Re: SCI:TECH:RFC: wooing Mona

Philip Witham (
Sun, 15 Mar 1998 17:26:50 -0800

>Mars is closer than the Moon in terms of the energy required
>to get there.  From LEO to the Moon, the delta-V is 6.0km/s whereas
>to get to Mars it's only 4.5 km/s!  The trans-mars injection is only
>a little more expensive than the Moon but the huge savings comes from
>the fact that Mars has an atmosphere you can use to slow down.  The
>Moon requires you to haul a bunch of fuel with which to stop yourself
>once you're there.

But don't forget the delta V required to get back off of mars. From the moon,
products such including metals, H2, and O2 can be launched into trans-earth
trajectories using just about anything - mechanical slinger, light gas gun,
mass driver, etc. Also, the moon is a fine place for a beanstalk or skyhook,
requiring much less of a taper ratio or strength in the cable than on Mars or

Obviously it depends on where you want to build. If you prefer being stuck at
the bottom of a gravity well, Mars is a good one. If you want to build a
self-supporting colony in the near term (pre advanced nanotech), don't you
think it's good to be within the earth-moon system, and to trade products more
quickly with less impulse?

>still (at the time of writing) over-estimated costs.  A 100% private
>venture run by seat-of-the-pants entreprenuers and pioneers could bring
>costs down even more.
I spent years working for a private space venture that spent $20-30 million,
but have become very skeptical of the likelihood of massive private space
investment as of yet. Where massive profits have already been made, the
investors come out of hiding. Until then, the barrier is too high to jump.
$1000/Lb to LEO will help.