Himangshu Kalita, University of Arizona/SpaceTREx; Leonard Vance, University of Arizona/SpaceTREx; Vishnu Reddy, University of Arizona; Jekan Thangavelautham, University of Arizona/SpaceTREx
Keywords: Lasers; space debris; spacecraft control; SSA
Abstract:
The availability of high-performance Commercial Off-The-Shelf (COTS) electronics that can withstand Low Earth Orbit conditions has opened avenue for wide deployment of CubeSats and small-satellites. Further improvement and reliability of these satellites will enable them to operate in higher orbits where they may be permanent fixtures. Not all these satellites operate as intended in space and some may face premature failure and others may become immobile. These derelict satellites if left unmanaged can become a space-debris problem. There is a need to develop secondary and backup systems to effectively move these satellites and perform traffic management of these derelict satellites so that collision risks are minimize or eliminated. Specialized spacecraft to perform moving or collecting of space debris have been suggested and all have life-limitations. In our approach, a laser beam will be used to directly communicate and control a derelict or inactive satellites and structures floating in orbit. The satellite will have a customized smart skin containing solar panels, power and control circuitry and an embedded secondary propulsion unit. A secondary propulsion unit may include electrospray propulsion, solar radiation pressure-based system, photonic laser thrusters and Lorentz force thrusters. Solar panels typically occupy the largest surface area on an earth orbiting satellite. Furthermore, our previous work has shown that commercial space-grade solar panels can be used to detect and distinguish blue and purple laser beams even when exposed to sunlight. A laser beam from another spacecraft or from the ground would interact with solar panels of the derelict spacecraft. The laser beam would be used to communicate a move which would then trigger operation of the secondary propulsion unit. The laser beam maybe used to guide the movement of the spacecraft, trigger impulse maneuver commands, perform attitude control maneuvers and corrections. Ground and/or space surveillance would be used for verification, to start and stop movement, perform corrections and other such maneuvers. The entire move maneuver would be made possible without operation of the Command and Data Handling Computer onboard the derelict satellite. Thus, the laser beam from ground would act as a remote control for the spacecraft. Use of a laser beam to perform this external control has several important advantages. A laser beam enables secure point to point communication and cannot be eavesdropped, unless if the eavesdropping unit is in the way or close to the derelict satellite. Both scenarios can be used to determine if an eavesdropping unit exists. However, if RF (Radio Frequency) were to be used, then eavesdropping maybe possible without detection. RF signal requires licensing and is congested due to high demand. Use of a laser beam avoids these logistical challenges. This laser system may serve as a secure backup system that can be used to mitigate and take back control of a satellite from cybersecurity threats/hacking using RF communication. A laser beam generated from the ground has the advantage of being extensible, with new and advanced optics, higher power transmission and high data frequency. Ground operation of the laser combined with ground surveillance offers a low-cost, secure approach to operate, keep track of and station-keep spacecraft and structures in space.
Date of Conference: September 11-14, 2018
Track: Poster