# Re: why 30? one good woman will suffice/SPIKE

Spike Jones (spike66@ibm.net)
Fri, 02 Apr 1999 23:34:20 -0800

> Spike Jones wrote:
> > The minimalist approach requires no technology that we dont already...

> Bartley R. Troyan wrote:Do you really think that the cost of sending one person to
> raise a group of 10-20 kids from embryos all the way to a productive age (early
> teens?), is lower than the cost of getting 10-20 adults and the stuff
> they need to survive and thrive to mars?...

Bartley, that is a goooood question. I went at this problem strictly from a propulsion engineer's point of view, with little regard for some of the more practical difficulties. Some of the payload scales to the size of the crew, and some of it does not. For instance, the food requirements are directly proportional to the size of the crew. Same for water and waste recycling facilities. The size of the habitation module might not be directly proportional to the size of the crew.

Consider pressure vessels: suppose you develop some type of plant that grows in liquid water under artificial light. You need to maintain the vapor pressure of water at, say 20C, plus some margin. I imagine you would be in the neighbor hood of 10 to 20 kilopascals against an outside pressure of about 2 kPa. Nowthen, a pressure vessel's mass is directly proportional to its volume, given constant pressure. Reasoning: the volume of a given container increases as the cube of its linear dimension. The surface area increases as the square of the linear dimension, however, for a given pressure requirement, the required thickness of the vessel increases directly proportional to the linear dimension. Therefore, the mass of an ideal pressure vessel is proportional to its volume. So, twice the crew, twice the required mass of a farm module.

> I don't know if even the most
> motivated single mom is going to have time to grow/manufacture the food
> they all need...

Ah, but would she not be highly motivated? {8-] You may be right. Read on:

> ...repair the odd broken solar array...

She may be highly dependent on semi-autonomous robots, controlled mostly by earthlings.

> ...chase toddlers...

Chase them where? I expect the hab module to be quite small. Her biggest challenge would be maintaining her sanity, assuming a child raised in a space about equal to a good sized motorhome, when neither can go outside and play, at least not for long.

Problematic for sure, but when all is said and done, it is not clear to me that the first native generation will need to be all that intelligent in the traditional sense. They need to use their brains for one thing: surviving in a hostile environment. Even still, I suspect most of their education will come in the form of signals from the home planet. Do they need to learn how to read? Why? Do they need to be able to work on machines? Absolutely.

> ...Wouldn't it be cheaper in the long run to send a group
> of somewhere from 10-50 young adults (maybe some teenagers, sure)?

OK, but before you go too far down this road, try to imagine what manner of spacecraft would be needed to carry off such a thing. Is the craft assembled in earth orbit? After how many launches? On what launcher? At what cost? Ten people soft landing on Mars requires an awesome payload.

>...The hardships faced being the first (and only) adult human living
>on another planet's surface seem to be more than one person could handle....

Again, you may be right, but consider the fact that we humans can be tough daughters of bitches. Back in the old days trappers went into the interior of America, and saw not another human for two years. Prisoners have been kept in solitary, with no books and no nothing for years, and somehow managed. Island of the Blue Dolphin: story based on reality. Young lady lived alone for 12 years on a small island. The single Martian, even without reproductive success, would have constant interaction with humans, with only a maximum of 20 minutes delay in communications, minimum of about 2 minutes.

Depends on their ages. If the oldest child were at least 8 yrs, they might make it anyway. Children can be quite resourceful if they need to be. Younger than that, they all die. Sad indeed. Im not claiming this is a low risk adventure.

Or leg? This would bad, but unlikely in 1/3 G. Landing is high risk for sure, but it only gets more difficult as the lander gets larger. It is easier to land a Cessna than 747.

> > So again, I am back to: how small could the mission be scaled? spike
>
> Not *that* small.

OK, but how small? Im thinking the single astronaut, one way trip *might* be doable for about 5 billion dollars, (\$5E9) assuming some of these low cost outfits like Kissler Engineering are successful with their low cost commie engined boosters. Im thinking you would need to soft land about 80,000 kg on Mars to give a single small astronaut a fighting chance, by which I mean about ~5 yrs of processed stored food to last until a farm module could be built from indigenous materials and operated at break-even, plus a small nuclear reactor, semiautonomous robots to build the farm module, a small foundry to process materials, a solar cell production facility, etc.

5 billion is in the neighborhood of what could be raised by enough fanatic rich people. It is two orders of magnitude cheaper than NASA estimated for a three-man flags and footprints mission, but that effort assumed a way home.

uh, no. Hes preoccupied at the moment. {8-[ In trying to brutally slay any firm that presumes to develop software anywhere other than in Redmond Washington that runs on any platform other than windows. I would be surprised if Mr. Gates has any ambitions to do something like this. Of course, I might be wrong. Hope so. spike