Spacecraft high-voltage power supply construction, https://ntrs.nasa.gov/citations/19750015780
The following was attached to a sounding rocket?
The 100 kV, 5 uA supply shown in Figures 55 through 58 was designed as
a Cockroft-Walton device contained within a vessel pressurized to 15
psig with SF6
Travelling wave tubes frequently used as a microwave amplifier for spacecrafts need a high voltage supply. TWTs with about 10 W output power typicaly used 3 kV 30 mA supplies. 3 kV 30 mA is 90 W DC input power, about 11 % efficiency.
Source : http://www.r-type.org/articles/art-030.htm
L3Harris company claims to have built 3,203 TWTs in orbit, operating for ...
Linear accelerators have been employed in space. While "voltage" is perhaps not the right term, precisely, these do generate very high energy beams, and frequently using means (like RF, etc) other than direct acceleration by a high voltage DC supply.
There are current proposals to develop a 1MeV RF linac for experiments in space. Early ...
The Space Tether Experiment in 1996 induced a current by dragging a conducting tether behind the Space Shuttle (and, thus, through the Earth's magnetic field). It generated 3500 volts before snapping off due to a manufacturing defect.
For more about how this works in general see this answer.
For more about the ...
Potential answer (pun intended): 8000 volts for the Apollo television cameras.
Several voltage levels must be accounted for: as much as 8 kilovolts are required at the tube photocathode, and various voltages up to 600 volts are required at the base.
Apollo Experience Report: Television System, NASA Tech Note D-7476, p. 18
No. According to page 221 of NASA's 1998 report TM-98-206956/VOL1, Living Together in Space: The Design and Operation
of the Life Support Systems on the International
Space Station (page 255 of the pdf file),
a 28 Vdc brush-type motor ... 14.85 W peak
drives the relief valve of ISS's Positive Pressure Relief Assembly (PPRA).