The O2O laser-infrared connection system will be tested on board the Orion: a mass of data, better quality, 4K video. The farewell to traditional radio communications begins
There is one more reason to follow the launch of Artemis online on the night of April 2 (Liftoff at 00:24 Italian). If a few decades ago we were used to seeing the first images from space a little blurry, and over the years we got used to the perfect connections from the International Space Station, now, during its 10-day journey around the Moon, the Artemis II mission will rely on NASA’s Near Space Network (NSN) and Deep Space Network (DSN) for main communications with Earth. At the same time, the Orion spacecraft will use the «O2O» optical communications system to transmit data from the mission, demonstrating the operational utility of laser communications in a crewed lunar test flight.
You understood correctly, just as Isaac Asimov wrote 80 years ago, and as science fiction films have often imagined, we have managed to modulate light (lasers) to be able to send an enormous amount of data per second, which translates into the possibility of having 4K images from space, but also always intelligible sounds and voices. But above all transmit and receive multiple mission parameters that help prevent failuresto perfectly manage the flight and keep every part of the complicated propulsion system of the largest rocket ever built, the SpaceX SLS, under control.
More data means greater security, the web instead of radio networks
The laser communications they use invisible infrared light to send and receive more data in a single transmission than traditional radio communication systems. Electromagnetic waves in the infrared spectrum can transfer more data in a single link, making them more efficient for data transfer. This is due to both the higher frequency and the width of the signals, which can convey more information than could be sent with traditional radio signals. More data means more discoveries and more confidence; furthermore, these communication systems have small dimensions and weight.
If everything goes as planned, the use of the O2O system will begin in an increasingly operational way in the Artemis III and subsequent missions, progressively replacing traditional radio communications. And to think that, 57 years ago, when the radio installed in Neil Armstrong’s space backpack sent an analogue signal at 2.1-2.3 GHz to the Lem, this was repeated towards the Service module in lunar orbit, and the latter towards the stations on Earth. Today, even cell phones no longer use such a system, but that phase was very important in coming to think about current cell phone networks.
How Orion laser communications work
The O2O terminal installed on the spacecraft is composed of three components: the optical module, the modem and the controller. The optical module is a small one adjustable towards the terrestrial terminals. The modem converts mission data and commands into laser beams and back for communication, and the controller contains a computer linked to Orion’s flight electronic systems to control the telescope’s pointing, keeping the spacecraft in the correct position.
On Earth, i ground station telescopes from NASA’s White Sands Complex, Las Cruces, New Mexico, and the Table Mountain Facility in California, will capture O2O signals. These stations were chosen for their elevated position and the arid environment surrounding them, in order to ensure a stable connection. The clear climate and low cloud cover in both locations help maintain the quality of the laser links, as one of the limitations of laser communications is attenuation by clouds and precipitation.
Finally, the Australian National University will also follow Orion’s O2O transmissions, via the Mount Stromlo observatory (Canberra), from which it will be possible to send communications when, due to the Earth’s rotation, the Artemis II mission is in the shadow of the United States. But then no more signal repeater ships, no more connecting chains: the first O2O receiver that captures communications will be able to route them via the internet to the rest of the world. All this has only one thing in common with old communications: those 1.3 seconds that the speed of light takes to complete the journey between the Moon and Earth.
