Why the large differential in trips to Mars?

On Fri, 17 Aug 2012 15:05:52 -0700 (PDT), bob haller
wrote:

mars society had that proposal for mars direct including in situ production of fuel for the return trip to mars.

now that same fuel could be used tp power the station?

Circular reasoning. In-situ production requires power.

"My base has power to make in-situ fuel production, therefore I can
use that in-situ fuel to make power for my base."

Nope. Doesn't make sense.

Brian

In article , bthorn64
@suddenlink.net says...

On Fri, 17 Aug 2012 15:05:52 -0700 (PDT), bob haller
wrote:

mars society had that proposal for mars direct including in situ production of fuel for the return trip to mars.

now that same fuel could be used tp power the station?

Circular reasoning. In-situ production requires power.

"My base has power to make in-situ fuel production, therefore I can
use that in-situ fuel to make power for my base."

Nope. Doesn't make sense.

The only possible way it makes sense is if you're using solar power and
using some of the fuel/oxidizer to produce power for the base at night.
But as others have noted, solar doesn't make much sense on Mars,
especially if you need a lot of power (e.g. to make fuel and oxidizer
for the return trip).

If your base is nuclear powered (which seems likely), then you're
absolutely right, you won't need any fuel/oxidizer to power the base.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

fuel production is a function of time and power...

realtively low power solar for a number of years could create enough
fuel to run a station for a time.....

it would be a juggling act to decide how many years solar would have
to create fuel for base operations for 2 years.......

ideally the fuel would be on site complete before the crew left earth

Hmm, maybe my post about the problems of manned missions to mars has not
got to this server for some reason...
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Ramon F. Herrera" wrote in message
...

I read somewhere that a manned trip to Mars would take years. The
"Curiosity" probe, however, took only 8 months.

TIA,

-Ramon