starship-design: YES, we might do it.

["Walker, Chris" <Chris.Walker@BSKYB.COM>]

> -----Original Message-----
> From:	David Levine [SMTP:david@playlink.com]
> Sent:	Monday, October 19, 1998 9:11 PM
> To:	starship-design@lists.uoregon.edu
> Subject:	RE: starship-design: YES, we might do it.
> 
	> > ----------
	> > From: 	Zenon Kulpa[SMTP:zkulpa@zmit1.ippt.gov.pl]
	> > Sent: 	Monday, October 19, 1998 9:09 AM
	> > Subject: 	Re: starship-design: YES, we might do it.
	> > 
	> > I wonder why commsats, GPS, meteoats did not have 
	> > any significant impact on lowering costs to LEO significantly?
	> > 
	> > 
	> Hm, good question!

A couple of thoughts on this:

(1) There haven't been nearly enough launches to allow for economies of
scale to come into effect. Whilst the launch of a spacecraft these days is
seen as "nothing special" (eg. compared to back in the 1960's), they are by
no means what I would describe as "commonplace".

There was a big fuss made by environmental groups when the shuttle first
rolled out, as it was said then that there were going to be something like
300 shuttle launches a year. The enviro groups were worried about the effect
this would have re. atmospheric pollution. As we know now, though, the
actual number of launches per year is something like an order of magnitude
lower. Maybe 300+ launches/year would have reduced launch costs...or maybe
there aren't that many launches because of the prohibitive costs and
complexity of each mission, not to mention that current lack of need for
that many launches. Chicken, egg...egg, chicken.

(2) Not enough reusability in the current designs of launch vehicles. Sure,
the shuttle is substantially reusable, but the extreme is a fully reusable
single stage-to-orbit vehicle. A spacecraft systems engineering book I've
just looked at (written in 1991) suggested that such vehicles could lower
specific launch costs into LEO to $500/kg. That's at least going (quite)some
way towards the figure of $100/lb mentioned on the list recently.

Any more comments on this?

Chris Walker