Power plants – Reaction motor – Electric – nuclear – or radiated energy fluid heating means
Reexamination Certificate
1999-06-11
2001-08-07
Thorpe, Timothy S. (Department: 3746)
Power plants
Reaction motor
Electric, nuclear, or radiated energy fluid heating means
Reexamination Certificate
active
06269629
ABSTRACT:
BACKGROUND OF THE INVENTION
There is a need for improved plasma thrusters for attitude control, station-keeping, and primary propulsion of very small satellites in space such as “Microsats” weighing less than 20 kg and “Nanosats” weighing less than one kg. These small satellites are expected to be widely used for Air Force and commercial applications. Such attitude control thrusters should be packaged in small lightweight containers and be highly efficient so as to employ small amounts of energy, typically about one watt. Relative to standard sized satellite thrusters, such small pulsed plasma thrusters (PPT), having 10-100 size reductions, should eliminate the prior art PPT which require separate spark plug igniter devices, in favor of lightweight components permitting precise control of a number of small impulse propellant modules, by means of a single electrical pulser for selectively actuating desired propellant impulse producing modules via a plurality of transmission lines.
It is desired to provide a reduction of attitude control system (ACS) thruster mass by ninety percent or more, obtained by eliminating conventional torque rods or reaction wheels, in accordance with the placement of lightweight low cost propellant modules at the corners of the spacecraft, each module independently and selectively controlled by a single low mass centrally located pulse generating thruster control device which can employ an energy storage capacitor. Also, the arrangement has none of the aforesaid prior art spark plug igniters. The use of standard, readily available components, such as those previously flight qualified, is also desired.
SUMMARY A PREFERRED EMBODIMENT OF THE INVENTION
The aforesaid needs are met by providing a precisely controlled microPPT, e.g. one watt, producing small reproducible impulse bits of thrust by means of a plurality of coaxial cable propellant modules, providing increased thrust for a small fixed discharge energy, which reduces the volume required to store the propellant mass and which decreases radiated electromagnetic interference (EMI) relative to prior thrusters. More specifically, each propellant module, which can be positioned at a selected outer portion of the satellite, comprises a semi-rigid section of an ordinary low cost coaxial cable. High voltage pulses, initiated by a charged energy storage capacitor of a thruster control pulse generator, are selectively impressed or discharged across the outer conductive cylindrical wall of an ordinary coaxial cable segment of each propellant module and its inner central conductor, to produce vaporization of the solid “TEFLON” polymer spacer or filler, separating the inner and outer conductors, and in turn generating small precise impulse forces oriented to permit easy attitude satellite control. The result is a lightweight PPT having no sparkplug igniter, and using significantly less propellant to perform a given small satellite maneuver than alternative designs such as cold gas thrusters and those using thermal acceleration. Changing the capacitor discharge frequency and thus the frequency of the resulting pulse train applied across the coax components can also be used to change the degree of thrust.
REFERENCES:
patent: 4548033 (1985-10-01), Cann
patent: 5924278 (1999-07-01), Burton et al.
Rodriguez William
Stover Thomas C.
The United States of America as represented by the Secretary of
Thorpe Timothy S.
LandOfFree
Micro-pulsed plasma thruster having coaxial cable segment... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Micro-pulsed plasma thruster having coaxial cable segment..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Micro-pulsed plasma thruster having coaxial cable segment... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2485370