US3728861A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ion thruster with a combination keeper electrode and electron baffle
Assignee: National Aeronautics and Space Administration
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Filing: 1971-12-20
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Granted: 1973-04-24
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Expires: 1991-12-20
Abstract
Abstract An ion thruster is disclosed in which the cathode front end, surrounded by our insulator, is mounted flush with the front end of the flanged portion of the cathode pole piece. The thruster''s baffle positioned in front of the cathode''s front end supports the thruster''s keeper electrode which is spaced apart and directed to the cathode''s open end. The baffle is at the keeper''s electrode potential.
Inventors
- 👤 J Fletcher
- 👤 D Fitzgerald
- 👤 E Pawlik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:06
CPC Classifications
F; F03; F03H; F03H1/00; F03H1/0037; H; H01; H01J; H01J27/00; H01J27/02; H01J27/08; H01J27/14
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
170 words
In an ion thruster of the type including a main ionization chamber in which ions are formed by the electron bombardment of a vaporized propellant, with said ions exiting said chamber through a front end of said chamber, said ions further including magnetic means for providing a magnetic field in said chamber, said magnetic means including a cathode pole piece forming the back end of said chamber and having a flanged portion extending inwardly toward said chamber front end, a cathode for providing a source of electrons, a keeper electrode at a selected potential for initiating and maintaining the discharge of electrons from said cathode and an electron baffle for controlling the path of electrons entering said main chamber, the improvement comprising: first means for supporting said cathOde with the front end thereof substantially aligned with the front edge of the flanged portion of said cathode pole piece; and second means for supporting said keeper electrode and said baffle in front of said cathode end toward said main ionization chamber.
Claim 2
Dependent Claim
170 words
In an ion thruster of the type including a main ionization chamber in which ions are formed by the electron bombardment of a vaporized propellant, with said ions exiting said chamber through a front end of said chamber, said ions further including magnetic means for providing a magnetic field in said chamber, said magnetic means including a cathode pole piece forming the back end of said chamber and having a flanged portion extending inwardly toward said chamber front end, a cathode for providing a source of electrons, a keeper electrode at a selected potential for initiating and maintaining the discharge of electrons from said cathode and an electron baffle for controlling the path of electrons entering said main chamber, the improvement comprising: first means for supporting said cathOde with the front end thereof substantially aligned with the front edge of the flanged portion of said cathode pole piece; and second means for supporting said keeper electrode and said baffle in front of said cathode end toward said main ionization chamber.
Claim 3
Dependent Claim
18 words
The arrangement as recited in claim 1 wherein said baffle is at the potential of said keeper electrode.
Claim 4
Dependent Claim
50 words
The arrangement as recited in claim 2 wherein said keeper electrode is directly coupled to said baffle and said second means support said baffle so that it is in a plane perpendicular to the cathode axis and the keeper electrode is directed toward the cathode front end and spaced therefrom.
Claim 5
Dependent Claim
47 words
The arrangement as recited in claim 1 wherein said first means include an insulator surrounding said cathode at the open end thereof, and means for connecting said insulator to said flanged portion of said pole piece so that the cathode is centrally disposed in said flanged portion.
Claim 6
Dependent Claim
18 words
The arrangement as recited in claim 4 wherein said baffle is at the potential of said keeper electrode.
Claim 7
Dependent Claim
54 words
The arrangement as recited in claim 5 wherein said keeper electrode is directly coupled to said baffle and said second means include support means for supporting said baffle so that it is in a plane perpendicular to the cathode axis and the keeper electrode is directed toward the cathode front end and spaced therefrom.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-23 | 1976-10-23 | 1977-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-23 | 1980-10-23 | 1981-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-23 | 1984-10-23 | 1985-04-24 | $7700.00 | Window Closed / Lapsed |