Monday, December 13, 2010

Apollo 13

I'd like to discuss something about that mission, which was depicted in the film starring Tom Hanks.  The thing that struck me about it was the makeshift CO2 filter that was improvised with available materials.  They had to work with what was on hand.  There wasn't any other way to deal with the problem.  What if you could formalize this process so that you can fix any kind of problem that you face?  Instead of waiting for something to be invented, improvise something with the materials that are available.

Now let me turn my attention to the problems we face in manned space missions.  If we were to apply the same process as was used in solving the CO2 problem on Apollo 13, here's what to do:  1) inventory what's available 2) brainstorm ways to use what's available that could solve the problem and 3) decide upon the best possible plan using those materials that are available.  Note that the process requires the use of what's available at the time and place in which the problem exists.  The problem can't be deferred until some other time, but must be solved in the here and now.  Now, the question:  could an effective solution be found using the technologies and techniques which we already know so that these problems can be solved?  Well, let's do a thought experiment and see.

Here's a partial inventory of what I've written about   1) space tethers,  2) recycling the external tank, and 3) a moon base.  No moon base actually exists, so perhaps that has to be deferred until later.  However, men have landed on the moon, and any landing is a temporary base.  It looks like it can't be done now, but you can get back to the moon with the rocket technology we already have, so it could be included in the inventory of proven technologies.

Alright, here's a proposal.  Launch two shuttle derived external tanks, which are already in the plans for the future.  Recycle these two external tanks and make them suitable for human habitation for a long term space presence.  In order to move these tanks to a higher orbit, use electrodynamic tethers that would provide rocketless propulsion in order to move the tanks to a higher and safer orbit.  When a lunar base has been set up, bring those lunar materials so that they could be used for this space station.  The lunar materials would come in handy in construction of the space station.   They could provide life support and radiation shielding.

Once enough material is in place the way that it is needed, things are shaping up nicely.  But, how to solve the weightless problem?  With a tether between the two tanks.  By spinning the two tanks around each other at a distance of that would enable 1g of artificial gravity, the gravity problem is solved.  The tanks would be oriented lengthwise and habitation would be stacked inside the tanks from "bottom" to "top".  The shielding would be on the sides and the stacks could provide shielding themselves.  Toward the center is where the most shielding could be in place and where the crews would spend the most time. 

Now, what if you want to move this station?  How do you provide thrust to move it to where you want?  How do you get into it and out of it?  These are questions that can be answered with the materials and technologies that are already available, I would think.

What could you do with this station?  If it could be moved to any location we want, it could be used in exploration.  Provided that the life support could be adequate for durations of up to two years, it could go to Mars as was planned in the Constellation program.  Or it could be used for mining the asteroids over a long term mission that could bring back a lot of useful stuff.

Update:
If you set up a bolo to ferry materials from the lunar surface, this can enhance the above concept.  Consider this quote from Space Tethers and Space Elevators

However, if we require continuous transportation of
cargo or astronauts between lunar base and Earth, tethers
may prove to be a superior solution.

How could this concept be used?  By setting up a modest bolo system that ferried small amounts of matter over a period of time, a significant mass could be accumulated.  Use this mass as per above and you could accumulate significant amounts of shielding and life support materials to sustain the base over long periods of time.

Now this may raise the objection that it isn't in spirit of the Apollo 13 formalized process of improvising with what is available.  However, considerable experience has been acquired in using tethers in space.  It may take extensive experimentation to get these up to speed in order to make this work, but the concept isn't far fetched.   Technically, it isn't ready yet to be included here, but it could get a lot closer if work began on it, and building upon what is already known.


Update:

I've done a trace of this idea from the first post on tethers here.  From there, I went back to Centauri Dreams, and got Paul Gilster's post on Space Tethers and Space Elevators.

This can seen as something of a reference for these ideas.  The labels for this post can give additional information.  Think of it as a kind of bibliography.  It's not formalized as one may like, but it may do.


Update:

Yes, this post is haphazard, but I keep finding things in van Pelt's book.  Here's another concept to consider in which he devoted an entire chapter: disruptive technology.  When a new technology is in its early stages of development, it is not well received nor accepted.  But over time, its advantages become disruptive and make the old established ways obsolete.  He gives two examples which I will cite in this quote:

The steamship and the car are just two examples of new technologies that dramatically disrupted the status quo, even when at the time their use did not seem to be required and their benefits seem insufficient to warrant further investments.  Space transportation now appears to be ready for a revolution as well.  Even though conventional rocket propulsion can support all we do in space and has only relatively recently reached its maturity and become trusted, the limits of its performance capabilities and economic possibilities are already in sight. 

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