NASA is developing a first-if-its-kind modem that incorporates light-based technology to help enable dramatically faster communications between spacecraft and ground stations.
The device, which is scheduled to be tested on board the International Space Station in 2020, is part of a broader NASA project called the Laser Communications Relay Demonstration (LCRD). This laser system, which the space agency says could dramatically overhaul today's radio frequency (RF) communications, will enable data transmissions at rates 10 to 100 times faster than what's currently possible.
It's not the first time NASA has experimented with laser communications in place of radio signals. In 2013, the agency achieved record-breaking download and upload speeds to and from lunar orbit – at 622 megabits per second (Mbps) and 20 Mbps respectively – with its Lunar Atmosphere and Dust Environment Explorer (LADEE).
The LCRD project, however, is designed to be the basis of an ongoing operational system once initial tests, due to begin in 2019, are complete. And part of what will help NASA demonstrate the feasibility of its laser communications setup is the new integrated-photonics modem.
Dubbed ILLUMA – for Integrated LCRD LEO (Low-Earth Orbit) User Modem and Amplifier – the tiny device will be about the size of a mobile phone, thanks to NASA squeezing a number of functions onto a single microchip. This means it'll be several times smaller than the fibre-optic receivers in use in spacecraft today.
"Integrated photonics are like an integrated circuit, except they use light rather than electrons to perform a wide variety of optical functions," said Don Cornwell, director of NASA's Advanced Communication and Navigation Division. "This technology will enable all types of NASA missions, not just optical communications on LCRD."
Photonic circuitry isn't new, but refining the technology without creating speed bottlenecks in other components has proven an ongoing challenge for scientists. But if NASA can get them to work as hoped, the benefits could be huge, offering smaller instruments with much improved performance. And like electronic circuits, they can also be mass-printed lithographically, meaning they should be inexpensive to produce.
"We've pushed this for a long time," said lead ILLUMA developer Mike Krainak from NASA's Goddard Space Flight Centre. "The technology will simplify optical system design. It will reduce the size and power consumption of optical devices, and improve reliability, all while enabling new functions from a lower-cost system."
The new functionality won't just be to NASA's advantage in enabling faster data transmissions between satellites and ground stations. If it comes off, this emerging photonic technology could be used in everything from medical imaging and manufacturing to the data centres used by Internet companies.
"It is clear that our strategy to leverage integrated photonic circuitry will lead to a revolution in Earth and planetary-space communications as well as in science instruments," said Krainak. "What we want to do is provide a faster exchange of data to the scientific community… Google, Facebook, they're all starting to look at this technology. As integrated photonics progresses to be more cost-effective than fibre optics, it will be used. Everything is headed this way."