Sunday, November 3, 2013

Proper focus of mars colonists

The Mars Design Reference Architecture 5.0 describes the systems and operations that would be used for the first three missions to explore the surface of Mars by humans.
Which is to say, right off the bat, they start with the wrong focus. Let the martian colonists explore mars after they do what they should be focused on... survival and industry both working hand in hand. Building industrial capability from the beginning increases their survival potential. Every mars colonist is going to bring with them their own set of skills. Those skill will need to take the raw elements found on mars and turn them into all the useful things they need, not just to survive but to thrive.

The basics are easy. Water is essential for life. Mars has about a liter per cubic foot of dirt just about everywhere. They need power to extract both water from dirt and oxygen from water. They need spacious habitats with regulated temperature and pressure which also requires power, with radiation mitigation that doesn't. Solar panels and batteries can provide enough power with methane engines providing supplemental high energy needs. A nuclear reactor could easily fit in a lander with terminals for cables outside making the entire thing a sealed battery providing decades of power.

As a small community, initially they will share everything. We can supply them with more food than they need every 26 months. The first step to independence is when they produce food on their own individual farmland plots. This will be the beginning of industry. They will freely trade what they individually produce with each other using the liberty to choose what they produce. Are they going to use 3D printers? We can send some raw materials for these, but martian industry should soon take over extruding ISRU plastic into suitable spools. But they don't need 3D printers to survive. It's a luxury that unfortunately gets the fascination of those that aren't thinking in terms of survival and industry. Martian needs will be much more basic. They need to be able to make things. Which means machinists, chemists and farmers and all the other skills we take for granted. They should take along an encyclopedia like this one from 1881. In less than 800 pages it includes...


Which shows not just how to use these things but how to make them from the elements. Not everything may be practical, but earth knowledge will be one of the easiest things for colonists to get (if we open our minds to pioneer requirements and not frustrate themselves with what they can't do. Can do is just can't do + time.)

If we want to prepare for living on mars we should be growing crops in filtered sunlight here on earth. Mars gets about half the sunlight that we do. Will we need mirrors to focus more light on crops? It should be simple enough to find out before we go.

Air locks are going to be essential. What's the easiest way to manufacture them on mars with their starting resources?

Another example of the wrong focus:
A strong motivating factor for the exploration of Mars is the search for extraterrestrial life.
No. That search should be made after survival and industry are established. Then they have the time to make the search. We've lived thousands of years without this knowledge. We can wait a few years while the colony gets past the dangerous years. More...
...the plan is to return the astronauts to Earth at the end of the mission.
Bad plan. There are plenty of people wanting to settle mars. Why should their seat be given to someone that doesn't? With the SpaceX Raptor engine they should be able to build their own ships when they're ready and fuel them as well. must be assumed that some microbial contamination of the surrounding martian environment would be inevitable...
Yes. human missions should be sent only to sites on Mars where this consequence is acceptable.
Give me a break. Mars has 144 million sq. km. of real estate. We aren't going to contaminate that for hundreds of years or longer. The researchers will always have pristine areas to explore.

Then yada, yada, yada about the goals of scientific exploration all of which is not even secondary to survival and building the community. Then it's heavy lift and nuclear engines both of which are not required but will delay going. Gotta use Orion? Nope.

Habitats? The first one they land in. The second one holds the entire group. Then they build their own on their own properties because ownership works.

Stopped reading after page 56.

Update: Before you can colonize, you must land. Yep, that is true. As CJ points out, SpaceX has tested some of the propulsive technology that may lead to safe landing of high mass to the surface of mars. You get around 'rocket fire into the direction of travel at hypersonic velocity' by not doing it. The superdracos are angled away from the direction of travel and are behind the heat shield. That angle has to be shallow to not lose too much thrust, but enough to avoid the problem.

Shockwaves can be shaped and may even assist in decelerating the vehicle. A configuration can be stable or unstable mainly dependent on shape. I'm confident SpaceX can put this issue behind them resulting in reliable high payload mass landers. They have certainly shown the ability to learn from experience and the ability to go at a pace set by funding (much lower funding that others seam to require.) Landing humans on mars is the key hurdle remaining for colonization. I wish others besides SpaceX were working on it, but if not I think SpaceX will git'er done.


Anonymous said...

I hope this isn't too tangential to the subject (If it is, please delete) but it is important to Mars colonization. (I'm of the opinion that landing on Mars is a prerequisite to colonization. :))

The issue is propulsive landing, and specifically rocket fire into the direction of travel at hypersonic velocity. As is often said, it's never been tried - current Mars probes are light, and therefor can slow to subsonic via parachutes. The one for curiosity was enormous even so - 52 feet in diameter.

So, unless you use some form of inflatable balutte, for a big payload, you are going to need to do some propulsive burns at supersonic velocity. This has always been a huge concern, due to both potential combustion instability in the engines induced by the unstable shockwave dynamics, and also aerodynamic stresses on the vehicle due to it becoming partially enshrouded by a varying bauble of exhaust gasses.

The main reason this is an issue is no one has ever tried it, so there's no data. At least, that was true until a few weeks ago.

SpaceX's attempt to recover the first stage included retrofire in low density hypersonic environments. They lit the some of the engines at several points on the decent.

So, we're no longer without data (Or at least, SpaceX isn't) when it comes to retrofire burns into a hypersonic environment. IMHO, this is big news when to come to Mars landing options, but I haven't seen it mentioned anywhere in that context.

I'm going to try posting this as anonymous as you suggested. If I did it wrong, please let me know.

Arizona CJ

Anonymous said...

That's a great point on the off-axis direction of Dragon thrusters. That should help.

The point about filtered sunlight is a great one. We might also want to try it in lower pressure, with a different atmospheric mix (such as high CO2).

It might also be worthwhile (and cheap) to make some simulated martian soils (Chemically similar) and see what it takes to make bricks out of it. The cement (for mortar) might be an issue, due to the low levels of calcium on mars. Just a hunch, but given the chemistry and other factors, I'm guessing that pykrite (water ice mixed with fibers, which is what they planned to make ice aircraft carriers out of in WW2, going so far as to build a prototype in a lake just outside Jasper, Alberta) will prove to be a more practical Martian building material, especially underground. It's vastly more resilient than brick, it's airtight, and keeping it frozen won't be a problem. Just line the inside walls with local-made insulation (whatever is easiest) and you've got habitable underground accommodations as big as needed, in whatever shape you like. Buried underground, it won't sublimate, even at Mars atmospheric pressures. (Well, it will, but so slowly that we're talking centuries, far longer than needed)

Arizona CJ

ken_anthony said...

Exactly my thoughts. As for bricks, the CEB should work on mars exactly as well as on earth if temperature and moisture parameter are kept at the right spec.