LAST: Laser Array Space Telescope

A phased array operates by modulating the phases of several signals, allowing electronic control over the locations that these signals interfere constructively or destructively, allowing the beam to be steered. A space-based laser phased array, called the Directed Energy System for Targeting of Asteroids and exploRation (DE-STAR) has previously been posited by our group for a number of uses, from planetary defense to relativistic propulsion of small probes. Here we propose using the same basic system topology as a receiver rather than a transmitter. All of the components in the system, excluding the laser, are bidirectional. Rather than each elements transmitting laser light, they would instead receive light, which will then be combined to create an interference pattern that can be imaged onto a focal plane. The Laser Array Space Telescope (LAST) uses most of the same components and metrology as DE-STAR and could thus be integrated into a singular system, allowing both transmit and receive modes. This paper discusses the possible applications of this system from laser communications to astrophysics.