Record bandwidth in space: data received at 25 Mbit/s from 226 million km away

After last December’s record, the DOSC experimental optical communication system on board the Psyche probe has achieved a new record: data was downloaded at a speed of 25 Megabit/s from a distance of 226 million km, equal to one and a half times the distance between the Sun and the Earth. This is an important milestone, because that distance is comparable to that between Earth and a hypothetical outpost on Mars. The aim of the Deep Space Optical Communications technical demonstration (the module covered with gold foil in the image above) is in fact to verify the performance of an optical communication system based on LASER, capable of offering from 10 to 100 times more bandwidth compared to current radio communications, which could become critical in supporting the first astronauts on Mars.

NASA’s Jet Propulsion Laboratory engineers on the project expected to achieve at least 1 Megabit/s download speed from that distance, so the demo’s goals were fully achieved. During the April test campaign, JPL technicians experimented with different use scenarios, from uploading data from Earth to the probe and then re-downloading it the same night, to simultaneously transmitting data to Earth using radio and optical signals at the same time.

During the experiments, the technicians verified problems in the optical band due to thunderstorms or disturbances in the atmosphere. “We learned a lot about how to push the system hard when we have clear skies” writes Ryan Rogalin, DOSC receiver electronics project leader at JPL.”although storms at the Table Mountain and Palomar stations led to interruptions in operations“. JPL is thinking of experimenting with using multiple Earth stations at the same time as if they were one to strengthen the signal and reduce the impact of atmospheric phenomena.

The Psyche probe is on its way to the asteroid of the same name. The primary aim of the mission is to reach and study the asteroid 16 Psyche, one of the most massive bodies in the asteroid belt, to study its morphology and composition and verify whether it is actually the remains of a metallic core of a protoplanet, left bare in following a violent collision. Arrival and insertion into orbit around 16 Psyche is scheduled for August 2029.