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NASA has successfully sent and received a message sent by a laser beam from deep space (from a distance of 16 million kilometers) – a big step towards the future of space communications. This is about 40 times farther than the Moon is from Earth.
Why was the test?
Traditionally, we use radio waves to communicate with distant spacecraft, although higher frequencies of light, such as near infrared, provide increased bandwidth and thus a huge increase in data speed. The laser test is part of NASA's Deep Space Optical Communications (DSOC) experiment, and the success of the communications link is known as “first light.” If we look at infrared radiation, its waves can easily be converted into laser form. This will not make the light move faster, but it will rearrange its beam and restrict it into a narrow channel. This requires much less energy than scattered radio waves and is much more difficult to intercept.
The use of laser technology has recently made headlines in SETI.
A new research instrument called LaserSETI developed by Elliott Gillum of the SETI Institute gives a new approach to SETI research combined with radio astronomy.
(https://www.youtube.com/watch?v=Ch3FENZKt0s)
LaserSETI is an instrument that is particularly sensitive to millisecond pulses that may have been overlooked in previous astronomical surveys using similar techniques. By exploiting monochromatism as an intrinsic property of lasers, it is possible for this type of analysis to use solid-state sensors and 2D lenses. These sensors are easy to find and are actually commercially available as video camera sensors. This Gillum device uses commercial wide-angle aperture lens cameras to cover 75 degrees of the sky. Behind the lens is a grid that turns any light source in the camera's field of view into a double rainbow-like spectrum. While the stars would produce a full spectrum from blue to red, the laser would only appear at its characteristic wavelength. The LaserSETI instrument has two identical cameras, rotated 90 degrees relative to each other along the viewing axis, allowing a double rainbow response and helping to eliminate false alarms due to cosmic rays and other potential interference. There are currently two instruments installed at the Haleakala Observatory in Hawaii, but the project involves installing at least 11 or 12 instruments in strategic locations around the world.
Italy, already an active partner of the University of Berkeley with the 65-meter radio telescope of the Cagliari Observatory, could also become a partner in the LaserSETI project, since INAF could offer one of the most desirable locations for astronomical observations. Laser observations are of the nocturnal type, so the importance of clean skies and bad weather nights are prerequisites for the success of the search. Italy has two interesting sites in the Canary Islands. The first on the island of La Palma houses the Galileo telescope ( https://www.youtube.com/watch?v=cz-R6ZC1Tk), the second on the island of Tenerife, and hosts the new Cherenkov telescope stations of the CTA network. The Canary Islands have crystal clear skies with no more than 20 days of rain a year, and are an astronomers' paradise.
https://www.youtube.com/watch?v=cz-R6ZC1Tk
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