Monday, October 26, 2009

NASA's "Flexable Plan"

A panel that Obama set up to review the future of NASA's manned spaceflight program goes in the right direction.

I have argued in this blog that there is no program or policy that reduces the chance of human extinction (without having evolved intelligent descendents of one form or another) more than the colonization of space. Our species is at risk as long as we have all of our eggs in one planetary basket. That risk is reduced the more we spread out.

When it comes to the colonization of space, I have argued that space itself has more to offer than the surface of any planet or moon. Mars has a surface area approximately equal to the land surface area of Earth. The Moon has a land surface area approximately equal to that of Africa. If we use the material from the asteroids to build cities in space, that material would build the surface area equivalent to 30,000 earths.

In space, you can choose your own gravity by choosing the speed at which the station rotates. You can even get different levels of gravity in the same station. On the surface of a body you get the gravity that the body gives you. Shipping costs are lower since you just give the body a nudge and it floats off towards its destination without any additional fuel. And communities can put some distance between themselves and their neighbors.

The report embraces this option through a proposed plan for future development that it called the "flexible plan". This plan is not devoted to setting up stations or even putting people on the surface of Mars or the Moon. Rather, it looks to accomplish goals in space itself.

One of these missions would include a rendezvous with and landing on an asteroid - probably an earth-crossing asteroid (the type that has the potential to hit the Earth some time in the future).

This type of mission is more like a mission to dock with a space station than a mission to land on a planet. Asteroids have so little mass (and so little gravity) that NASA would not need to worry about the costs of building expensive landers that, in turn, had the capacity to lift the astronauts back into space. Instead, the astronauts gently touch the surface and just as gently push off when they leave again.

There are currently over 600 known asteroids that are, in a sense, "closer" than the moon in terms of the amount of energy it takes to reach them. It takes more TIME to reach an asteroid and return, but less ENERGY (fuel) to do so. Some of these are no larger than a car and, as such, are poor targets. Some of these are hundreds to thousands of kilometers in diameter.

The science gained from such a mission would have significant value to the people on Earth. It would give us information on earth-crossing asteroids that threaten to do significant damage to the people of Earth.

These missions would also tell us what resources are available, floating through space in orbits that bring them near Earth. Some of these asteroids might be burned-out comets; balls of ice that now have a thick covering of dirt on the outside that keep the water tightly frozen within. Others could be pure iron.

Yet, even stone has a use in space. Space stations will need a skin that is 1 meter thick to keep out cosmic rays. These shells could be made out of anything - from the slag left over by mining - as long as it has mass. So, we are literally dealing with a resource in which every last gram of it has a use.

A related, though admittedly more ambiguous mission would be to land astronauts on one of the moons of Mars. Mars has two moons - which seem to be captured asteroids. As such, the experience we gain in landing and using the resources of an asteroid would be directly applicable.

A station built on a Martian moon would be able to run robots on the surface for purpose of studying the planet in real time. We would not need to worry about 20-minute transmissions and responses from Earth. Driving a rover on Mars from its moon would be little different from driving a rover in one's own back yard from a desktop computer. People who pilot or drive drones already have experience doing this.

Eventually, we may get people down onto the surface of Mars. The study concluded that Mars is the most interesting location (other than Earth) in the solar system. However, a landing on Mars – with the extra expense of getting people down to the bottom of a gravity well and climbing back up again – is not the best use of public money. The best use of public money is in studying a location that has significantly more potential than the surface of any planet in securing the future of humanity – space itself, and the resources for building the equivalent of 30,000 earths that are independent of any planet.


Cat's Staff said...

I have said for decades that we should not concentrate on landing people on the Moon/Mars, but make bigger space stations where we can create artificial gravity. If you watch people coming off the shuttle after they have been on the ISS for a while, you will see many need to be taken off on a stretcher. We need a way of overcoming that problem in the long run.

Also, I saw somewhere that the estimated cost of a space elevator (once certain technologies were developed) would be about $10 billion....what a bargain. We could build the ISS inside a month if we had a space elevator. There are some risks to a space elevator, but if it was put up temporarily in order to built ISS2 (a bigger, rotating, movable space station), it would be worth it.

Chris M said...

The future of human space exploration looks bleak. After making great leaps 50 years ago, stagnation has taken over. No human has left Earth orbit in 37 years, and NASA's current unambitious goals look to be further delayed or scaled back.