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Collett, C. R.

Publications and source records attributed to Collett, C. R..

16 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Auxiliary propulsion system flight package

Hughes Aircraft Company developed qualified and integrated flight, a flight test Ion Auxiliary Propulsion System (IAPS), on an Air Force technology satellite. The IAPS Flight Package consists of two identical Thruster Subsystems and a Diagnostic Subsystem. Each thruster subsystem (TSS) is comprised of an 8-cm ion Thruster-Gimbal-Beam Shield Unit (TGBSU); Power Electronics Unit; Digital Controller and Interface Unit (DCIU); and Propellant Tank, Valve and Feed Unit (PTVFU) plus the requisite cables. The Diagnostic Subsystem (DSS) includes four types of sensors for measuring the effect of the ion thrusters on the spacecraft and the surrounding plasma. Flight qualifications of IAPS, prior to installation on the spacecraft, consisted of performance, vibration and thermal-vacuum testing at the unit level, and thermal-vacuum testing at the subsystem level. Mutual compatibility between IAPS and the host spacecraft was demonstrated during a series of performance and environmental tests after the IAPS Flight Package was installed on the spacecraft. After a spacecraft acoustic test, performance of the ion thrusters was reverified by removing the TGBSUs for a thorough performance test at Hughes Research Laboratories (HRL). The TGBSUs were then reinstalled on the spacecraft. The IAPS Flight Package is ready for flight testing when Shuttle flights are resumed.

Collett, C. R.↗
NASA NTRS1981

Characteristics of the LeRC/Hughes J-series 30-cm engineering model thruster

As a consequence of endurance and structural tests performed on 900-series engineering model thrusters (EMT), several modifications in design were found to be necessary for achieving performance goals. The modified thruster is known as the J-series EMT. The most important of the design modifications affect the accelerator grid, gimbal mount, cathode polepiece, and wiring harness. The paper discusses the design modifications incorporated, the condition(s) they corrected, and the characteristics of the modified thruster.

Collett, C. R.↗
NASA NTRS1978

Engineering model 8-cm thruster subsystem

An Engineering Model (EM) 8 cm Ion Thruster Propulsion Subsystem was developed for operation at a thrust level 5 mN (1.1 mlb) at a specific impulse 1 sub sp = 2667 sec with a total system input power P sub in = 165 W. The system dry mass is 15 kg with a mercury-propellant-reservoir capacity of 8.75 kg permitting uninterrupted operation for about 12,500 hr. The subsystem can be started from a dormant condition in a time less than or equal to 15 min. The thruster has a design lifetime of 20,000 hr with 10,000 startup cycles. A gimbal unit is included to provide a thrust vector deflection capability of + or - 10 degrees in any direction from the zero position. The EM subsystem development program included thruster optimization, power-supply circuit optimization and flight packaging, subsystem integration, and subsystem acceptance testing including a cyclic test of the total propulsion package.

Herron, B. G.↗
NASA NTRS1978

Engineering Model 8-cm Thruster System

Development of an Engineering Model 8-cm Mercury Ion Thruster System for Satellite Control has been successfully completed. This system operates at a specific impulse in excess of 2600 sec, produces a thrust of 5 mN with a total input power of 165 W; it has a dry mass of 16.6 kg and a mercury-propellant-reservoir capacity of 8.75 kg. This paper summarizes the development work, the system characteristics and performance, and the testing undertaken to verify the design.

Herron, B. G.↗
NASA NTRS1976

Evolution and status of the 30-cm engineering model ion thruster

In the past five years the 30-cm ion thruster has developed from infancy to maturity through the joint efforts of the NASA Lewis Research Center (LeRC) and the Hughes Research Laboratories (HRL). The evolution of the 30-cm thruster from the 200-series design to the present 900-series is described. This evolution has included both breadboard and engineering model type thrusters. The evolution description includes functional requirements, design, performance, endurance test results, and major features. The major part of the discussion centers on Hughes-built hardware although NASA LeRC contributions are reflected in the designs.

Masek, T. D.↗
NASA NTRS1976

A 10,000 hour endurance test of a 700 series 30 cm engineering model thruster

This paper describes a 10,000 hour test of the first engineering model of the 30-cm ion thruster which is expected to form the basis of future prime propulsion systems. This test demonstrated the lifetime capability of such critical components as cathodes, vaporizers, isolators, and optics. The results of the test are described including the conclusions derived from an extensive post-test analysis of the thruster. This test did identify a major life limiting problem - discharge chamber erosion. The modifications which have been incorporated in the 900 series 30-cm ion thrusters to minimize this problem are described.

