Controlling the solar torque imposed on a spacecraft (10) in flight
by providing a film (52) with variable absorptive, reflective, emissive
and/or transmissive properties on the sun side of a thermal shield (50)
of the spacecraft (10). As the orientation of the thermal shield (50)
changes relative to the sun line, the absorptive, reflective, emissive and/or transmissive
properties of the shield (50) change to cause the shield's (50) center
of solar pressure to change, thus aligning it with the spacecraft (10) center
of mass (24) as viewed from the direction of the sun line. In accordance
with another embodiment of the invention, the spacecraft (100) is provided
with a plurality of control vanes (110-116) that have a variable absorptive,
transmissive, reflective and emissive property to maintain the spacecraft (100)
stably pointed towards the sun.
