MiniCAS - A novel type of constellation acquisition systems

Kurzfassung

We present a novel type of satellite payload entitled MiniCAS (Miniaturized Constellation Acquisition System). MiniCAS will comprise an optical receiver paired with a dedicated light source. Identical sensor systems will be installed on two spacecraft. By detecting the light emitted by one spacecraft, the receiver on the distant spacecraft determines its misalignment with respect to the connecting line between the two satellites, the so-called Line of Sight (LOS). This measurement is directly related to the relative tilt of the respective spacecraft in relation to the LOS. A system like MiniCAS is essential to facilitate relative attitude control of constellations of two or more spacecraft with microradian sensitivity, potentially surpassing the achievable precision of conventional GNSS-based approaches. Naturally, MiniCAS is independent of the availability of GNSS signals, allowing for precise constellation acquisition in orbits around other celestial bodies instead of the Earth. A classic field of application is satellite gravimetry missions such as GRACE-C or NGGM (Next Generation Gravity Mission). These missions require an initial calibration of the local tilts of the two satellites with respect to the LOS to enable the establishment of an interferometric laser link. In principle, however, the MiniCAS technology offers added value wherever the relative alignment of any two spatially separated objects is of interest. We introduce the basic concept of the system as well as give an overview of the application scenarios.