Design and Stress Analysis of Extraterrestrial ... - The Black Vault

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41
C
Fig. 5. 37.
The positive ions are extracted through the openings of 'the ionoptical
system as in the other ion motors examined above.
This motor has two appreciable advantages.
First, it is lowtemperature.
The hottest element of the ionizer, the cathode, heats
to 700-7500C if the working medium is cesium or mercury and to 550-
560 0 C if the working medium is argon. The provisional temperature
4 of the motor housing does nc", exceed 25000 in the first case, and
10000 in the second. Thus, thermal losses in this motor are minimum.
Second, the motor has the property of automatic control. With
an Increase In the temperature of the cathode, ionizatior decreases,
and with a decrease in the temperature it increases (th* ý.athode
operates on the decaying side of the characteristic in accordance
with the Langmuir curve).
586