US3735591A — Magneto-plasma-dynamic arc thruster

Claim 1

Independent Claim 161 words

A magneto-plasma-dynamic arc thruster of the type wherein a propellant is ionized in an arc to form a plasma exhaust beam, said thruster comprising a hollow cylindrical anode forming a chamber having an open end from which said beam is exhausted, means for injecting a propellant gas into said chamber, magnet means for forming a magnetic field through said chamber to support an electrical discharge therein, magnetic pole pieces mounted at opposite ends of said chamber for shaping the magnetic flux density of said magnetic field to direct said beam through said open end of said chamber, a cathode of a thermionic emitting material spaced from the open end of said chamber downstream thereof, and power supply means connected to said anode and said cathode for generating said arc to form said exhaust beam, said cathode being mounted in said exhaust beam whereby ions bombard said thermionic material thereby heating the same to a temperature sufficient to maintain thruster discharge current.

Claim 2

Dependent Claim 161 words

A magneto-plasma-dynamic arc thruster of the type wherein a propellant is ionized in an arc to form a plasma exhaust beam, said thruster comprising a hollow cylindrical anode forming a chamber having an open end from which said beam is exhausted, means for injecting a propellant gas into said chamber, magnet means for forming a magnetic field through said chamber to support an electrical discharge therein, magnetic pole pieces mounted at opposite ends of said chamber for shaping the magnetic flux density of said magnetic field to direct said beam through said open end of said chamber, a cathode of a thermionic emitting material spaced from the open end of said chamber downstream thereof, and power supply means connected to said anode and said cathode for generating said arc to form said exhaust beam, said cathode being mounted in said exhaust beam whereby ions bombard said thermionic material thereby heating the same to a temperature sufficient to maintain thruster discharge current.

Claim 3

Dependent Claim 36 words

An MPD arc thruster as claimed in claim 1 and including at least one hollow tube extending througH a wall of said hollow cylindrical anode for placing said chamber in communication with a supply of propellant.

Claim 4

Dependent Claim 18 words

An MPD arc thruster as claimed in claim 2 including a supply of xenon connected to said tube.

Claim 5

Dependent Claim 19 words

An MPD arc thruster of the type claimed in claim 1 including an electromagnet surrounding said hollow cylindrical chamber.

Claim 6

Dependent Claim 35 words

An MPD arc thruster as claimed in claim 4 including at least one hollow tube extending through the electromagnet and hollow cylindrical anode for placing said chamber in communication with a source of gaseous propellant.

Claim 7

Dependent Claim 62 words

An MPD arc thruster as claimed in claim 1 including a hollow magnetic pole piece mounted at the upstream end of said hollow cylindrical anode and extending into said chamber, and another magnetic pole piece positioned between said cathode and said anode, said hollow and other pole pieces establishing a pre-determined angle of divergence of the magnetic flux in the magnetic field.

Claim 8

Dependent Claim 34 words

An MPD arc thruster as claimed in claim 1 wherein the cathode comprises a hollow tube positioned along the axis of the anode downstream thereof, and means for passing propellant through said hollow tube.

Claim 9

Dependent Claim 32 words

An MPD arc thruster as claimed in claim 7 including a plate mounted in the end of said hollow tube, said plate having an orifice therein for directing propellant toward the anode.

Claim 10

Dependent Claim 96 words

In a magneto-plasma-dynamic arc thruster of the type wherein an arc ionizes a propellant to form a plasma exhaust beam, the improvement comprising means for mounting a thermionic emitting cathode in said exhaust beam downstream of an anode whereby ions bombard said cathode during thruster operation thereby heating the same to a temperature sufficient to maintain thruster discharge current, means for directing propellant through said cathode towards said anode for starting the discharge, and means for generating a high voltage wave form between the anode and the cathode to ignite said discharge thereby starting said thruster.

Claim 11

Dependent Claim 96 words

In a magneto-plasma-dynamic arc thruster of the type wherein an arc ionizes a propellant to form a plasma exhaust beam, the improvement comprising means for mounting a thermionic emitting cathode in said exhaust beam downstream of an anode whereby ions bombard said cathode during thruster operation thereby heating the same to a temperature sufficient to maintain thruster discharge current, means for directing propellant through said cathode towards said anode for starting the discharge, and means for generating a high voltage wave form between the anode and the cathode to ignite said discharge thereby starting said thruster.

Claim 12

Dependent Claim 26 words

An MPD arc thruster as claimed in claim 9 including means for forming a diverging magnetic field toward the end of said anode adjacent said cathode.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1976-05-28	1976-11-27	1977-05-29	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1980-05-28	1980-11-27	1981-05-29	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1984-05-28	1984-11-27	1985-05-29	$7700.00	Window Closed / Lapsed

Magneto-plasma-dynamic arc thruster

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag