Engineering topics

Palumbo, D. J.

Publications and source records attributed to Palumbo, D. J..

3 records

NASA NTRS1976

Pulsed plasma propulsion system for North-South stationkeeping

A completely integrated pulsed plasma propulsion system for North-South stationkeeping has been developed. System testing on a thrust balance has provided following new results: (1) A simple, helically coiled, spring-fed propellant subsystem for 38,284 lb-s (166,000 N-S) total impulse is feasible; (2) The propulsive performance level is compatible with North-South stationkeeping requirements; (3) Power conditioning is as simple as that of the space flight proven microthruster system; (4) Vacuum compatible, high energy density capacitors (40 joules/lb) capacitors have been developed and tested as part of the system; (5) 10,000 lb-sec of total impulse has been generated. Future improvements will include reducing electrode erosion, improving the structural rigidity of the assembly and continuously operating the system until 37,000 lb-sec of total impulse have been generated.

Guman, W. J.↗

NASA NTRS1972

Continuing development of the short-pulsed ablative space propulsion system.

Major advancements have been made in solid propellant pulsed plasma propulsion technology. A LES-6 microthruster has operated for 8900 hours in orbit. Millipound thrustors have been developed and tested at performance levels of as low as 112 watts/mlb. Efficiencies of up to 50% and specific impulse values up to 5000 sec have been measured. An improved microthrustor has operated at 207 watts/mlb continuously for 1440 hours. Correlations of design and performance data exist to allow thrustors to be built to meet a particular level of performance.

Palumbo, D. J.↗

NASA NTRS1972

Propellant sidefeed-short pulse discharge thruster studies

The technique of feeding a solid propellant into the discharge from the sides of the discharge was evaluated. The thrust/power ratio could be significantly effected by the included angle of V-shaped propellants and by the electrode length. This result implies that when results are compared at the same specific impulse it is possible to obtain higher thrust efficiencies. In particular, it was found that for a given discharge energy the thrust/power ratio correlated with propellant mass. Increasing the integral simultaneously increases both the gas dynamic and electromagnetic thrust. An analytic expression was formulated for ablated mass which comprehensively describes experimental data in terms of geometry and electrical parameters. The correlation of the product impulse x specific impulse with discharge energy was also described. It is suggested that the reliability of dry energy storage capacitors does not equal the reliability of liquid impregnated units when the comparison is made at the same joules/Kg rating.

Palumbo, D. J.↗