1,000 lb rockets wins until you launch two 1,000 lb rockets to equal the payload of the other rocket. That is unless the 2,000 lb rocket uses more than two times the fuel wich I doubt.

I still want the second stage as small as possible and would push for a higher alt with the first stage.


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Post Re: First stage winged, air breathing rocket combo?   Posted on: Mon Aug 06, 2012 10:49 pm
....man can't wait till I'm a space station member.


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