project starshine

brixham (
Sat, 13 Jun 1998 19:34:58 +0100

Hello All,
I have a question concerning project starshine which I hope someone may be
able to answer. How visible will it be? The students have asked me, so I am
hoping someone will be able to answer the question for me.

I have asked for a mirror for the students at college to polish which will
hopefully arrive next week.

The basic information I have is that it will be a 19 inch sphere covered
with 1000      1 inch diameter mirrors, polished flat to within 10
wavelengths of light they will be
ultrasonically cleaned, put in a vacuum chamber and the unwanted thin film
of Aluminum Oxide covered up by vaporizing a mono-molecular layer of fresh
Aluminum over the top of them. Then, without breaking vacuum, a deposit of
half-wave-thick layer of Silicon Dioxide on top of the fresh Aluminum to
seal out Oxygen. 

The orbit will be 250 nautical miles at inclination of 51.6
The spacecraft's longitudinal axis will be maintained parallel to the
Earth's local magnetic field by on-board magnets, and it will be spun about
that axis by solar  pressure photon vanes that are coated to produce
alternating patterns of high and low optical absorptivity and emissivity.
Induced eddy currents in its aluminum shell will limit its spin rate to a
value of approximately one revolution every minute. 

Regards Steve Daniels
I.T. Technician
Brixham Community College
50.245N 3.34W 210ft