Posted on 10/09/2007 7:46:20 PM PDT by Reaganesque
What I’m wondering is, how scalable is this design?
5,000 ft^2 of cabin space is the size of a pretty large suburban house. Could they build a smaller version with something like 1,000 ft^2 of cabin space, more like an airborne houseboat than an airborne megayacht? Or, for that matter, one with 20,000 ft^2, an airborne cruise liner (which was the original Zeppelin ideal).
There's a strong appeal there -- get the rocket into the upper atmosphere, lowering the escape velocity, with zero fuel expenditure, and then fire. from there, it's a short hop to thinking about using gaseous H2 for both buoyancy and fuel. When I was a kid, I noodled around with the idea, and even sketched out some designs, but it's probably for the best that I never took it to the model rocketry, might-blow-your-dumb-self-up stage.
It might be more plausible now than in the past, because now we have composite materials that remove a lot of the weight. But we also, through the Shuttle program, have gotten better with solid-fuel rockets -- in bang-for-the-buck terms, it would probably make more sense to lift a solid-fueled rocket with He than to try to fuel it with H2. And that's leaving aside the non-trivial task of getting a sufficiently precise launch vector from a platform that's literally floating in the wind.
It does seem a bit retro to go back to blimps for lift, yes? But that doesn’t mean we can’t have FUN with a pipe dream like this. Ok, you’ve got a 3 g acceleration limit for human bodies. So let’s say we have a HUGE hydrogen filled pumpkin balloon with ribs/bumps(NASA has already designed pumpkin balloons for floating around in mars/venus atmospheres). The center is pinched down to a sabot-ring which in turn holds the space rocket.
Now let’s say the pumpkin balloon gets you to 35,000 ft. The sabot-ring contains LOX and has several smaller bottom rockets as well. Thus the H2 from the balloon and LOX lifts the whole thing to 50,000 ft to 60,000 ft; at which point the balloon is drained and the space rocket fires(sabot release). Perhaps solid rocket boosters alone may get you to LEO(no liquid propellant).
As to a precise launching point, the STS cost reduction may well justify CLOSE ENOUGH. It’s very easy to change orbits once in space, heck, even tiny little ion rockets will do it, if you’re patient enough...
Ah well, it’s a zany idea, but then...where would we be if people in the past hadn’t asked : what if....
My understanding of the project is that it was originally designed for military heavy lift capability so, that’s why its so huge. I don’t see why this couldn’t be scaled down a bit. Check out their website, they may already have something on the drawing boards.
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