This summer, new space missions will seek to revolutionise space communications by rapidly transmitting vast volumes of data, including high-definition video from the moon, using laser beams.
The US government will conduct two flights to test such lasers, which employ invisible infrared light beams.
NASA’s Laser Communications Relay Demonstration will look at the best ways to use lasers to transmit information back to Earth from space. A secondary experiment, known as LINCS, will focus on beaming laser communications between two tiny satellites for the Department of Defense.
Also, NASA’s Orion spacecraft being prepared for launch later this year on an uncrewed lunar mission will use lasers on future missions to send high-definition video of the moon back to Earth.
The main goal for NASA’s laser demonstration spacecraft is to determine how Earth’s atmosphere, especially clouds, influences laser links to the surface, David Israel, NASA architect for exploration and space communications, said in an interview.
The lasers will allow “a whole day’s worth of video or observation data to just be blasted down in one quick pass,” Israel said.
Israel worked on a new $310 million mission. Scheduled for launch this summer, the spacecraft consists of receivers and a laser transmitter and is no bigger than a king-sized mattress, according to NASA.
Launch provider ULA postponed a June 23 target date to evaluate an issue with the rocket’s engines and hasn’t yet set a new date.
The relay demonstration satellite will orbit the Earth for years, eventually testing the transmission of large amounts of data from the International Space Station to ground stations in Hawaii and New Mexico, Israel said.
If clouds are too thick at the intended ground station, laser transmitters could be adjusted to find other receivers, he said.
“We have models and predictions, but we don’t have much in the way of actual data to really characterize how bad the effects of weather will be,” Israel said. “We will measure the impact of weather so we can better predict good transmission conditions.”
The light beams of infrared lasers travel no faster than radio waves, but lasers can pack 10 to 100 times more data into a relatively quick beam. Such density would allow transmission of maps for the entire surface of Mars in about nine days, compared to nine months for radio waves, NASA said.
Laser communications will aid a new era of spaceflight for private companies, such as SpaceX and Blue Origin, said Debra Emmons, general manager of communications technologies and engineering at the non-profit, California-based Aerospace Corp., a think tank for the U.S. defense department.
“The ability to communicate and operate interchangeably between space assets will be critical … as we set sights to the moon and beyond,” Emmons said in an email.
“The sheer distances require laser-based communication — not for speed, but for smaller size, weight, and power of optical terminal payloads compared to larger radio frequency [equipment].”
Laser communication is more secure than radio transmission due to the tighter, narrow beam of data, Emmons said.
“The chances of intercepting a laser beam are much smaller,” she said. “One has to be in the path of a laser beam to intercept any data, whereas radio waves scatter, and therefore can be intercepted more easily.”
The study of such lasers is expanding rapidly, Peter Delfyett, professor of physics, optics and photonics at the University of Central Florida, said in an interview.
“We’re talking about massive amounts of information to be transmitted quickly, within a few seconds or minutes,” Delfyett said.
He compared laser communications to fiber-optic communications on the ground, but without the usage of fibre.
In most cases, infrared lasers pose no major harm to people and would be invisible unless someone wore infrared goggles, according to Delfyett.
When NASA sends Artemis missions to the moon, the public will be able to see the advancements in communication made possible by lasers, according to NASA’s Israel.
“When that first flyby of the moon happens and high-definition video is streaming back, that’ll be coming through an optical [laser] link,” he explained.