Value chain · CLM-1083
In plain terms
Building and keeping sixty satellites was reckoned at fifty thousand working years in orbit, mostly at geosynchronous altitude where the radiation is worst; a preliminary estimate expected that a five-year career there might raise a worker's cancer risk by about an eighth, and nobody knew what heavy cosmic-ray ions would do to eyes.
The claim as recorded
The programme's first occupational-radiation estimate for its orbital workforce: "For the construction and maintenance of 60 SPS systems, each with a 30-year lifetime, it is estimated that about 50,000 man-years in space will be required ... about 90-percent of the worker-years being spent in GEO"; in GEO "the major contributor to the total dose equivalent will be the bremsstrahlung radiation from the electrons in the outer radiation belt"; solar particle events "expected to significantly increase the total dose equivalent in about 10-percent of missions of a 90-day duration"; "If a worker spends five years in space, protected by the shielding of the reference system, it is anticipated that the potential risk of having cancer may be increased about 12 percent"; heavy ions are the unknown, with mouse lenses showing that at 18 months "all mice given 10 rad showed lens opacification" after argon ions and a relative biological effectiveness "of the order 5" for argon; on weightlessness "there is no evidence that the rate of bone calcium loss diminishes or terminates during weightless exposure lasting as long as 3 months" but "All changes observed have been shown to be reversible" and "there is no compelling evidence to discourage continued lengthening of the null-gravity exposures".
Evidence behind this: T3, a preliminary occupational-radiation assessment abstract with its risk figure anticipated rather than computed, plus mouse and weightlessness abstracts.
Scope and limits
"a preliminary assessment"; no dose in rem per tour is stated in the abstract; the 12 per cent is "anticipated", not computed on the page.
What it assumes
The reference system's shielding; 90-day tours (CLM-0985).
Where it comes from
PDF p.496 / printed 475, normalised: the 50,000 man-years and 90-percent sentences; "In GEO the major contributor to the total dose equivalent will be the bremsstrahlung radiation from the electrons in the outer radiation belt"; "the HZE particles are more important in the calculations of the total dose equivalent". PDF p.497 / printed 476: the 10-percent, 150 rem, "50-100 rem" and 12 percent sentences; "The dose per mission would be expected to be a constraint on the total number of missions allowable for a space worker". PDF p.499 / printed 478: "At that time, all mice given 10 rad showed lens opacification"; "60 rad of argon radiation induces about as much opacification as 300 rads of x-rays; thus, the RBE may be of the order 5". PDF p.495 / printed 474: the bone and reversibility sentences as quoted.
Basis: man-years in space; per cent increase in cancer risk; rem; rad
Related records
- Answers question
- QST-015 not published in this release
Cite this
energyaperture.com/c/clm-1083
CLM-1083, 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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