On 30/12/2015 12:42 PM, JF Mezei wrote:
On 2015-12-29 19:46, Sylvia Else wrote:

Getting there in 6 weeks requires a huge delta-V - twice, and twice more
to get back in the same time. I don't see this coming about through
incremental improvements in existing rocket designs.

Problem easily solved...

You get SLS into mass production in China. Mass production and China
should lower costs.


Second, you use an SLS to launch an SLS into Orbit.
You use 4 SLS launches to haul fuel for that first SLS.

So 5 SLS launches to get 1 SLS in orbit fully fueled with Orion at the
top, ready to GOTO (not GOSUB) Mars lickety split.

One SLS won't get an Orion to Mars in 6 weeks, even starting from Earth
orbit. Further, you need to slow down before arriving at Mars (and no,
aero-braking won't work at these speeds).

Even if one SLS were up to the task of slowing down the Orion at Mars,
you're now talking about getting an entire SLS there. How many SLSs
would be required to do that from Earth?

Now remember that you need to get the crew back in the same time. Pretty
much, that means that however many SLSs you thought you needed from
Earth now has to be placed into Orbit around Mars. To do that, you now
need to square you previous number.

Oh, no doubt it's technically possible, you just keep staging 'til it
works. But the cost, even from China...

Sylvia.