Re: SpaceX update or Saturn V take 2

From: richard schumacher (no-spam_at_invalid.com)
Date: 02/13/05 

Date: Sun, 13 Feb 2005 15:36:43 -0600

In article <Xns95FBD6ED28F1Ateeks99stuffyahoocom@151.164.30.44>,
 Tom Kent <teeks99stuff@yahoo.com> wrote:

> henry@spsystems.net (Henry Spencer) wrote in
> news:IBtCCo.IKJ@spsystems.net:
>
> > In article <3770n9F59ie45U1@individual.net>,
> > =?ISO-8859-15?Q?R=FCdiger_Klaehn?= <klaehn@gamemakers.de> wrote:
> >>If you have a very reliable escape system you might get by with a
> >>single engine launcher for launching humans. But an aborted mission is
> >>very bad news even if the human passengers survive it unharmed.
> >>Especially if you are planning to reuse the first stage like spacex
> >>does.
> >
> > Careful here: SpaceX is *hoping* to reuse some *components* of the
> > first stage... and last I heard (admittedly quite a while back), even
> > that was a bit speculative, as much a wish (and a PR point) as a
> > realistic hope.
>
> It looks like the reusability outlook is getting a little rosier....here's
> what Elon Musk said in his latest e-mail:
>
>
> > I am increasingly confident of the reusability of the Falcon I first
> > stage. We will soon exceed 200 cryogenic pressure cycles on the first
> > stage tank mounted in Vertical Test Stand 1 in Texas and there are no
> > signs of fatigue. The stage is also constantly wet by the water deluge
> > system and by melting ice from the LOX tank, but is showing no
> > significant corrosion.
> >
> > Although we keep telling people that Falcon I has a reusability
> > percentage roughly equal to that of the Space Shuttle, the only other
> > semi-reusable flying today, it still gets referred to as an expendable
> > rocket from time to time. I am quite confident at this point that Falcon
> > I will not only be majority reusable, assuming the parachute opens, but
> > that the economics will work out such that we may be able to make a
> > modest reduction in price from the current $5.9M, which assumes no
> > reusability value.
>
> Sounds to me like they want to make it a real reusable.

OTOH, salt sea water is probably more corrosive to first stage
components than is the fresh water of condensation to which the tanks
have been exposed. I asked Space-X about this explicitly, and they said
that they have done no immersion testing in salt water and do not plan
to. That is worrisome.