Autonomous formation flying sensor for the Starlight Mission

A formation-flying sensor that can determine spacecraft separation with a maximum uncertainty of 2 cm, measure the bearing angles of the remote spacecraft with a maximum uncertainty of a minute of arc, and operate with a wide field of view autonomously in deep space has been designed and prototyped. It is the autonomous formation-flying (AFF) sensor that operates at 32 GHz (Ka-band) using technology similar to that of the Global Positioning System (GPS). A significant challenge lies in the simultaneous requirements for precision and a wide field of view, mandating a substantial technology development effort and design of a sensor with some novel features. Through development of a prototype, the AFF sensor has been extensively characterized and the key technology risks have been retired. It has been concluded that the AFF sensor can meet the (2-cm, 1-arcmin) requirement within the StarLight two-spacecraft stellar optical interferometer mission. An overview of the sensor design, results of the technology development, conclusions of the technology investigations, and highlights of the related inter-spacecraft issues are presented in this article.