December 11, 2014
The International Space Station has a new blazing fast broadband connection to Earth. During recent testing of the Optical Payload for Lasercomm Science (OPALS) instrument, which is attached to the exterior of the space station, NASA scientists and engineers have shown that laser communications might drastically change the way we communicate with space-based assets.
The International Space station received OPALS in April via a SpaceX Dragon cargo vehicle and it has successfully completed the first four months of its mission. In order to reduce the impact of atmospheric turbulence resulting in data loss, OPALS uses 4 individual lasers that transmit the data which are then received by the Optical Communications Telescope Laboratory’s ground station at Jet Propulsion Laboratory’s Table Mountain Observatory located in Wrightwood, California. The next phase of system development will be the use of adaptive optics, which could dynamically compensate for the turbulence.
“OPALS has shown that space-to-ground laser communications transmissions are practical and repeatable,” said Matthew Abrahamson, OPALS mission manager at NASA’s Jet Propulsion Laboratory in Pasadena, California. “As a bonus, OPALS has collected an enormous amount of data to advance the science of sending lasers through the atmosphere. We look forward to continuing our testing of this technology, which sends information to and from space faster than with radio signals.”
“Four lasers from the ground station travel through the sky toward the space station. Under clear, dark background conditions, it’s very easy for the payload to acquire the ground beacon. Daylight conditions have proven more challenging, but we are working on increasing capabilities during the day as well, through software enhancements,” said Abrahamson.
This new way of communication is a vast improvement over the space station’s previous radio transmission method, and data can be transmitted in seconds rather than several minutes.
A press release from Jet Propulsion Laboratory contained some details of the transmissions:
- In June, Lewis Carroll’s “Alice’s Adventures in Wonderland” was transmitted multiple times.
- A night pass over Table Mountain on June 5 that lasted 148 seconds. A video, with the message “Hello, World!” was beamed from the space station every 3.5 seconds. Normally the 175-megabit video would take 10 minutes to transmit over traditional radio communication systems.
- Between 200-300 MB of engineering data was downlinked, taking only 20 seconds. Normally, it would take 3 hours. The data was completely reconstructed after being received, which highlighted OPALS’ low bit error rate.
- To commemorate the 1969 Apollo moon landing, in July, OPALS beamed a high-definition video of the landing in just under 7 seconds. Using existing radio-based infrastructure, it took 12 hours to uplink the same video to the ISS.
“We’re finding that differing weather patterns and geometry variations are proving to be challenging,” added Abrahamson. “We’ve had a half dozen or so pass attempts with varying levels of success, and we are looking to continuing these collaborations in the future.”
It is almost inevitable that there will be other uses for this technology that would benefit our lives here on Earth. For instance, it is possible that laser communications with satellites could significantly boost the bandwidth into low-Earth orbit as well as geostationary altitudes. This would mean a significant increase for commercial high-definition video and satellite internet access. The scientific possibilities are tantalizing, too. In the future, this technology could be added to rovers exploring other planets, solar systems and other destinations.
“OPALS is going to change the way we communicate with and build spacecraft in the future,” said Abrahamson.