IEEE Spectrum by Charles Q. Choi 5/29/2023
NASA's Laser Link Boasts Record-Breaking 200 Gbps SpeedResearchers doubled the downlink record they set just last year
A group of researchers from NASA, MIT, and other institutions have achieved the fastest space-to-ground laser communication link yet, doubling the record they set last year. With data rates of 200 gigabits per second, a satellite could transmit more than 2 terabytes of data—roughly as much as 1,000 high-definition movies—in a single five-minute pass over a ground station.
“The implications are far-reaching because, put simply, more data means more discoveries,” saysJason Mitchell, an aerospace engineer at NASA’s Space Communications and Navigation program.
The new communications link was made possible with the TeraByte InfraRed Delivery (TBIRD) system orbiting about 530 kilometers above Earth’s surface. Launched into space last May, TBIRD achieved downlink rates of up to 100 gigabits per second with a ground-based receiver in California by last June. This was 100 times faster than the quickest Internet speeds in most cities, and more than 1,000 times faster than the radio links traditionally used for communications with satellites.
The fastest data networks on Earth typically rely on laser communications over fiber optics. However, a high-speed laser-based Internet does not exist yet for satellites. Instead, space agencies and commercial satellite operators most commonly use radio to communicate with objects in space. The infrared light that laser communications can employ has a much higher frequency than radio waves, enabling much higher data rates.
“There are satellites currently in orbit limited by the amount of data they are able to downlink, and this trend will only increase as more capable satellites are launched,” says Kat Riesing, an aerospace engineer and a staff member at MIT’s Lincoln Laboratory on the TBIRD team. “Even a hyperspectral imager—HISUI on the International Space Station—has to send data back to Earth via storage drives on cargo ships due to limitations on downlink rates. TBIRD is a big enabler for missions that collect important data on Earth’s climate and resources, as well as astrophysics applications such as black hole imaging.”
MIT’s Lincoln Laboratory conceived TBIRD in 2014 as a low-cost, high-speed way to access data on spacecraft. A key way it reduced expenses was by using commercial, off-the-shelf components originally developed for terrestrial use. These include high-rate optical modems developed for fiber telecommunications and high-speed large volume storage to hold data, Riesing says.
More:
https://spectrum.ieee.org/laser-communications
