  Utilizing differential atmospheric forces in the Very Low Earth Orbits (VLEO)
regime for the control of the relative motion within a satellite formation is a
promising option as any thrusting device has tremendous effects on the mission
capacity due to the limited weight and size restrictions of small satellites.
One possible approach to increase the available control forces is to reduce the
mass of the respective satellites as well as to increase the available surface
area. However, satellites of these characteristics suffer from rapid orbital
decay and consequently have a reduced service lifetime. Therefore, achieving
higher control forces is in contradiction to achieving a minimum orbital decay
of the satellites, which currently represents one of the biggest challenges in
the VLEO regime. In this work, the geometry of a given reference satellite, a
3UCubeSat, is optimized under the consideration of different surface material
properties for differential lift and drag control applications while
simultaneously ensuring a sustained VLEO operation. Notably, not only the
consideration of sustainability but also the optimization with regard to
differential lift is new in literature. It was shown that the advantageous
geometries strongly depend on the type of gas-surface interaction and thus, two
different final designs, one for each extreme type, are presented. In both
cases, improvements in all relevant parameters could be achieved solely via
geometry adaptions.
