Re: VTVL?

Jonathan Goff wrote:

The last option gives by far the best performance, but at
> the cost of having to recover the first stage downrange,
> with potentially higher reentry velocities. The first
> stage can impart more of the upper stage velocity, allowing
either a smaller vehicle to be used, or more payload to be
> carried. However, there are some real flexibility challenges
> to this approach. Basically, since a given launch site is
> only going to have a few suitable downrange first-stage
recovery sites, it will be limited to being able to launch
> into a very small number of inclinations. Plus, you have
> to pay the cost of flying the first stage back to
the launch site before you can reuse it.

If you arrange your launch site such that the recovery site
is in the ocean, the range of possible recovery sites becomes
much larger. In addition, you have the option of floating
the first stage back to land rather thay flying it back.
Floating the first stage back would take longer than flying
it back, and would cut down on flight rate. However, you
also have the option of flying the smallish, but more expensive
rocket engine back to the launch site and just floating the
big bulky first stage tank back to land. This would require
multiple first stage tanks to sustain a rapid flight rate.
It might be an acceptable business/engineering trade-off.

Irrespective of whether the recovery site is on land or on
ocean, the weather at both launch and reentry site must be
acceptable. This will also adversely influence flight rate.

-Wayne
.

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