The European Space Agency (ESA) has confirmed that its Mars Express orbiter has heard from China's Zhurong rover.
The experiment was to demonstrate that it was possible to relay data from Zhurong back to Earth via the veteran orbiter. In itself not unusual. However, while there is normally some handshaking to be done between spacecraft and trundlebot, two-way exchanges are not possible with Zhurong using the frequencies transmitted by Mars Express. The orbiter therefore had to listen for signals as it sailed serenely overhead.
Experiments began in November and have now concluded. And the result? It worked.
The news was dropped first by China. ESA followed suit shortly afterwards. Test data was sent to from Zhurong to Mars Express (listening "in the blind" so to speak), which relayed that data to the European Space Operations Centre (ESOC) in Darmstadt. The data was then sent on to Zhurong's controllers who confirmed that all had gone to plan.
- ESA tries listening to a red rover on the Red Planet: How did it go? The sound of silence
- China's taikonauts return from heavenly palace after 92-day mission
- China's Mars rover assigned extended mission after exceeding life expectancy
- NASA blames the wrong kind of Martian rock for Perseverance sample failure
"We're looking forward to carrying out more tests in the future," said ESOC systems engineer Gerhard Billig, "to continue to experiment and further improve this method of communicating between space missions."
The test brings some much-needed redundancy to Zhurong's communications. The rover currently relies on the Tianwen-1 orbiter, which transported it to Mars, to relay data to Earth. An additional communication method, even if it is only one-way, is always handy.
It was also a first for the Melacom communication system aboard Mars Express. The "blind" technique had not been used before in orbit around another planet (although thoroughly tested on Earth).
All in all there were five communication sessions planned for November, each lasting approximately 10 minutes. Transmission speeds started at relatively slow 8 kilobytes per second, with a 128 kilobytes per second the target. ®