February 15, 2005
Fast Boat to Mars

Dr. Benford has come up with an improvement on the solar sail.

Unexpectedly, the sail experienced a force considerably greater than predicted. They theorized that the heat from the microwave beam was causing carbon monoxide gas to escape from the sail's surface; the recoil from the escaping molecules provided what could be a useful adjunct to the propulsive force experienced by light sails.

They believe that by beaming microwave energy up from Earth to boil off volatile molecules from a specially formulated paint applied to the sail will provide enough added force to propel a spacecraft to Mars in record time.

Record time: ~1 month. Sounds good to me.

Unfortunately, the author of the article makes a small error at the end:

As science fiction readers know, this topic was explored in the 1974 novel Mote in God's Eye by Larry Niven and Jerry Pournelle. They used the idea of laser cannon from Robert L. Forward's 1961 paper Ground-Based Lasers For Propulsion In Space to bring an alien spacecraft to our solar system. Readers may also wish to explore early sf looks at solar sails.
Actually, it was the New Caledonia system (and one hopes that sail travelers to Mars wouldn't share a fate similar to the Moties).

Posted by T.L. James on February 15, 2005 08:22 PM

Comments

OK, sounds nice- how about a trip back?

Actually, I remember reading an essay by James McPhee on this subject which mentioned work done on impulse powered systems (high explosives with a blast plate- led to the Orion nuclear rocket concept). There is a note on how spraying a thin layer of oil on the blast plate appeared to protect it from blast erosion. Maybe a thin oil coat could work here, too.

Alternatively, a parabolic sail with a reflector target with silicon carbide heating element (which can also be used to turn your home microwave into a furnace), could possibly yield a high impulse drive system.

It would be neat to try out some strategies on this type of propulsion with a few dry runs to near earth asteroids.

-Rich



Posted by: Rich W. at February 20, 2005 08:33 AM

Is the spray required between impulses? If so, how do you apply it without a huge arrangement of claptrap that makes the thing impractical?

As for the silicon carbide idea, that sounds a bit more promising -- I assume you would force hydrogen or some other reaction mass through the SiC target?



Posted by: T.L. James at February 20, 2005 07:01 PM