In sci.astro wrote:
Don Stauffer wrote in message ...
A number of deep space probes have had solar reflector attitude control
panels. These use the photons to help stabilize or move the craft to a
new attitude using the photon momentum.

Um? A number of craft have had solar power panels. Which craft
have had solar reflector attitude control?

The solar panels on Mariner 10 were used for attitude control
via radiation pressure, by tilting them appropriately between
Mercury encounters. This conserved attitude-control gas and
helped give the third flyby. See
http://nssdc.gsfc.nasa.gov/database/...g?sc=1973-085A
http://www.fukuoka-edu.ac.jp/~kanami...ar/marin10.htm

This was possible because the solar panels had to be large enough to
deliver power not only at launch but during a Venus swingby, so
there was more tolerance for off-normal pointing. In fact, the
status report at
http://www.google.com/url?sa=U&start...estern.edu/M10
indicates that the controllers had to tilt the panels on some direction
anyway for thermal control after the first Mercury encounter.

Bill Keel