Value chain · CLM-0332
In plain terms
The 1978 design's steering system used 64 ion thrusters running on argon gas, grouped into eight clusters, to keep the satellite pointed correctly.
The claim as recorded
The DOE/NASA 1978 reference design's baseline attitude control system (ACS) for the 5 GW GaAlAs/CR2 photovoltaic point design uses argon-ion bombardment thrusters at a specific impulse of 13,000 seconds, arranged in eight reaction-control-system (RCS) quads, with a total of 64 thrusters across the system to provide redundancy.
Scope and limits
The ACS concept for one 1978 paper design; no argon-ion ACS of this scale has been built or flown. The thruster-life figures (5000 hr grid life, 5-yr MTBF) are design ASSUMPTIONS, not measured hardware results.
What it assumes
GaAlAs solar cells at concentration ratio 2 (CR2); the paper states the silicon (CR1) variant would need a different, unspecified thruster count.
Where it comes from
PDF p.34 (doc p.22): "The baseline ACS features an argon ion bombartment [sic] thruster reaction control system (RCS)... A total of 64 thrusters is included in the system to provide the required redundancy assuming: an annual maintenance interval, 5000 hour thruster grid lifetime and a 5-year thruster MTBF." PDF p.217 (doc p.B-15): "Figure R-11 shows an ACS employing high-performance electric thrusters, and use of the Y-POP, X-IOP orientation and inertia balancing to minimize attitude control propellants. This approach employs eight RCS quads... high specific impulse (13,000 s)... argon ion bombardment thrusters." VERIFIED by rendering both pages to PNG at 3x scale with PyMuPDF and reading the text visually; the rendered text matched the raw text layer on this occasion (no digit corruption observed for "64", "13,000", "5000", "5-year" on these two pages).
Related records
- Answers question
- QST-002 not published in this release
Cite this
energyaperture.com/c/clm-0332
CLM-0332, Energy Aperture, as of 1978.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-085
- CLM-0013The paper that modern UK studies rely on for the beam figure calls anything below 1 kilowatt per square metre safe, with 230 watts per...CLM-0020The original 1978 design set the beam at 230 watts per square metre in the middle of the receiving site, about one twenty-third of that at...CLM-0023In the 1978 reference design, two limits set the size of the transmitter and the receiving site: how much heat the transmitter can shed...CLM-0039The 1978 report set the figure to protect radio and navigation systems from a disturbed ionosphere, called the number theoretical and...CLM-0045The apparent conflict between 12 and 23 was not an error. The underlying study gave a range, and the figure adopted sits near the top of it.CLM-0101The 1978 contract required the researchers to report fixes if ionospheric disturbance pushed the pilot-beam phase error past 2 to 3...CLM-0137In four major space solar power studies from 1978 to 2007, none put a number on how much of the beam's energy would be lost if the beam...CLM-0138The original 1978 government design for beaming power down from space adds up all the expected energy losses to get 63% overall efficiency...More on the source page.