---------- From: Jim Windle[SMTP:jim_windle@eudoramail.com] Reply To: Jim Windle Sent: Wednesday, February 21, 2001 1:53 AM To: cypherpunks@einstein.ssz.com Subject: CDR: Re: Sealand and Experimental Rocketry

I think Tim's point was simply that Sealand's location is too far north to be a good launch site. To put a useful satellite in an orbit with a useful footprint for this purpose from a launch site so far north would require a lot lift capacity eliminating small launch systems, raising the issue of Sealand's ability to support the launch infrastructure. It would probably also mean launching to the east over highly populated areas in the EC which would probably object to the launch as well. --

See:

http://www.stanford.edu/dept/news/report/news/january31/opal-a.html

Launching these amateur sats costs about $50k (http://www.osss.com/), but there are buts Biggest is: You're only getting to LEO - about 500 miles up. Any given LEO satellite is visible from a given spot only for short periods every few days (see any of the sites giving spotting times for the ISS for examples). Thus, the services of a sat are only occasionally available. Getting to geosynchronous orbit is much more expensive, and requires a satellite with much more sensitive antenna and more powerful transmitters (you're about 50x are far away). Even then, you'd need at least 3 sats to get continuous coverage. Rabin's scheme requires (even given the the unobtanium-like nature of a trustworthy third party terabit/s true randomness source) that both Alice and Bob be able to key into the bitstream at the same 'time'. At very least they have to see the same sat at the same time, and even then their different (and changing as the sat moves) distances from the sat make getting crypto sync challenging (to say the least). If we really had a trustworthy 3rd party, there are lots of other more practical protocols we could use. Peter Trei