Satellite operators usually send commands as digital packets over radio, but one group of amateur radio operators tried something a little more conversational: They spoke the command into a microphone. Specifically, they verbally instructed an Earth-orbiting satellite to launch Doom, marking what appears to be the first time a spoken instruction has been successfully sent to and executed by a satellite.
The Oslo-based group sent a voice command to the European Space Agency’s OPS-SAT PRETTY, an experimental cubesat launched in 2023. The message was simple: “PRETTY PLAY DOOM.” Sure enough, the satellite detected the command and launched the 1993 first-person shooter video game. It even downlinked a postcard image of the moment, according to Tanagra Space, which develops machine learning that runs on board spacecraft.
While the experiment was a fun demonstration, it could also point toward more practical applications for satellite communications. The ability to recognize and respond to spoken commands could eventually help pave the way for more responsive satellites capable of listening for distress calls or emergency signals and reacting accordingly.
Just say the word #
Satellites normally receive commands from Earth through radio-frequency signals transmitted by ground stations. The process is called telecommanding, and it works a little differently from simply talking to a device.
Satellite operators use specialized software to create digital commands, such as an instruction to adjust the spacecraft’s orientation. A ground station then uses a high-gain antenna to beam those commands to the satellite as encoded radio signals. An onboard radio receiver picks up the signal, and the spacecraft’s computer decodes the digital instructions before carrying out the request.
According to Tanagra Space, the July 27 experiment marked the first time a satellite recognized and carried out a spoken command on its own. The amateur radio operators tested the system twice that day. During the morning session, they transmitted a synthesized voice message on a continuous loop. Later that evening, they took things a step further, with an operator speaking directly into a microphone to issue the command.
Both times, OPS-SAT PRETTY was able to capture the radio signal, recover the voice from the noise, and transcribe it with a speech-to-text AI model. The satellite then detected the command and acted on it autonomously.
A satellite that listens #
ESA’s OPS-SAT PRETTY satellite is equipped with a processing pipeline designed to recognize voice commands, allowing it to process the incoming audio and recognize the spoken words.
The team behind the experiment believes voice-commanding satellites could have different uses in the future. “Maybe there is an application there in terms of capturing [distress calls] on a global scale and acting on them immediately, instead of waiting until a Coast Guard or another ship,” Georges Labrèche, the principal investigator on the project and founder of Tanagra Space, told SpaceNews. “Maybe this could be turned into a service where suddenly you can point to the air, call out for mayday and then a network of satellites is able to relay that immediately.”
The feature could also be used for space-based observations. “When you do astronomical observations, like observing gamma-ray bursts or black holes colliding, you’re looking for signals with very specific patterns,” Labrèche said. “So maybe there is a near future where instead of training a model to recognize a human voice, we train a model to recognize these astronomical events directly on board the satellite, so we can detect them more immediately.”