The original Kistler proposal (before the "improvements") was a quite nice TSTO with a dumb Launch Assist Platform that lifted the upper stage clear of the atmosphere straight up. The upper stage separated and the
LAP dropped straight back down to the launch site.
Yes. You'll have noticed that they dropped this plan; I haven't seen anywhere why, but I think I know.
I've always rather liked this idea
Me too; until I simulated it.
I told my simulation program that the first stage had to land trivially west of where it took off from- and by the way it had to be a trajectory that makes orbit (going east!) with the second stage. It found an interesting trajectory that relied on coriolis from the rotation of the earth that permitted it to give a small boost to the second stage, which then made orbit.
However, compared to a similar construction TSTO I found my payload dropped precipitously, by 75%.
That's *really* bad.
So I have to either build my launch vehicle 4x bigger or launch 4x more often. IMO neither seems like a brilliant idea. I think the costs go up by 4x, and then you have to claw it back by making your launch vehicle more reusable... but adding reusability also costs payload... it's rather a slippery slope.
Anyway, it wasn't just my program, since I've run my simulation I've learnt that apparently Boeing did a study in the 60s which showed much the same thing- doing this loses you 65-80% of your payload capacity.
At the end of the day, IMHO a conventional flyback booster scheme is probably the best solution for accessing space. I quite like SSTO also, but the payload size is likely to be small, and the margins thin.
Additionally, tethers also look pretty promising too; SSTO to a skyhook- that works- or even just climbing up the space elevator- some people think that a practical space elevator cable technology is only about 2 years out- the materials science is looking *very* promising.
......Andrew
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