NASA is conducting efforts to evaluate high-power hydrogen arcjets for orbit transfer propulsion applications. As part of this program, an attempt was made to reexamine both radiatively- and regeneratively-cooled, 30 kW thrusters first demonstrated by the Giannini Scientific Corp. in 1963. The arcjets were configured to force arc attachment upstream of the throat in a subsonic chamber region. While thruster currents were steady, the voltage traces exhibited sawtooth waveforms at frequencies on the order of 20 kHz. Voltage variations per cycle were typically between 100 and 310 volts, indicating major changes in the position of the arc attachment with time. When operated at their respective design points, the performance of both thrusters fell below the values listed in the 1960's development reports. The reason for the discrepancies is not currently understood and further investigations are in progress. However, the recently measured efficiencies were high compared to those obtained with constricted-arc designs at similar conditions, and further arcjet performance optimizations may be possible.
[1]
T. Miller.
Systems analysis for an operational EOTV
,
1991
.
[2]
R. E. Sheets,et al.
Development of a regeneratively cooled 30-kw arcjet engine
,
1964
.
[3]
Luis R. Pinero,et al.
The 10 kW power electronics for hydrogen arcjets
,
1992
.
[4]
John M. Sankovic,et al.
Performance of a low-power subsonic-arc-attachment arcjet thruster
,
1993
.
[5]
Francis M. Curran,et al.
High-power hydrogen arcjet performance
,
1991
.
[6]
John R. Brophy,et al.
The design and operating characteristics of a 30-kW thermal arcjet engine for space propulsion
,
1986
.