Collett, C. R.↗
NASA NTRS1976

An endurance test of a 900 series 30-cm engineering model ion thruster

The 10,000 hour endurance test of the first engineering model 30-cm thruster (S/N 701) identified discharge chamber erosion as a life limiting problem. Modifications to minimize this problem have been implemented in the 900 series thrusters. This paper describes a test conducted to evaluate the success of these modifications. The post-test analysis results of thruster 701 are summarized and the erosion reducing modifications described. Test results for thruster 901 up to 4165 hours, when the test was interrupted by a shorted wire, are described. The conclusions of a post-test examination of thruster 901 are included. Also being evaluated was a thermal vacuum breadboard SCR series inverter power processor which is described.

Collett, C. R.↗
NASA NTRS1975

30 cm Engineering Model thruster design and qualification tests

Development of a 30-cm mercury electron bombardment Engineering Model ion thruster has successfully brought the thruster from the status of a laboratory experimental device to a point approaching flight readiness. This paper describes the development progress of the Engineering Model (EM) thruster in four areas: (1) design features and fabrication approaches, (2) performance verification and thruster to thruster variations, (3) structural integrity, and (4) interface definition. The design of major subassemblies, including the cathode-isolator-vaporizer (CIV), main isolator-vaporizer (MIV), neutralizer isolator-vaporizer (NIV), ion optical system, and discharge chamber/outer housing is discussed along with experimental results.

Schnelker, D. E.↗
NASA NTRS1975

A 7700 hour endurance test of a 30-cm Kaufman thruster

This paper describes an ongoing endurance test of the ion thruster which is expected to form the basis of future prime propulsion systems. The purpose of the test is to demonstrate the lifetime capability of such critical components as cathodes, vaporizers, isolators, and optics. The endurance test was preceded by development of an ion engine life test system and several intermediate duration tests. The elements of the test system are briefly described and the thruster modifications which resulted from the intermediate tests are evaluated in terms of the endurance test results. Thruster performance during the endurance test is described as well as the conclusions that can be drawn from the 8600 hours that have been completed as of March 6, 1975.

Collett, C. R.↗
NASA NTRS1973

Endurance testing of a 30-cm Kaufman thruster

Results of a program to demonstrate lifetime capability of a 30-cm Kaufman ion thruster with a 6000 hour endurance test are described. Included in the program are (1) thruster fabrication, (2) design and construction of a test console containing a transistorized high frequency power processor, and control circuits which provide unattended automatic operation of the thruster, and (3) modification of a vacuum facility to incorporate a frozen mercury collector and permit unattended operation. Four tests ranging in duration from 100 to 1100 hours have been completed. These tests and the resulting thruster modifications are described. The status of the endurance test is also presented.

Collett, C. R.↗
NASA NTRS1973

Thrust vectoring of broad ion beams for spacecraft attitude control

Thrust vectoring is shown to increase the attractiveness of ion thrusters for satellite control applications. Incorporating beam deflection into ion thrusters makes it possible to achieve attitude control without adding any thrusters. Two beam vectoring systems are described that can provide up to 10-deg beam deflection in any azimuth. Both systems have been subjected to extended life tests on a 5-cm thruster which resulted in projected life times of from 7500 to 20,000 hours.

Collett, C. R.↗
NASA NTRS1972

Development, integration, and testing of a 30 cm thruster/power conditioning and control system.

The 30 cm thruster/power conditioning and control system discussed represents a significant milestone in the evolution of prime ion propulsion systems. The effort described covers three distinct electronic hardware implementation, integration and testing phases; development of a flight-type power conditioner for laboratory testing, development of a thruster control system to control the power conditioning for demonstrating continuously variable automatic thruster throttling from a single control over a range in excess of 5:1, and finally development of an automated endurance test system incorporating many of the above designs for a 6000 hour thruster life test.

Herron, B. G.↗
NASA NTRS1969

Cesium microthruster system.

Cesium microthrustor system using beam deflection for satellite control, describing ion engine subsystem and control logic/power conditioner subsystem

Collett, C. R.↗