Andrew Sinclair, associate professor of aerospace engineering, is studying the relative motion dynamics of satellite formations in elliptical orbits. Sinclair, along with Ryan E. Sherrill, aerospace engineering ’13, has been working in collaboration with faculty member Subhash Sinha in the Department of Mechanical Engineering and Auburn alumnus Alan Lovell, aerospace engineering ’01, a research aerospace engineer at the Air Force Research Laboratory in New Mexico. The team’s research on formation flying dynamics is critical to developing next-generation space vehicle design, which will require vehicles to perform operations such as rendezvous, on-orbit servicing and orbital debris removal.

While these dynamics are well researched in circular orbits, Sinclair’s work focuses on elliptical orbits, which could provide new insight to both mission planners and satellite operators. In circular orbits, the motion of one satellite relative to another is described by Hill-Clohessy-Wiltshire equations. Sinclair and Sherrill, along with Sinha and Lovell, have developed time-varying coordinate transformations that reveal how the Hill-Clohessy-Wiltshire equations actually generalize to elliptic orbits. Their work is improving the visualization of relative motion in elliptical orbits, and is leading to fuel efficient approaches to formation control.