"Jochem Huhmann" wrote in message
...
Nomen Nescio writes:

http://www.space.com/12489-nasa-mars...spaceship-red-
dragon.html

A daring mission where NASA will try to land SpaceX's Dragon on Mars
using its emergency escape system rocket engines. The Red Dragon will
carry more scientific gear to Mars than ALL PREVIOUS MISSIONS
COMBINED.

I REALLY want to see these magical emergency escape system rocket
engines and fuel tanks... Especially I want to see where the hell they
want to put them into the bottom of the Dragon capsule. The current puny
90 lbf engines along with tanks and other stuff (including the
parachute) don't leave that much (if any) room the

http://www.spacex.com/00Graphics/Ima...0Update/14.jpg

I'd like to suggest another variant where a SECOND Red Dragon capsule
lands next to the first one. This to practice pin-point landings. In
addition the second Red Dragon would be chockful of fuel which would
be
transferred to the first Dragon somehow. The first Red Dragon would
then lift-off and try to attain orbit, validating a possible manned
mission or making sample return with some serious cargo possible.

Surely... SSTO even on Mars requires a bit more than some tiny engines and
fuel tanks squeezed into some corner as an afterthought.

Everybody seems to be using SolidWorks these days. Well, Dragon worked
first time around so I guess it's OK.

The retro engines can probably be pointed downwards and those produce a
lot more thrust than 90lbf, otherwise the vehicle could never escape in
the event of a carrier rocket explosion. The emergency escape / retro
engines would burn the fuel a lot quicker than the maneuvering engines,
but that's ok, since when they're used the craft isn't going to need
them anyway. For the Mars mission there might be additional tanks in
the cargo area, is my guess, to do the reentry and touchdown.

I'm uncertain if SSTO of Dragon would be possible, haven't done the
maths, but there's virtually no atmosphere on Mars (so it's shape
doesn't matter much) and the gravity is 1/6th that of Earth IIRC. Also,
artwork of older sample-return missions had a incredulously puny rocket
in them, and I reckon those weren't just drawn without checking the
feasiblity first.