Communication between the Earth’s surface and the vast number of satellites we’ve launched into space is crucial. However, some of the communications technology we use now doesn’t have the bandwidth to efficiently handle all the data our current, high-tech satellites are generating. A new collaboration between engineering researchers at the Georgia Institute of Technology and satellite communications provider Xenesis aims to open up this bottleneck that currently limits the flow of data coming from Earth-orbiting satellites to ground stations.
The joint project will miniaturize, space qualify and test a laser communications transceiver that could significantly expand the bandwidth available for downlinking information from satellites. This is also essential because of the expected future constellation of space vehicles to occupy low-Earth orbit, which will increase communication data exponentially.
“We expect to significantly add to the total bandwidth of information that we can get down from space, and the more bandwidth we have, the more information we can exchange and the more value we can get from satellite networks,” said Brian Gunter, an assistant professor in Georgia Tech’s School of Aerospace Engineering and one of the leads on the project.
Xenesis, Georgia Tech and NASA’s Jet Propulsion Laboratory (from where the technology is being licensed) plan to mature it for use as a primary communication system for satellites as small as CubeSats.
Gunter’s lab at Georgia Tech already has experience with small satellites, and plans to apply this expertise to the collaboration with Xenesis. Georgia Tech’s contribution will be to miniaturize the original JPL technology, update the control software, space qualify all the hardware and test the improved system from space. The testing will likely be performed from the International Space Station.
“With all of the satellites that are going into space, everything from CubeSats to major satellites, there is more information being generated than can ever be downloaded,” said Dennis Poulos, chief technology officer at Xenesis. “Most of today’s systems depend on radio frequency downlinks, and there is just a limited amount of bandwidth available for use.”
Using laser-based systems could expand that bandwidth to 10 gigabits per second and beyond, Poulos said. In addition to boosting bandwidth, optical systems can use smaller antennas, use power more efficiently, and provide better data security.
JPL’s laser communications transceiver consists of two components:
- An optics module that includes a five-centimeter telescope, two-axis gimbal, monitoring sensors and thermal control system
- An electronics module with a transmitter, processor, controllers and power conditioning systems
Though the laser-based system is subject to interference from clouds, it will benefit from producing a narrow beam that can travel farther than comparable radio-frequency transmissions at the same power level.
The initial focus of the project will be space-to-ground communication, though the system could also be used for cross-linking communication between satellites. The small antenna size is also suitable to the small-form satellites envisioned for future constellations that may include thousands of spacecraft.
“Once we can show that this works from space to ground, that will demonstrate that the technology can survive the harsh environment of space, and allow us continue the development of the transceiver for commercial use,” Gunter added. “This has the potential to open up a range of new capabilities, including the ability to provide high-volume data services to anywhere in the world.”
Mark LaPenna, CEO of Xenesis, compared the benefits of the planned space-based network to the jump in performance from terrestrial dial-up connections of the 1990s to today’s high-speed broadband services.
"Xenesis recognizes the need for a global communications revolution, and we plan to empower space with an optical product called XenHub,” LaPenna said. “Through this architecture, any company, mission or global operator on the ground or in space, will be able to compete on a level playing field for the first time since Sputnik."
In Georgia Tech’s School of Aerospace Engineering, the contract will support three or four graduate students, a postdoctoral researcher, and a group of undergraduate students, Gunter said. “This will be a major satellite project for our lab, and we look forward to advancing the technology with our collaborators.”
Xenesis has licensed the technology from NASA’s Jet Propulsion Laboratory (JPL).
For other cool space projects, check out 3 Challenges to Engineering a Space Elevator.