At any moment, dozens of experiments are underway on the International Space Station, from testing how ants problem-solve in microgravity to developing robots that can assist astronauts. All of those experiments, on top of the space station crew’s daily communications with Earth, add up to a lot of data.
The ISS’s current reliance on radio communication means that its crew has to pick what data is worth sending back to Earth. But NASA’s Optical Payload for Lasercomm Science team wants to make it possible to send 10 to 100 times more information at a time by converting data into a laser beam that will travel from the ISS to Earth. If the team is successful, their work could open up the possibility of more data-intensive experiments and even streaming video from distant locations like Mars.
OPALS’ 600 pound instrument was scheduled to take off on SpaceX’s Falcon 9 rocket today, but the launch has been delayed until at least April 18. Once OPALS arrives at the ISS, it will be affixed to the outside of the space station on a 4 x 4.5 foot plate.
“We–JPL, NASA, humans–are making science instruments that gather just an awfully large amount of data. Just a huge amount. And we can’t possibly get it all back with radio communications right now,” OPALS project manager Michael Kokorowski said in an interview at NASA’s Jet Propulsion Lab. “Really, what optical communication will do is make that pipe larger. It has the potential to make every mission just that much more useful because of the return.”
Sending data in the form of lasers is not new. The internet is supported in part by fiber optic cables that transfer information as pulses of light. And NASA has recently experimented with laser communication from as far away as the moon on its LADEE spacecraft.
What OPALS adds to the equation is accurately beaming the laser from a moving vehicle. OPALS will spend 2 minutes during each 92-minute-long orbit around the Earth directing a laser at a target that measures just three feet across. Considering that the ISS moves 17,500 miles per hour relative to the ground and is more than 200 miles above the Earth’s surface, achieving that level of precision is no easy task.
“It’s like taking a laser pointer and holding it on the size of a human hair from about 20 feet away while you’re walking along,” Kokorowski said, attributing the analogy to another OPALS team member. “That’s the kind of pointing that we need for this to work.”
OPALS will direct the laser by spotting a beacon signal that will emanate from the target on Earth. It will need to constantly readjust the direction of the laser, as the ISS moves 5 miles a second. OPALS would eventually like to test sending a laser from Earth to the ISS, but at this time there is no receiver on the space station.
The project is still an experiment. Kokorowski said that OPALS has tested sending the laser across a room, but can’t know for sure what to expect on the ISS. There will be the difficult job of directing the beam, but OPALS will also face other obstacles like vibration and noise from the ISS and its affiliated experiments.
The project could be of interest to commercial entities like Google and Facebook, which are working on transmitting data from satellites and high-altitude drones. Kokorowski said OPALS has received some commercial interest, but would not say anything further.
“We are not the only ones thinking about it,” Kokorowski said. “But we are certainly the ones thinking about it for science and for space, and for Mars and outer planets.”