Tuesday, June 4, 2013
Caltech/JPL Association for Gravitational-Wave Research Seminar
Micropropulsion Applications from Gravity-Wave Telescopes to Exoplanet Observatories and Cube-Sats
John Ziemer, Jet Propulsion Laboratory
(with Juergen Mueller, Colleen Marrese-Reading, and Richard Hofer)
Micropropulsion systems fall into two categories: systems that provide precision thrust at micronewton levels for ultra-stable pointing and scaled-down, compact propulsion systems for small spacecraft. Both types of micropropulsion systems have their own challenges and development issues. This talk will highlight those challenges and provide examples of flight systems for both applications.
JPL has delivered two flight-qualified Colloid Micro-Newton Thruster (CMNT) systems to the European Space Agency (ESA) for a flight demonstration on LISA Pathfinder. The CMNTs will provide precise spacecraft control for the drag-free technology demonstration mission, Space Technology 7 (ST7). The ST7 mission is sponsored by the NASA New Millennium Program and will demonstrate precision formation flying technologies for future missions such as the LISA. The ST7 disturbance reduction system (DRS) will be part of the ESA LISA Pathfinder mission using the European gravitational reference sensor (GRS), part of the LISA Technology Package (LTP). To achieve the nanometer-level precision control requirements, each of eight thruster systems is required to provide thrust between 5 and 30 μN with resolution ≤0.1 μN and thrust noise ≤0.1 μN/√Hz. Developed by Busek Co. Inc., with support from JPL in design and testing, the CMNT has been developed over the last six years into a flight-ready and flight-qualified microthruster system, the first of its kind. The first half of the talk will describe this flight hardware development activity.
In the past JPL has also developed small and micro-sized gas-fed pulsed plasma thrusters, ion engines, vaporizing liquid microthrusters, vacuum arc thrusters, and laser ablation thrusters. Outside of JPL, teams have developed extension propulsion capabilities for small-, micro-, and even nano-spacecraft, including cube-sats. This second half of the talk will describe some of these systems and future directions for micropropulsion.