Laser Communication with Spacecraft

New technology promises to take laser communication with spacecraft from science fiction to science fact. This technology offers a new answer to a 60-year-old problem: you have had your launch and your shiny new space probe has made it to orbit without being ripped to shreds by tons of exploding chemical fuel, but once it’s up there, how do you talk to it?

The conventional answer is radio waves, but the rate of information transfer is woefully slow – just ask any NASA scientist who has tried to distill usable data out of probe transmissions. There are no ‘subspace’ communications in the real world, just lots of waiting while the precious data rolls in at the same old pace.

But, thanks to new laser technology, this is about to change.

Radio waves have been the standard since the dawn of spaceflight, but the new optical communications has the potential to increase that rate by as much as 10 to 100 times. That means instead of painstakingly assembling still photographs, we could actually get high-res photos or even video from the surface of other planets, or moons like Titan. How cool is that!

This new communication system will also be crucial as spacecraft are sent further into the solar system, stretching conventional radio transmissions to the limit.

The key factor is that while both radio and lasers travel at the speed of light, lasers use a higher-frequency bandwidth, allowing the transmission of much more data. The typical rate of information transfer might around a few megabits per second (Mbps). For example, NASA’s Mars Reconnaissance Orbiter sends data at a maximum rate of around of 6 Mbps. Using laser technology of equivalent size and power rating would probably increase this to 250 Mbps – a huge improvement.

There are some possible wrinkles though. Clouds and atmospheric conditions can cause interference in laser transmissions. And receiving those transmission will require a whole new Earth-based infrastructure – preferably in areas with clear skies.

Radio’s reliability will ensure it will endure as a communication method, but the new technology will continue to step closer to widespread application. The Laser Communications Relay Demonstration (LCRD), led by NASA’s Goddard Space Flight Center, will launch in 2019. This probe will test signals between two new ground-based stations and geostationary orbit, a distance of 40,000 km. This will be followed by the Deep Space Optical Communications (DSOC) probe, led by JPL, in 2023, which, along with other science goals, will test transmissions between Earth and its target, a nearby metallic asteroid.

In my novel, The Tau Ceti Diversion, the explorers use laser communications to stay in contact with Earth – well at least until an unnamed saboteur puts the beam out of alignment:) Read more about the story and check out the free sample chapters on Amazon!

Tau-Ceti-Diversion-severed-ebook-cover (Medium)

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