Orbital precession via cyclic pitch for the ultrasail system

UltraSail is a non-traditional approach, utilizing innovative solar sail architecture to achieve sail areas approaching 1 kin-squared. The payload resides in a central bus. Attached to this bus are several "blades" of solar sail film material that are controllable by a tip satellite at the end of each blade. This paper focuses on the dynamics and control of this UltraSail blade/tip satellite system, specifically the precession of each tip satellite/blade system. One of the biggest challenges was to develop an efficient procedure to precess the spin-axis as the UltraSail orbits about the Sun. Two methods were proposed, one using the tip satellite thrusters to precess the spin-axis, and one utilizing the solar pressure force to provide the necessary AV by pitching the blades in a cyclic manner (Cyclic Pitch). These two methods were examined and compared. A model of the blade/tip satellite system was created and simulations were performed and animated in MATLAB™. Cyclically pitching was shown to be a viable method to precess the spin-axis of the blade/tip satellite system, as well as provide considerable fuel savings over using only thrusters.