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Summary
Overview
Benefits
Contacts
The New Millennium Program's Earth Observing-1
mission (EO-1) provides for the first on-orbit demonstration of
a low mass, low cost, dependable electromagnetic Pulse Plasma Thruster
(PPT) propulsion unit for precision attitude control.
The PPT uses solid Teflon propellant and is capable of delivering high
specific impulse (650-1400 sec), very fine impulse bits (90-1000µN-s) at
low average power (12 to 70W). The PPT consists of a coiled spring to
feed the Teflon propellant, an igniter plug to initiate a small trigger
discharge and an energy storage capacitor and electrodes. Plasma is created
by the ablation of the Teflon propellant from discharge of the storage
capacitor across the electrodes. The plasma is accelerated by Lorenz force
in the induced magnetic field to generate thrust.
The PPT is used to maintain fine pitch attitude control pointing
requirements for EO-1 while meeting stringent electromagnetic and contamination
constraints for the mission. A series of fine pitch pointing maneuvers
have been conducted with the PPT activated after the EO-1 baseline mission was completed.
The PPT is applicable
to Earth and space science missions requiring precision pointing and control.
For example, the Origins Program will require precision alignment and
coordination of multiple spacecraft. The PPT is a perfect candidate for
these types of missions, and avoids liquid propellant sloshing which could
effect instrument measurements.
Use of the PPT is particularly valuable in small spacecraft by offering
a low mass and lower cost alternative to attitude control systems requiring
reaction wheels and momentum unloading components. Also, the PPT may
be an excellent low cost and low mass alternative for conventional delta-V
propulsion systems. All of these benefits will help reduce the cost
and weight of new Earth and space science missions.
Chuck Zakrwski
NASA's Goddard Space Flight Center
Mail Code: 574
Phone: (301) 286-3392
Email: Charles.M.Zakrzwski.1@gsfc.nasa.gov
Nick Speciale
EO-1 Mission Technologist
NASA's Goddard Space Flight Center
Mail Code: 490
Phone (301) 286-8704
Email: Nicholas.J.Speciale.1@gsfc.nasa.gov
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