Solar super-sail could reach Mars in a month

  • #1
Ivan Seeking
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Gregory Benford of the University of California, Irvine, and his brother James, who runs aerospace research firm Microwave Sciences in Lafayette, California, envisage beaming microwave energy up from Earth to boil off volatile molecules from a specially formulated paint applied to the sail. The recoil of the molecules as they streamed off the sail would give it a significant kick that would help the craft on its way. "It's a different way of thinking about propulsion," Gregory Benford says. "We leave the engine on the ground." [continued]
http://www.newscientist.com/channel/space/mg18524846.500
 

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  • #2
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interesting.....
i am thinking...... how could that spacecraft slow down when it reaches mars......
 
  • #3
Galileo
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vincentchan said:
interesting.....
i am thinking...... how could that spacecraft slow down when it reaches mars......
The same way I brake when skiing...

...**KABLAAAAMMMMMM** :rofl:
 
  • #4
saltydog
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vincentchan said:
interesting.....
i am thinking...... how could that spacecraft slow down when it reaches mars......
Isn't that a problem in general with very high speeds? I recall reading (somewhere), even if we do develop systems which reach a good percent of the speed of light, slowing down would take a long time.
 
  • #5
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Isn't that a problem in general with very high speeds? I recall reading (somewhere), even if we do develop systems which reach a good percent of the speed of light, slowing down would take a long time.
It is not only time.... since the spacecraft has no engine, where is the slow down power came from :tongue2:

The power slowing down the spacecraft is comparable to that of speeding it up if the speed is high..... ..
 
  • #6
Ivan Seeking
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Assuming that the microwaves could penetrate the sail, they could just turn around to slow down. The paint would boil off in the other direction.
 
  • #7
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Good thought

vincentchan said:
interesting.....
i am thinking...... how could that spacecraft slow down when it reaches mars......
But that does not preclude a braking system , but it does mean that it has to be carried as part of the whole. Unfortunately ( there appears no braking mechanism other than burning fuel ) so the faster you go the more fuel you would have to carry , and God only knows what you would do if you wished to return. Cause now the solar wind is agin you , OOOOps . !!!
 
  • #8
Ivan Seeking
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The sail could work both ways. The energy to momentum ratio of EM is higher than that of ejected mass. Since energy from the microwaves causes the paint to boil off as mass, and not as radiant energy, the momentums do not cancel.
 
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  • #9
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rayjohn01 said:
and God only knows what you would do if you wished to return. Cause now the solar wind is agin you , OOOOps . !!!
I'm guessing this is for unmanded missions(probes) that we are currently sending out now; one way trips.

Ivan Seeking said:
Assuming that the microwaves could penetrate the sail, they could just turn around to slow down. The paint would boil off in the other direction.
Ideally all the paint would boil away, leaving a micrometre-thin sail to continue the voyage to Mars.
They don't want any paint left over after they "shoot" the microwaves at the sail, so there wouldn't be any left to slow it down that way.
 
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  • #10
Ivan Seeking
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Deploy another chute or send another one ahead. The point is that this is not a momentum transfer system. It could work either way.
 

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