Sealand and Experimental Rocketry

Trei, Peter ptrei at rsasecurity.com
Wed Feb 21 07:28:22 PST 2001


> ----------
> From: 	Jim Windle[SMTP:jim_windle at eudoramail.com]
> Reply To: 	Jim Windle
> Sent: 	Wednesday, February 21, 2001 1:53 AM
> To: 	cypherpunks at 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





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