RE: why 30? one good woman will suffice/SPIKE

Billy Brown (
Thu, 1 Apr 1999 09:16:03 -0600

Spike Jones wrote:
> Yes, but this estimate is more optimistic than mine by an order of
> magnitude at least.
Once you consider the other necessities, I am
> surprised if we could land and sustain a nominal human on Mars
> for less than 100 million apiece, and even that may require some
> optimistic assumptions on sustainable food production once you
> get there. Let us calculate this and reconvene next week on a
> cost and weight estimate..

My "$1 million apeice" figure was based on the assumption of a massive program aimed at shipping large numbers of people. Such a program would require a high volume of big launches, which combined with the mass-production opportunities would make things a lot cheaper. Even then, it is a bit on the optimistic side.

Your figure looks pretty reasonable to me for the kind of mission you are talking about. However, talking about per-person costs is misleading in this case. Since almost all of the mass we ship is going to be equipment and supplies, cost per pound would probably be a better way of measuring things.

By that yardstick, I'm thinking an initial exploratory mission is going to cost several million dollars per pound delivered to the Martian surface. A small colony like your proposal, with a regular launch schedule and standardized hardware, should bring that down to a few hundred thousand per pound. A really aggressive program, with dozens of launches per year and lots of SSTO technology, might get that down to tens of thousands if we are lucky.

What do you thing of these numbers?

> So, Billy, how small can we make that human payload?

Even given your scenario, I don't think that is the limiting factor. If this colony is actually going to work as insurance against ultratech disasters, it needs to be fully self-sufficient by the time nanotech gets off the ground. That means that sometime between now and then we have to ship a few million tons of people, equipment and supplies (mostly equipment). Obviously, that isn't going to happen.

I think you are right to think that we can reduce this problem a bit by starting with a very small colony and having them raise children to expand their population. However, in this scenario the mass of the colonists will end up being a tiny fraction of the total mass we have to ship. As the colony expands we will still have to ship most of the equipment that the fast approach would have required. The colony will need all kinds of mining, manufacturing and construction equipment just to get a basic machine shop-type abilities. Then we'll have to ship more hardware to get other basic industries going - and there are a lot of basic industries they have to have before they reach the point of being able to make a significant fraction of their own equipment.

So, I think the real question should be: how small can we make the hardware payload?

Billy Brown, MCSE+I