NASA Sets Mind-Boggling 200Gbps Space-To-Ground Speed Record Using Lasers

Researchers have set a new record for the fastest space-to-ground laser communications with data rates of 200 gigabits per second. The blistering speed is 100 times faster than the swiftest internet speeds in most major cities, and is capable of transmitting more than 2 TBs of data in a single five-minute pass over a ground station.

The TeraByte InfraRed Delivery (TBIRD) system is around 530 kilometers above Earth in low-Earth orbit (LEO). It is part of NASA's Pathfinder Technology Demonstrator 3 (PTD-3) satellite, which launched in the Spring of last year. A group of researchers from NASA, MIT, and other institutions have achieved data transfer speeds utilizing TBIRD 1,000 times faster than the current radio links traditionally used for communications with satellites in space.

The importance of being able to send data at such high speeds is essential for future missions. Kat Reising, an aerospace engineer and staff member at MIT's Lincoln Laboratory on the TBIRD team explains, "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." She added, "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."

Currently, space-based communications between space agencies and commercial satellite operators typically use radio to communicate with spacecraft in outer space. By employing an infrared light that laser communications can utilize at a far higher frequency than radio waves, the team says much higher data rates are possible.

TBIRD has not been without its challenges, however. The first obstacle the team had to overcome was how to cool the fibers in the optical signal amplifier, which melted during an initial test. To solve this issue, the team worked alongside the amplifier's vendor in order to modify the unit so it released heat through conduction.

Another issue that arose was experiencing distortion from atmospheric effects and weather conditions, which caused a power loss. To overcome this issue, scientists invented their own automatic repeat request (ARQ), which is a protocol for controlling errors in data transmission over a communications link. This essentially allowed the ground crew to determine which frames it collected correctly, and then tell the satellite which ones needed to be retransmitted without having to resend data it had already successfully sent.

Riesing noted that TBIRD's architecture supports multiple channels through wavelength separation to enable higher data rates, which is what made a 200 gigabit-per-second downlink possible late last month. She explained, "This can scale further on a future mission if the link is designed to support it."

NASA's Pathfinder Technology Demonstrator (PTD) missions which TBIRD is a part of are testing the operation of a variety of novel CubeSat technologies in low-Earth orbit, providing superior enhancements to the performance of these small and effective spacecraft. It aims to demonstrate a new subsystem of technologies that will boost small spacecraft capabilities, enabling direct infusion into a wider range of future science and exploration missions, according to NASA.