GoKawiilDuring most of the Artemis II mission, the crew of four astronauts beamed back low-definition video, both from inside the spacecraft and from exterior views of the Moon. It was exhilarating stuff, but in a world in which we’re all watching HDTVs, it also felt a little flat.
This is because Orion largely communicated with Earth via radio waves, picked up by large dishes sprinkled around the world. This is pretty much the same way the Apollo spacecraft talked to Earth more than half a century ago.
However, unlike Apollo, the astronauts on Orion would periodically send batches of much higher-resolution data, including the stunning photographs of the far side of the Moon and the Solar eclipse observed from there. This was made possible by optical laser communications, and not just those built by NASA. The mission included a commercial component that could pave the way for vastly more data returning to Earth from space than ever before.
Laser comms works
Apollo returned data to Earth at about 50KB per second using radio frequencies. Similarly, Orion used S-band for a slightly higher communication rate most of the time, at 3MB to 5MB per second. But when the spacecraft turned on its optical communications terminal and connected to ground stations, the data rate increased to 260 Mbps. At those speeds, the crew could have transmitted a full high-definition movie to Earth in seconds.
But that did not happen for a couple of reasons. The first is that the optical communications system was experimental, and the second is that NASA had only three ground stations capable of receiving and processing these laser signals back on Earth: two in the United States and one in Australia.