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.