ESA tries listening to a red rover on the Red Planet: How did it go? The sound of silence

The European Space Agency (ESA) has made its first attempt to pick up data transmitted by the China National Space Administration's (CNSA) Zhurong rover for relay back to Earth.

Using orbiters as relays is a relatively common practice and means landers require less payload for transmitters and more for instruments. A short-range radio can transmit science data to an orbiting spacecraft, which can then be relayed back to Earth.

In the case of Zhurong rover, which landed on Mars in May 2021, data is being relayed back using the Tianwen-1 orbiter. However, using the orbiters of other agencies represents a useful backup and last weekend was the first link-up.

ESA's veteran Mars Express orbiter, which is approaching its 20th year in orbit around Mars (the spacecraft arrived on Christmas Day 2003), is equipped with a Melacom communication system, designed to listen out for any signals from the planet.

The payload was originally flown in support of the ill-fated Beagle-2 lander, but has subsequently been used to communicate with other hardware on the surface.

just checking the updated lander IDs for the switch on sequence for the Mars Express UHF radio.
We have an entry for each lander the radio is configured to talk to and we've added a new one at the bottom for some upcoming tests.

i wonder who ZRR could be? 🤔🤔
🛰️🔴🚗 pic.twitter.com/7PN9tZSVfh

— Simon Wood (@marwood82) October 27, 2021

Sadly, however, there are some compatibility issues with CNSA's take on a trundlebot. While a handshake would normally take place in order to kickstart communications, such two-way action is not possible as Zhurong cannot receive the frequencies transmitted by Mars Express.

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However, the Melacom radio system on the orbiter can listen for a signal being transmitted "blind" from the rover. Any data in the broadcast can then be recorded and transmitted back to Earth (in this case, ESA's ESOC operations centre in Darmstadt).

Testing was already accomplished on Earth, using flight spares, and five tests are scheduled at Mars during November, to fit in with CNSA's mission planning and also when ESA's Mars Express is able to "see" the Zhurong landing site.

The first test occurred on 7 November. ESA has yet to confirm if its veteran orbiter actually heard from the Chinese rover, only telling The Register that "a technical review meeting" was set for Wednesday.

Other than that the agency has been silent. In the way that we hope Zhurong was not. ®