Value chain · CLM-1073
In plain terms
A satellite flying through the beam would get a few seconds of noisy pictures and garbled data and then recover; with a hundred satellites up, one would cross a given beam about monthly; and the rectennas would have to keep fifty to a hundred and fifty kilometres from observatories, radar ranges and airports.
The claim as recorded
The programme's April 1980 findings on other satellites and on siting: LANDSAT at 704 km crossing the main beam suffers "an increase in video channel noise of 8 percent" and a modulation transfer function "decrease ... of 18 to 20 percent", its direct S-band link "a bit error rate (BER) increase of 70 to 85 percent ... during a period of about 16 seconds" and its TDRSS link "20 to 40 percent"; GPS clock and decoder jitter "in the 10 percent to 65 percent range for SPS power coupling of 10 watts to 25 watts" and S-band BER "in the range of 50 to 1,000 times" at "10 mw/cm2 to 100 mw/cm2"; star trackers "between 3 to 8 arcseconds of error" settling "in 5 to 8 seconds"; a satellite "launched due east from Cape Kennedy will not encounter the beam to a rectenna at latitude 35 unless its altitude is greater than 1000 km", one at 1200 km and 28.5 deg has "about one chance in 2000" of an encounter in its first day, and with about 100 satellites in moderate orbits "one of them will pass through the beam to a given temperate-zone rectenna about once a month", encounters lasting "up to two seconds"; and rectenna exclusion distances of "150 km for military OT&E and radio astronomy sites, 100 km for air and missile defense sites and radar astronomy facilities, 60 km for military development test ranges and ATC sites, and 50 km for nuclear and optical astronomy facilities", with mitigation restoring terrestrial systems "to the 96-100% range".
Evidence behind this: T3, test-and-analysis abstracts on LEO satellite and beam encounters and a siting abstract's exclusion distances, results still being analysed.
Scope and limits
Test-and-analysis results "still being analyzed"; Chapman's probabilities assume uncoordinated launch phase.
What it assumes
One 5 GW beam; LANDSAT and GPS as flown in 1980.
Where it comes from
PDF p.452 / printed 431, normalised: the LANDSAT sentences as quoted; "the optical aperture is the principal SPS energy coupling mode for these sensors". PDF p.453 / printed 432: the GPS and star-tracker sentences; sun sensors "less than 2 to 5 orientation change of the solar panels over a period of 1 to 1.3 seconds". PDF p.449 / printed 428: "The duration of the encounter of a small satellite with the beam can be up to two seconds"; a new SPS in transit "could take 3 to 4 seconds"; the 1000 km sentence. PDF p.450 / printed 429: the 1 in 2000 and once-a-month sentences; "Rectennas could be prohibited within 2 of the equator"; flux "at higher altitudes ... may be several hundred mW/cm2". PDF p.436 / printed 415: the separation distances and "96-100%" as quoted; "An evaluation of possible alternative frequency ranges for the SPS covers the range of 2.45-30 GHz".
Basis: per cent noise and BER change; seconds in beam; probability per day; km separations
Related records
- Answers question
- QST-017 not published in this release
Cite this
energyaperture.com/c/clm-1073
CLM-1073, Energy Aperture, as of 1980-04.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-449
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