The Psyche probe has opened the way for interplanetary laser communication

AccessHomo sapiens “On the Moon” was almost performed live to hundreds of millions of people in 1969. In fact, it only takes about a second for electromagnetic waves to cross the distance between the Earth and the Moon. Armstrong and Aldrin’s images could also be transmitted with enough power from our satellite to be received at relatively high speed on our blue planet, which explains why the event was broadcast on television. But every physicist knows that the intensity of an electromagnetic wave varies according to the law 1/r² From its source.

This explains why, not just a few tens of minutes to cross the distance between Earth and the Red Planet, we have never had the equivalent of a live feed of images taken by Mars rovers. The problem gets worse with planetary probes outside Mars’ orbit, as we clearly saw in the mission new Horizons When it was sometimes necessary to wait almost months of submissions, so to speak, before capturing all the information contained in some images.

Fortunately, engineers know there is a solution to this problem of declining radio transmission rates as we venture great distances from our celestial cradle: lasers.

Presentation of the experiment Optical communications in deep space (DSOC). For a fairly accurate French translation, click on the white rectangle at the bottom right. The English translation should appear next. Then click on the nut to the right of the rectangle, then on “Translations” and finally on “Translate automatically.” Select “French”. © NASA, JPL-Caltech, Arizona State University

Interplanetary communications 100 times faster?

In fact, this solution has been envisioned since the early years of the SETI Project research program. In fact, the idea that aliens might prefer to communicate over interplanetary, and even interstellar, distances using lasers is an old one. It has already been formulated before Schwartz and Townes In 1961, a year after Townes invented the laser and two years after Cocconi and Morrison Proposed the basic concept of Seti software.

In the case of terrestrial intelligence, it is estimated that the rate of transmission of information and especially images captured by interplanetary sensors could be improved by a factor of 10 to 100, or even 1000, and this is in order to develop this technology – which could thus allow us to be able to conduct an almost live broadcast of colonization Mars – where NASA embarked on an experiment called Optical communications in deep space (DSOC).

The test achieved its first success on November 14, 2023 since the Psyche probe sent data in the direction of the Hale Telescope, equipping the no less famous Palomar Observatory in California, while it was about 16 million kilometers away, almost 40 times as far away as Earth. Moon distance as described in a NASA press release (however, these data are not yet the product of observations and measurements from the Psyche probe). An infrared laser was used, and this is expected to continue for at least two years, as the probe continues its journey to the main asteroid belt between Mars and Jupiter, during which the tool used to communicate with Earth will be tested with a laser.

” Reaching first light with the instrument is one of several critical milestones for DSOC in the coming months, paving the way for higher data rate communications capable of sending scientific information, high-definition images and streaming video to support humanity’s next giant leap: sending humans to Earth. Mars said Trudy Curtis, technology demonstration manager for the Space Technology Mission Directorate at NASA Headquarters in Washington.