Value chain · CLM-1014
In plain terms
The 1980 programme did the sums on what four hundred heavy launches a year would do to the upper air: a lot more water high up, a big local rise in nitric oxide from re-entries, and an ozone change too small to measure either way. Its own two volumes disagree by five times on the ozone offset from re-entry, and the later one expected the sign to flip.
The claim as recorded
For 375 to 400 HLLV flights per year on methane/LOX first and hydrogen/LOX second stages, the DOE 1980 assessments compute upper-atmosphere water increases of about 0.4 per cent at 30 km and 8 per cent at 80 km globally (up to 15 per cent at the 30 deg N launch latitude, and a factor of 100 to 150 above 120 km), 60-70 t of NO per second-stage reentry raising mesospheric NO by about 40 per cent at 75 km between 20 and 30 deg N, CO2 at 1-2 parts in 10^5 (375 flights equal to 23 per cent of one 1000-MW coal plant), sulphur dioxide of about 300 t/yr against a natural 200,000 t/yr, and an ozone-column change of -0.01 to -0.02 per cent from exhaust with a reentry-NO offset stated as +0.1 per cent in the August summary but +0.02 per cent in the November detailed volume, which adds that revised rate coefficients would turn "the smaller ozone gain" into "a small ozone loss"; every ozone figure is described as undetectable, and the detailed volume says "with few exceptions, the results should be regarded as tentative".
Evidence behind this: T3, the programme's summary and detailed atmospheric volumes, which disagree by a factor of five on one figure.
Scope and limits
Propellants are methane and hydrogen; the models carry no black carbon, alumina or chlorine, which are the species the modern LCAs (CLM-0837, CLM-0855) identify as dominant for kerosene and solid-motor fleets. The 1980 figures therefore do not transfer to any 2020s launch vehicle and may not be used to size or discount the modern exclusion. The +0.1 vs +0.02 discrepancy is not explained by either volume. SRC-529 p.76 (printed 66) also gives its one-dimensional result as "0.001-0.01%" (carried in support), so the summary volume's own range brackets the detailed volume's +0.02 per cent from below; the 5x disagreement is between SRC-529's two-dimensional +0.1 and SRC-535's +0.02.
What it assumes
The 1978 Reference System vehicle set and propellants; 1980 one- and two-dimensional photochemical models.
Where it comes from
p.74 / 64: "approximately 0.4% at 30 km and 8% at 80 km altitude, based on an assumed 400 HLLV flights per year ... at 80 km reaches a maximum at the assumed launch latitude (30 deg N) of approximately 15%". p.75 / 65: "An estimated 60-70 t of NO would be generated by frictional heating during the reentry of a single HLLV second stage ... at 75 km ... would increase the NO concentration by about 40% between 20 deg N and 30 deg N latitude, and by approximately 10% at 10 deg N and 40 deg N". p.76 / 66: "decrease the total globally averaged ozone column by about 0.01% ... reentry-generated NO ... would be to increase the total ozone column by about 0.1% on a global average basis ... This estimate is quite uncertain ... one-dimensional model ... 0.001-0.01% ... all model calculations made to date yield values that would be undetectable"; "about 300 t/yr of sulfur dioxide into the stratosphere ... about 200,000 t/yr due to oxidation of carbonyl sulfide". SRC-535 p.65 / 55: "approximately -0.015%, globally averaged ... The effect of NO deposition owing to reentry of the HLLV second stage on the ozone column is an increase by about 0.02%, globally averaged ... The smaller ozone gain is expected to become a small ozone loss (Whitten, private communication, Aug. 1980)"; Fig. 19: "0.022 % (AUTUMN) 0.021 % (SUMMER)". p.7 / vi: "1-2 parts per 10^5". p.56 / 46: "375 HLLV launches would amount to only 23% of the quantity produced by a typical 1000-MW, coal-fired power plant"; "above 120 km is an increase of approximately a factor of 130-150". p.106 / 98: "with few exceptions, the results should be regarded as tentative". SRC-534 p.39 / 37: "0.01 to 0.02% decrease ... An independent study (14) estimated a decrease of 0.03% ... National Academy of Sciences' study (12) ... ozone may be reduced by about 8% during the next 30 years." All render read. The degree sign is printed; "deg" is ASCII substitution.
Basis: per cent change in concentration or ozone column; t/yr
Related records
- Answers question
- QST-008 not published in this release
Cite this
energyaperture.com/c/clm-1014
CLM-1014, Energy Aperture, as of 1980.
Connected records
Other published records linked to this one. A list, not a judgement.
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- Also from SRC-535
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