Thermal Control Design for Deep Space Optical Communication (DSOC) Docking Mechanism High-Output Paraffin Actuator

Date

2023-07-16

Journal Title

Journal ISSN

Volume Title

Publisher

2023 International Conference on Environmental Systems

Abstract

Deep Space Optical Communication (DSOC) is a technology demonstration laser communication payload riding on the Psyche spacecraft that will demonstrate data transmission via laser up to 2.76 AU (probe to sun). The payload achieves fine acquisition and tracking control by utilizing Lorentz force actuators to perform dual functions: mechanical isolation from the bus to provide a stable floating platform for the optical assembly, and fine-grain pointing and tracking of the optical uplink receiver. To satisfy a Psyche requirement, during DSOC off periods, the floating platform is mechanically docked to the stationary side using a pair of Docking Mechanisms (DMs). During an optical pass the optical platform must be undocked by the DMs which each utilize a High-Output Paraffin (HOP) actuator to perform the undocking function. The DMs need to be in the undocked phase for up to 8 hours without any interruption or dithering of the HOP pin. Dithering must be prevented because this could cause disruptions to the pointing of the optical assembly. Spacecraft bus voltage on-board is static so changing the power output by varying voltage to the HOP is not possible. This is critical due to strict paraffin temperature limits; thus, a pulse-width modulation (PWM) heating scheme was developed to achieve the desired power output. This PWM was then adapted and implemented in Psyche Flight Software (FSW). The flight unit DMs were tested successfully meeting all Verification & Validation requirements using this method for all temperature and voltage ranges. The DMs have been proven to work for 8+ hours in thermal vacuum, which is required for compliance of DSOC Project Level 1 requirements. This paper describes the development of the algorithm from inception to the final Psyche flight software implementation.

Description

Rogelio Rosas, Jet Propulsion Laboratory, California Institute of Technology, USA
Kristen MacNeal, Jet Propulsion Laboratory, California Institute of Technology, USA
Marcus Wilkerson, Jet Propulsion Laboratory, California Institute of Technology, USA
Gregory Agnes, Jet Propulsion Laboratory, California Institute of Technology, USA
Joel Johnson, Jet Propulsion Laboratory, California Institute of Technology, USA
Arthur Na-Nakornpanom, Jet Propulsion Laboratory, California Institute of Technology, USA
Brenda Hernandez, Jet Propulsion Laboratory, California Institute of Technology, USA
ICES101: Spacecraft and Instrument Thermal Systems
The 52nd International Conference on Environmental Systems was held in Calgary, Canada, on 16 July 2023 through 20 July 2023.

Keywords

Deep Space Optical Communication (DSOC), docking, mechanism, High-output, paraffin, actuator, Pulse-Width Modulation (PWM), two-phase, thermal, desktop, model, modeling, Psyche

Citation