Re:Three strikes and you're *out*...
by
Rei
·
· Score: 5, Interesting
It depends. How thin you can make the solar sail is of critical importance. For example, a 12 micron solar sail will be superior to chemical rockets, mass-wise, for missions of longer than 2 months, and superior to ion drives for missions longer than two years. A one micron solar sail, however, will become superior to chemical rockets in just over five days, and ion drives in two months. I have some issues with their calculations (they assume constant solar flux, for example), but it still drives home how, if you can get a very thin sail, your accelerations can be incredible. Also, at least in theory, they'll be cheap to produce and difficult to have just fail on you. Not that I don't like the concept of M2P2;)
For comparison, Cosmos 1's sail is 5 microns (although it's not designed to be permanent). I was thinking the other night about a possibility (who knows if it is realistic). You could produce your sail in three layers:
1) A heavy, strong, flexible backing a dozen or so microns thick that will erode with sun exposure
2) A thin, durable, structurally weak layer less than a micron thick
3) An atomic-scale coating of aluminum
Of course, at regular intervals, you'd have to lay down a thick durable layer to keep the structure from tearing. The reasoning behind my idea is that you can create, stow, and deploy the sail in a heavy, durable fashion; however, once it has been in space for a few days/weeks, it becomes incredibly lightweight from solar exposure (but doesn't tear because it is no longer experiencing any significant forces beyond the uniform solar radiation pressure). You would unfurl with the heavy backing to the sun, and only switch to the aluminized side once the craft has lost mass.
-- The War of 1812... the good 'ol days when the federal government actually tried to save New Orleans.
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It depends. How thin you can make the solar sail is of critical importance. For example, a 12 micron solar sail will be superior to chemical rockets, mass-wise, for missions of longer than 2 months, and superior to ion drives for missions longer than two years. A one micron solar sail, however, will become superior to chemical rockets in just over five days, and ion drives in two months. I have some issues with their calculations (they assume constant solar flux, for example), but it still drives home how, if you can get a very thin sail, your accelerations can be incredible. Also, at least in theory, they'll be cheap to produce and difficult to have just fail on you. Not that I don't like the concept of M2P2 ;)
For comparison, Cosmos 1's sail is 5 microns (although it's not designed to be permanent). I was thinking the other night about a possibility (who knows if it is realistic). You could produce your sail in three layers:
1) A heavy, strong, flexible backing a dozen or so microns thick that will erode with sun exposure
2) A thin, durable, structurally weak layer less than a micron thick
3) An atomic-scale coating of aluminum
Of course, at regular intervals, you'd have to lay down a thick durable layer to keep the structure from tearing. The reasoning behind my idea is that you can create, stow, and deploy the sail in a heavy, durable fashion; however, once it has been in space for a few days/weeks, it becomes incredibly lightweight from solar exposure (but doesn't tear because it is no longer experiencing any significant forces beyond the uniform solar radiation pressure). You would unfurl with the heavy backing to the sun, and only switch to the aluminized side once the craft has lost mass.
The War of 1812... the good 'ol days when the federal government actually tried to save New Orleans.