Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Solar super-sail could reach Mars in a month

  1. Feb 1, 2005 #1

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    http://www.newscientist.com/channel/space/mg18524846.500
     
  2. jcsd
  3. Feb 2, 2005 #2
    interesting.....
    i am thinking...... how could that spacecraft slow down when it reaches mars......
     
  4. Feb 2, 2005 #3

    Galileo

    User Avatar
    Science Advisor
    Homework Helper

    The same way I brake when skiing...

    ...**KABLAAAAMMMMMM** :rofl:
     
  5. Feb 3, 2005 #4

    saltydog

    User Avatar
    Science Advisor
    Homework Helper

    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.
     
  6. Feb 3, 2005 #5
    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..... ..
     
  7. Feb 3, 2005 #6

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    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.
     
  8. Feb 3, 2005 #7
    Good thought

    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 . !!!
     
  9. Feb 3, 2005 #8

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    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.
     
    Last edited: Feb 3, 2005
  10. Feb 3, 2005 #9
    I'm guessing this is for unmanded missions(probes) that we are currently sending out now; one way trips.

    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.
     
    Last edited by a moderator: Feb 3, 2005
  11. Feb 4, 2005 #10

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Deploy another chute or send another one ahead. The point is that this is not a momentum transfer system. It could work either way.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Solar super-sail could reach Mars in a month
  1. Solar Sailing (Replies: 7)

Loading...