Re: starship-design: Planetary Landing

[Steve VanDevender <stevev@efn.org>]

Jonathan J Jay writes:
 > You wrote:
 > 
 > >Why would you want to land on a planet anyway?
 > 
 > You may be spending long amounts of time on one planet at a time; it
 > would be easier just to bring the entire ship down to the planet rather
 > than making plenty of ship to planet transports, and possibly cheaper,
 > depending on the amount of planets you studied.

No, that's not necessarily the case at all.

Building an interstellar ship that can take the structural
stresses of atmospheric entry and landing, and hold enough fuel
to perform landing and return to orbit, and do this reliably more
than once, is an amazingly difficult task.

A ship that is built to stay in space, especially a large ship
that can support a large crew on a multi-year journey, will be
much, much lighter than one capable of landing itself, and
therefore require less fuel for its journey.  And so far one of
the biggest technical problems we face in designing an
interstellar starship is that, _at best_, a ship capable of
fairly fast relativistic travel requires at least as much fuel
mass as payload mass, and that's if you use antimatter as the
fuel.

At the scale we're talking about, I really do think the only
viable option is to have landing craft carried on the ship.  If
we can build an interstellar spacecraft, I'm sure we can build
self-powered orbit-capable landing craft.  I really don't think
we can build an entire large starship that can land itself.  Stop
watching _Star Trek: Voyager_; it's rotting your brain.