Session
Technical Session III: Year in Review
Abstract
The NASA Optical Communications and Sensors Demonstration program was initiated in 2012 to demonstrate optical communications from orbit at a 5 Mbps rate and demonstrate proximity operations using CubeSats. The original two spacecraft effort became a three spacecraft effort in 2015 with the first “Pathfinder” spacecraft (AeroCube OCSD-A) launched in October, 2015, to be followed by a fully-operational pair of Demonstration CubeSats (AeroCubes OCSD-B and –C) in October, 2016. The Pathfinder was flown without a propulsion system and was meant to test attitude control accuracy and a 6W, two-stage, downlink laser. Initial on-orbit checkout proceeded as planned until a software upload to the attitude control system (ACS) corrupted the boot sequence and rendered the processor inoperable. On-orbit software updates had been routine for AeroCubes for many years. This particular upload was different, and resulted in an ACS software failure. Unfortunately, the laser communications subsystem was controlled by the ACS processor and could not be turned on even to check power levels. OCSD-A is still a functional satellite, but without pointing capability. There are many new subsystems on this pathfinder that are being evaluated. This paper will provide an update on those new subsystems, specifically the OCSD-A star tracker, high-resolution camera, and the software-defined radio. It will also discuss the software error that occurred on OCSD-A, the modifications applied to the OCSD-B and –C to correct this problem, and design and testing of the steam thrusters currently planned for OCSD-B and –C.
The NASA Optical Communications and Sensor Demonstration Program: Initial Flight Results
The NASA Optical Communications and Sensors Demonstration program was initiated in 2012 to demonstrate optical communications from orbit at a 5 Mbps rate and demonstrate proximity operations using CubeSats. The original two spacecraft effort became a three spacecraft effort in 2015 with the first “Pathfinder” spacecraft (AeroCube OCSD-A) launched in October, 2015, to be followed by a fully-operational pair of Demonstration CubeSats (AeroCubes OCSD-B and –C) in October, 2016. The Pathfinder was flown without a propulsion system and was meant to test attitude control accuracy and a 6W, two-stage, downlink laser. Initial on-orbit checkout proceeded as planned until a software upload to the attitude control system (ACS) corrupted the boot sequence and rendered the processor inoperable. On-orbit software updates had been routine for AeroCubes for many years. This particular upload was different, and resulted in an ACS software failure. Unfortunately, the laser communications subsystem was controlled by the ACS processor and could not be turned on even to check power levels. OCSD-A is still a functional satellite, but without pointing capability. There are many new subsystems on this pathfinder that are being evaluated. This paper will provide an update on those new subsystems, specifically the OCSD-A star tracker, high-resolution camera, and the software-defined radio. It will also discuss the software error that occurred on OCSD-A, the modifications applied to the OCSD-B and –C to correct this problem, and design and testing of the steam thrusters currently planned for OCSD-B and –C.
