Formation flying with nanosatellites

Precision flying with several spacecraft is a major goal in space industry. Professor Michel Verhaegen and his colleagues develop numerical algorithms to enable formation flying. “By linking up several small satellites one could build huge virtual telescopes with incredible sensitivity. A dream to astronomers.”

Trade-off
“During formation flying, the satellites need to be as autonomous as possible. Communication takes time, especially if spacecraft are far apart. And communication consumes battery power that could otherwise have been used to do extra observations. The challenge is to minimize the interaction between the satellites and maximize the performance of the formation”, Verhaegen explains. “We develop algorithms for distributed control; in such a system, the satellites plan their actions based on communication with only a couple of neighbors. Fault tolerance is one of the main issues here; if a satellite fails in some way, the others will have to adapt as well as possible.”

Artificial solar eclipse
ESA is planning a mission with two spacecrafts in tight formation. This mission, Proba-3, is a proof of principle mission for high-precision formation flying. The first satellite will block the intense light from the center of the sun, simulating a solar eclipse. This enables the second satellite to study the light from the sun corona. In 2012, ESA asked Verhaegen and his team to calculate if it would be possible to reach the necessary level of precision. Verhaegen: “Proba-3 is an ambitious project, but I am sure it can be done. If this mission works out the way it should, the same technique could be used to study exoplanets. In that case you would use the first satellite to shield the intense light of the star the exoplanet is circling, to be able to detect the faint light of the planet itself.”