Ken:  Your arguments are thoughtful but you are going up against the Big Boys if you're tackling Henry.  Allen Sherzer will doubtless chime in on the subject of staggering operational costs, too.  Good luck, son.  In article <1sp513$beo@hsc.usc.edu>, khayash@hsc.usc.edu (Ken Hayashida) writes: >Shuttle is the only method in the free world of orbiting large life sciences >and medical related packages.    Ahem.  The Russians are in the Free World now, or at least it would be Politically Correct to contend so.  >I am hopeful that DC-X,  or whatever the follow-on is eventually called,  >will perform as you state.  But right now, I must admit that I am more  >skeptical than ever.    It will be tough to make DC-X succeed, and to turn it into an operational orbital vehicle.  Doubtless it will fail to meet some of the promised goals.  The reason people are so fond of it is that it's the *only* chance we have now, or will have for a *long* time to come, to develop a launch vehicle with radically lower costs.    There is no Shuttle successor in funded development, NASP is dwindling away, and ALS/NLS/Spacelifter sure as hell aren't gonna knock any zeroes off that $2000-$3000 per pound cost.   Part of the blame for this must be placed on a Shuttle program that consumes many annual billions of the, er, Free World's available space cash.  As you will no doubt hear from many correspondents in the days to come. (-:  DC-X is an attempt to break out of the vicious cycle by keeping development costs low and flying incremental "X-plane" hardware. It's been, to my mind, incredibly successful already-- they've built a complex prototype in under 600 days for under 60 megabucks.  I would have been extremely skeptical that this could be accomplished in 1990s America, never mind flying the thing, getting a successor funded, or building the DC-Y.  I'm sure you know well that launch costs are THE basic problem for any expansion of astronautics.  I don't see a realistic  prospect for beating down those costs, for multi-ton payloads, anywhere else.  If the DC flops, it'll be business as usual in space.  The Nineties and the Double-Oughts will look just like the Seventies and Eighties, a prospect too depressing to bear.  (Pegasus represents another assault on the problem from a different direction.  It doesn't lower cost-per-pound but it offers an orbital launch for under ten megabucks.  It's creating its own market for small payloads.)  I read the magazines and I've attended the last two IAFs. There are plenty of engineers with paper ideas for cheaper launch systems, some of them as good as or better than SSTO.  There is no sign in today's world that any of these designs will be allowed anywhere near an assembly line.  >You could change my view on DC-X if you could prove the following: [...deleting some things I'm not going to prove tonight...] >3  that the shuttle need not go on hiatus to allow development of a man-ratable >DC-X successor  Strawman.  Is anybody seriously proposing this?  References, please.  The DC must be developed in the real-world funding climate, which includes a NASA ferociously committed to continuing Shuttle operations, as well as the "bird in the hand" argument your common sense tells you.   If DC-Y flies at all, it flies alongside the Shuttle, not instead of it.  Also, of course, DC-Y and its operational descendants will be useful for a wide variety of jobs even if they are *not* man-rated.  >4  Most importantly, that the DC-X will open up LEO to more scientific and >technical payloads.  If a DC-X successor can fly a 10,000-kg payload for $1M, or even $5M, rather than the $40M it now costs, more people will be able to afford more payloads... for the same money, you can fly several satellites instead of one.  Big outfits can fly multi-satellite series.  Little outfits will be able to fly spacecraft of their own, instead of begging a ride.  This is just supply and demand.  You should be able to convince *yourself* that point 4 will be true, assuming DC makes a big difference in costs.  Do you have some reason to think not?