Gathering light, decoding data
At a high level, the concept is fairly straightforward. A spacecraft encodes data onto a laser, which sends a narrow beam toward Earth. Large optical telescopes on the ground collect the incoming photons, and detectors convert the light back into electrical signals. Sophisticated error-correction software reconstructs the original message as many photons are lost.
The greater the distance, the more daunting the challenge. A laser beam from geostationary orbit, about 22,000 miles (36,000 km) above Earth, starts out about the diameter of a coffee cup, and when it reaches Earth, it’s about 1km across. The further away, the further the beam spread, so ground-based telescopes can capture only a tiny fraction of the signal from distant spacecraft.
The future of communication throughout the heavens will therefore probably be based on relay spacecraft, which are essentially like Internet routers here on Earth. “We’re going to be building the systems that get deployed in space, and become the fiber optics infrastructure of communication across the Solar System,” Roelker said.
That’s the vision, at least.
But it is starting to happen. Observable Space played a key role in facilitating optical communications on Artemis II in April as it flew around the Moon. This type of high-bandwidth communications is expected to become standard for future Artemis missions and will enable lunar landings in high definition.
Australia National University provided space-to-ground laser communications for Artemis II with an Observable Space RC700 lasercom-optimized system at Mount Stromlo Observatory, Canberra, ACT, Australia.
Credit:
Nic Vevers/ANU
Observable Space is also talking to SpaceX and everyone else interested in developing orbital data centers because that technology needs high-bandwidth links from space to ground. And the way to get around clouds is to have lots of ground stations around the planet. That’s why Observable Space is focused on scaling up telescope production and lowering costs.
Investors are buying in. In late May, the company announced it had closed a $90 million Series A funding round and would use that money largely to accelerate its laser communications business.
Roelker is happy to leave it to other companies to launch into space. He’s seen SpaceX from the inside and knows he could never compete with that. Likewise, there are many companies building spacecraft and satellite buses.
What those vehicles all need is the command of light. Rockets, and particularly spacecraft, need it to navigate. They need to see objects to avoid collisions. And somehow, with all of the data they are collecting and processing, they need to get it back to Earth. Because, otherwise, what’s the point?
