Monday, October 23, 2023

More ideas for space missions

I’ve done a few posts – A fun idea for a moon mission and A Space Junk Prize – about space missions I would fund if I had a few billion dollars I didn’t know what else to do with.  The point of these missions – printing bricks on the moon and putting up satellites as targets for companies to attempt to deorbit them – wouldn’t be to have some big flashy mission that gets all the news, but would do the boring groundwork to help further humanity into becoming a spacefaring civilization.  I was wondering what other missions I could think of, and this is what I came up with.

Solar shield

There is an idea, that if we can’t get enough greenhouse gases out of our atmosphere soon enough, we could put a giant mirror in space to reflect enough of the sunlight to cool the Earth.  One version is for one giant mirror, while another is for thousands of smaller mirrors working together.  My idea is a test for the second.

I figure there would be at least three small spacecraft – launched on different rockets so if there is a launch failure you can still test with two – that would each fly out to the L1 point and deploy a ten-meter shield.  Possibly, each spacecraft would have different shield materials or deploying patterns so we can test what works best.  The whole point of the test would be how these solar shields react and if we can control several spacecraft flying in close formation.  These wouldn’t be big enough to make any effect combating climate change, but if we ever needed to do this then we’d have some real-world data. 

This whole idea of climate engineering is very contentious, with some saying we need to be doing something now, to others saying we need to conduct tests so that if we do decide we need to do something we’ll have some idea of what to do, and still others saying we shouldn’t even do any tests.  As a complex issue, there isn’t a simple answer.  And if it’s any help, the data we’d get – formation flying, unfolding techniques, whatever – could easily be applied to other space activities that don’t have anything to do with climate engineering so it wouldn’t be solely a climate engineering mission.  Although that probably wouldn’t matter.

More space junk ideas

I thought of the solar shield idea, but I didn’t think that was enough for a blog.  So I wondered what else I could do, and I went back to thinking about space junk and wondered if there was another project that would help us combat that.  What I came up with would be a mission that would give us some real-world data on the smallest of space junk.

The mission would be a cubesat put into a very low orbit, one likely to only last six months or so.  This cubesat would have a telescoping rod twenty, or thirty centimeters long.  The end of this rod would be an electromagnet.  Attached to the magnet – by a small bit of metal – would be a fleck of paint one centimeter square with some design on it.  The rod would telescope out, then wait twenty or so minutes to make sure any vibration had damped out.  Then the electromagnet would be turned off and the rod retracted. 

On the cubesat would be a camera with a flash, that would take a photo every five minutes or so.  All this depends on how much memory the cubesat has and how often it can downlink the data.  The onboard computer would use the design on the fleck to figure out the distance to it and it would have tiny gas thrusters to try to stay within so many meters of the fleck.

The point of all this would be to see how flecks of paint actually interact with the near-vacuum of the upper atmosphere.  We probably don’t have much data on this.  Ideally, the cubesat could stay close enough to see if the fleck just disintegrates when the air density gets so high, if it burns up like a meteor, or if it slows down gradually enough that it just falls out of orbit.  But in reality, with the different drag between a fleck of paint and a cubesat, the cubesat might run out of fuel trying to stay close enough to see what happens.  In that case, and if the cubesat will still be in orbit for a month or two, then maybe it could be used as a target for the more aggressive methods of deorbiting satellites: ways that might cause the satellite to break up.  In higher orbits that would just make the space junk problem worse, but hopefully any debris resulting from the test would deorbit within a few weeks. 

At first, I figured such a mission could be jettisoned by a Cygnus as it was getting ready to deorbit, because I figured it wouldn’t be worth it to use a rocket to put such a small satellite into such a low orbit, but then I realized that one of the main things of science is repeating experiments to see if we get the same results.  So instead of a rocket putting one cubesat in a low orbit, it could put ten or however many will fit.  Some of these could have identical paint flecks, to see if similar things happen, or maybe thicker flecks, or maybe instead of a fleck of paint it could be a screw or some other random bit of junk the cubesat may have a better chance of staying close to.

Some would say this would just be me burning money, but hopefully we’d get some interesting data out of it.

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