From: vince@offshore.ai (Vincent Cate) Newsgroups: sci.space.policy Subject: Re: JP Aerospace Airship to Orbit References: <1083293643.224485@kyle.snap.net.nz> <1083577718.392194@kyle.snap.net.nz> NNTP-Posting-Host: 207.42.133.252 Message-ID: <9186edb5.0405231945.168c8e4a@posting.google.com> "Pete Lynn" wrote in message news:<1083577718.392194@kyle.snap.net.nz>... > A "black" skin absorbing solar energy directly could > perhaps be 100C hotter than the surrounding atmosphere, imparting a > significant velocity onto impacting molecules, greater than that of > drag. Better than a solar powered scramjet. :-) If you paint the front white and the back black, there would be a net forward force. This is called the "radiometric effect". The "radiometer" was invented by Crookes a long time ago. You can see a picture of this standard toy that spins in the sun at: http://store.yahoo.com/explo/radiometer.html For slow speeds at very high altitudes this could be interesting. Looks to me like this would make the JP Aerospace airship go backwards the way they have it painted at: http://www.hobbyspace.com/AAdmin/archive/SpecialTopics/orbitalAirship.html I ordered a vacuum pump/chamber to play with this. After a few hours of searching google I decided it would be more fun, and maybe faster, to run some experiments on my own. I will post if I can figure out anything interesting. -- Vince