Europe’s Mars orbiter relays data from Chinese rover back to Earth
The European Space Agency’s Mars Express collected data from China’s Zhurong Mars rover and successfully sent it to Earth following a series of experimental communications tests.
The Zhurong rover was designed only to communicate with its companion orbiter, Tianwen 1; however, the rover has long outlived its planned mission and the orbiter is no longer able to do as much data relaying. So China and Europe decided to try an experiment: Send data from Zhurong to Mars Express to Earth. That’s challenging, since the robots’ communications equipment doesn’t match. Zhurong can transmit at a frequency Mars Express can detect, but not vice versa, so Zhurong sends data without hearing back from the orbiter.
On Nov. 20, Mars Express passed 2,500 miles (4,000 kilometers) above Zhurong’s location in Utopia Planitia, received a batch of data, then transmitted the data across 230 million miles (370 million km) of space to European Space Operations Center ground stations, which then forwarded the data to the Beijing Aerospace Flight Control Center.
Related: China’s Mars rover Zhurong just snapped an epic self-portrait on the Red Planet (photos)
“Mars Express successfully received the signals sent by the rover, and our colleagues in the Zhurong team confirmed that all the data arrived on Earth in very good quality,” Gerhard Billig, a systems engineer at the European Space Agency (ESA), said in a statement.
Mars rovers collect a wealth of science data down on the surface but don’t carry large communications arrays. Insead, they rely on orbiters to relay their high volumes of data across the inner solar system to Earth.
Normally a rover and orbiter will exchange short messages to establish two-communications and transmit data. But, according to ESA, Mars Express transmits its “hello” signal using communication frequencies that are different from those the Chinese Zhurong Mars rover receives, making two-way communication impossible. However, Zhurong can transmit signals using a frequency that Mars Express can receive, so ESA carried out a first test of a one-way communication technique: communication “in the blind,” where the sender can’t be sure if their signal is being received.
Zhurong, China’s first Mars rover, landed on the Red Planet in May this year and has been exploring Utopia Planitia. With only a small antenna on the rover, its companion Tianwen 1 orbiter has been relaying Zhurong’s science data to Earth. But with the start of Tianwen 1’s own science mission in November, the opportunities for relaying the valuable information from Zhurong have been reduced. Instead, the orbiter is focused on mapping Mars.
Existing cooperation between ESA and the China National Space Administration (CNSA) opened the way for a series of five communications tests between Mars Express and Zhurong, all carried out in November. (ESA also provided ground station support for various moments during Tianwen 1 and Zhurong’s journey to Mars.)
Mars Express received a signal during each of the five tests, but during four of these, the received data was corrupted, an ESA spokesperson…
Read More: Europe’s Mars orbiter relays data from Chinese rover back to Earth