Project West Ford was an experiment carried out by the United States in the early 1960s. The plan was to place a large number of dipoles (small copper needles) into Earth orbit for use in relaying military communications. The dipoles would form a belt of radio-reflecting antennas - in effect creating an artificial ionosphere. Every aspect of the project represented new technology at that time.
The experiment was designed to ensure that the dipoles would only remain in orbit for a few years. They were given a high area-to-mass ratio so that pressure from solar radiation acting on them would gradually distort their circular orbits into highly elliptical ones. Eventually they would dip to an altitude at which air resistance would sweep them out of orbit and they would be destroyed in the atmosphere.
Concerns were expressed from other countries about interference with optical and radio astronomy, and potential dangers to other satellites and manned space flights, but the experiment went ahead.
On 21 October 1961 Air Force Atlas-Agena B carried into orbit a cylinder containing 75 pounds of dipoles embedded in naphthalene (which would evaporate in a vacuum). The cylinder was to rotate and centrifugal force would cause the dipoles to exit the cylinder and form a thin orbital ring. However, there was a malfunction and the dipoles did not disperse, instead forming small clumps.
A modified experiment was launched on 9 May 1963. This time all went well and a dipole belt was established. Over the next few years voice, data, and teletype were regularly transmitted between the West Ford stations at Millstone Hill in Massachusetts and Camp Parks in northern California.
Despite the success of the experiment it was not repeated. Technology had moved on and satellites were used for communications instead.
Although the dipoles in the second experiment were removed from orbit within a few years as planned, some of the dipoles from the first still remain in orbit as space debris. There are estimated to be roughly 750,000 dipoles spread over 40,000 clusters, with a total mass of 60g.
This sounds terrible but is actually only a tiny contribution to the ‘space junk’ issue.
As of 31 July 2026 there are estimated to be 54,000 space objects greater than 10 cm (including approximately 9300 active payloads), 1.2 million space debris objects from greater than 1 cm to 10 cm, and 140 million space debris objects greater than 1 mm to 1 cm - making a total mass of all space objects in Earth orbit of more than 17,000 tonnes.
all rights reserved by Slightly Washed Out Goth
https://www.cia.gov/readingroom/docs/CIA-RDP66R00638R000100150083-6.pdf
https://www.ll.mit.edu/sites/default/files/page/doc/2018-05/Looking_Back_3.pdf
https://airandspace.si.edu/collection-objects/communications-satellite-west-ford-dipole-dispenser/nasm_A20040113000
https://conference.sdo.esoc.esa.int/proceedings/sdc3/paper/90/SDC3-paper90.pdf
https://commons.wikimedia.org/wiki/File:Westford_dipole_dispenser_%2B_canister,_Udvar-Hazy_Center.jpg
https://sdup.esoc.esa.int/discosweb/statistics/
 |
| European Space Agency https://en.wikipedia.org/wiki/File:Satellite_break-up_ESA375611.jpg |
Comments
Post a Comment