Value chain · CLM-0331
In plain terms
Rockwell International's 1978 design study estimated the satellite would need about 93 tonnes of thruster fuel resupplied every year, a very small fraction of its roughly 30,000-tonne mass.
The claim as recorded
Rockwell International's 1978 5 GW photovoltaic point design (SRC-085 Table R-5, Appendix B) estimates annual propellant resupply for attitude control and station-keeping at 0.093 million kg per year (93,000 kg/yr), against a total satellite dry mass of 30.47 million kg (38.09 million kg including a 25% mass-growth margin).
Scope and limits
An ASSUMED design-study estimate for one 1978 point design, not measured or flown. Not representative of modern (post-2000) SPS concepts with different area-to-mass ratios.
What it assumes
1990 (from the report's perspective) baseline technology; zero launch failures; no allowance for repositioning beyond the perturbations already modelled in CLM-0330.
Where it comes from
Table R-5 "Photovoltaic Point Design Mass Statement" (PDF p.237 = doc p.B-35): "TOTAL SPS DRY WEIGHT | 30.47" [million kg], "GROWTH (25%) | 7.62", "TOTAL SPS DRY WEIGHT WITH GROWTH | 38.09", "PROPELLANT PER YEAR (W/O GROWTH) | 0.093". Confirmed by narrative text (PDF p.236 = doc p.B-34): "Total satellite mass, including a 25-percent mass growth factor, is 38.09-million kilograms. Propellant resupply for attitude control and stationkeeping is a very small annual mass compared to the satellite mass."
Basis: million kg per year, whole-satellite basis, excludes the 25% mass-growth margin
Related records
- Answers question
- QST-002 not published in this release
Cite this
energyaperture.com/c/clm-0331
CLM-0331, 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.