Philip Witham [p.j.witham@ieee.org] wrote:
>Sure, its human nature. But I get annoyed listening to arguments
>for/against various impractical booster concepts when it is obvious they
>are impractical.
Perhaps that's because they're actually far from obviously impractical to most of us.
>Piggybacked winged stages.
AFAIR NASA are currently testing a scramjet vehicle which will be launched from an SR-71 at Mach-3; clearly they think it's a practical proposition.
>Single stage to orbit techno-marvels that carry virtually no payload
>despite pushing all structures beyond the state of
>the art.
I know of no such vehicle; there are various SSTO designs around, but all have a significant payload. And hell, Atlas can be made into an expendable SSTO by replacing the engines. SSTO is no big deal; reusable SSTO is quite hard, but certainly feasible.
> Dozens of space shuttle main engines ganged together, all operating
>reliably, simultaneously(!).
Ok, you've got me on that one, though SSMEs are amongst the most reliable engines ever built. However, I don't know of anyone outside the government or its contractors who would suggest such a thing, simply because of the refurbishment cost between flights.
> Mid-flight propellant loading from another vehicle.
Uh, mid-air refuelling is "impractical"? I was under the impression that it was carried out hundreds or thousands of times every day by the military forces of the world.
>SCRAMLACE (liquify oxygen from the air in flight, for use out of the
>atmosphere).
Rolls-Royce think it's practical enough that they've been jealously holding onto the HOTOL patents.
Mark