Help against collisions: Tiny light to make satellites identifiable
More and more satellites are orbiting the earth and identifying them is becoming more difficult. A tiny laser that flashes in a pattern could provide a remedy.
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In future, a tiny laser light could be used like a kind of license plate to ensure that satellites can be clearly identified by the earth and thus help to avoid dangerous collisions. This is the opinion of the Los Alamos National Laboratory, where the technology called ELROI (Extremely Low Resource Optical Identifier) was developed. No bigger than a thick postage stamp, the devices should flash in a specific pattern and be visible from Earth with a small telescope. The pattern should then make it easy to determine which satellite it is. Tests carried out last year showed that this works.
A small light as an identifier
As the large US research facility reminds us, there are already tens of thousands of artificial satellites orbiting the earth and it is getting fuller all the time. This increases the risk of collisions, which can trigger extremely dangerous chain reactions. This is another reason why various institutions are monitoring the objects and trying to predict possible collisions. If a danger is detected, those responsible for both satellites would be contacted so that possible countermeasures can be taken. However, this only works if it is possible to determine exactly which satellites are involved. However, this is sometimes extremely difficult.
(Image:Â LANL)
This is exactly where ELROI should help, the team writes. Satellite operators could simply attach the tiny light to the outside of their devices, where it could supply itself with energy using a small solar cell. Once in space, it would then flash in an individual pattern and be no brighter than the LEDs on any household appliances that indicate that they are switched on. However, this would be enough to see the signal with a small telescope from the Earth's surface. Thanks to the signal, it would be possible to quickly find out which satellite is being observed. This worked in two tests last year. ELROI is "cheap, tiny, self-sufficient and easy to attach", summarizes project manager David Palmer.
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What the team does not discuss in the presentation are the possible consequences for astronomy if ELROI actually becomes widely accepted. The growing number of satellites is already a major problem for astronomical research, with more and more images having to be discarded because satellites can be seen as distracting streaks. This even affects the Hubble Space Telescope. If the satellites themselves should light up in future, even if only extremely faintly, this is likely to be even more disruptive for the extremely sensitive instruments. In addition, the current interference is greatest in the evening and morning hours because the satellites reflect the sunlight. In future, the problem could persist throughout the night.
(mho)
