Value chain · CLM-1070
In plain terms
Nobody in 1980 agreed whether the ion engines' argon would be caught by the earth's magnetic field or escape: one group had most of it caught within twenty seconds, another had all but a few per cent escaping, and the third had a sixth raining back into the atmosphere.
The claim as recorded
The three April 1980 papers on the electric orbit transfer vehicle's argon exhaust disagree on where the ions go. Aerospace Corporation: the 3.5 keV beam at "130 km/sec" crosses the field at about a tenth of the Alfven speed, its momentum is "soaked up by the magneto-spheric and ionospheric plasma" through Alfven waves with a time constant "< 20 sec" and a beam length "<= 2000 km", leaving "some hot argon plasma components trapped in the magnetic field ... much like an argon ring current", and the POTV's chemical exhaust leaves "some 140 tons" of H and O atoms per flight in a shell "between 3000 km altitude and 30,000 km altitude" that "will have a very long lifetime". Goddard: plasma instabilities "are ineffective" at stopping the beam, the ion-cloud model "is not applicable", and in the beam-sheath model "all but a few percent of the beam ... escapes", the difference from the cloud model "better than an order of magnitude" in deposited energy and density. Boeing: trapped ions are lost mainly by charge exchange and for an OTV at 1.82 earth radii "only 16% of the argon precipitated". DOE's overview lists the possible consequences as enhanced trapped-electron dose, storm-like ionospheric currents "could result in long telephone line and power line circuit-breaker tripping and enhanced pipeline corrosion", and instabilities that "could cause satellite communication signal interference".
Evidence behind this: T3, three modelling abstracts on the argon exhaust's magnetospheric fate that disagree with one another, and DOE's overview of the consequences.
Scope and limits
Three models, no observation ("least-well supported by observations"); Curtis and Grebowsky reject barium releases and nuclear tests as analogues.
What it assumes
The July 1978 baseline's argon ion engines at 3.5 keV; Boeing's 1.5 kV thrusters are a different design point.
Where it comes from
PDF p.514 / printed 493, normalised: "argon ion engines of 3.5 keV beam energy, which works out to be 130 km/sec in beam speed"; "moving across the magnetic field at ~ 1/10 of the Alfven speed"; "the momentum transfer process has a time constant of < 20 sec, so the argon beam has a length of <= 2000 km"; the ring-current sentence. PDF p.515 / printed 494: POTV "ignition weight at LEO of 890 tons, of which the propellants LO2/LH2 comprise 830 tons"; "some 140 tons emitted by particular burns"; "about 1/5 of the propellants of each POTV flight would be trapped in orbits centered at about 15,000 km altitude". PDF p.522 / printed 501: "the numerous potential plasma instabilities which could take energy from the beam and hence stop it are ineffective"; "The ion cloud process yields total deposition very rapidly whereas all but a few percent of the beam in the ion beam sheath loss process escapes"; "better than an order of magnitude greater energy and number density perturbation". PDF p.523 / printed 502: "may produce sufficient scintillation to impair radio communications with geosynchronous satellites"; a Shuttle-borne test "about a kilowatt and a nozzle diameter of a few centimeters rather than a megawatt and a meter" recommended. PDF p.519 / printed 498: "One hand calculation has been made for an OTV at 1.82 earth radii. It was found that only 16% of the argon precipitated in these orbits"; PDF p.518 / printed 497: "the 920 OTV thrusters (120 cm, 1.5 kV) produce a plasma plume extending 670 km downstream". PDF p.137 / printed 114: the consequences as quoted; "The effect of POTV and COTV emissions in the magnetosphere is perhaps least-well understood at the present time and least-well supported by observations."
Basis: fraction of argon beam deposited or escaping; seconds; km; tons
Related records
- Answers question
- QST-008 not published in this release
Cite this
energyaperture.com/c/clm-1070
CLM-1070, Energy Aperture, as of 1980-04.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-449
- CLM-0964To build two of these satellites a year, about 300 tonnes of material had to arrive at the orbital construction site every day. Getting it...CLM-0974The 1978 reference design shows every loss between sunlight and the power grid as a chain of numbered boxes, and the boxes multiply out...CLM-0975Depending on which published assumptions you take, a satellite needs between about 2 and 6 square kilometres of solar blanket for every...CLM-1058The often-repeated claim that the magnetron is 188 decibels quieter than its carrier traces to a conference abstract in which the tube...CLM-1059By spring 1980 the engineers, the reviewing panel and the ionosphere experimenters were all saying the beam-intensity ceiling the whole...CLM-1060The 1980 review did not agree with itself on how much of a satellite's cost was rockets: one paper said over a third, the programme's own...CLM-1061In one 1980 volume the satellite cost anywhere from about 2,300 to 3,800 dollars a kilowatt depending on who added what - and the programme...CLM-1062In 1980 the launch vehicle that everything was costed on was said by its own designers to be arbitrarily big, and they proposed a rocket a...More on the source page.