Technologies for Formation Flight of Spacecraft

Relative Range and Attitude Sensor

Tethers Unlimited, Inc. is working under funding from DARPA to develop a RF-based system that will provide relative range and attitude determination capabilities for formations of spacecraft without requiring an external reference signal. TUI's RelNav sensor will provide relative attitude sensing to better than 1° accuracy, and range sensing between satellites to better than 10 cm accuracy.

Tethered Formations

Clusters of small spacecraft flying in formation may provide revolutionary capabilities for a wide range of applications, including interferometric astronomy for investigation of the structure of the cosmos, synthetic aperture radar for environmental studies, and military surveilance missions. Due to the nature of orbital mechanics, however, a group of satellites in orbit will tend to drift away from each other. Consequently, to hold the spacecraft in formation requires some form of propulsion. For some applications, rockets or electric thrusters for formation flying is an acceptable solution, but for many applications the propellant requirements would be prohibitive.