China arrives around mars

China arrives around mars

One day after the United Arab Emirates with Hope, it was the turn of China to put its probe, Tianwen-1, into orbit around Mars on 10 February. In May-June, it has to release a rover which will land in the Utopia Planitia region.

Over the Martian summer of 2020 which saw the departure of 3 probes to the fourth planet of the Solar System, the Chinese Tianwen-1 was the second on 23 July. On 10 February 2021, logically it was the second of this exploratory robotic “fleet” to reach the destination.


Thus, after a little more than six months of travel, having covered 475 million kilometres, Tianwen-1 automatically carried out the manoeuvre which had been programmed by the ground teams of the Chinese space agency, CNSA. Indeed, the radio delay between Mars and Earth (about 11 minutes currently) rules out any direct piloting.

Image de Mars acquise par Tianwen-1 alors qu’elle s’approchait de son but et publiée début février. Crédit : CNSA

Image of Mars by Tianwen-1 on approach to its target, published in early February.
Credit : CNSA

By switching on its engine on 10 February at 11.52 Universal Time for 15 minutes, Tianwen-1 slowed down enough to be captured by the Martian gravitational field. It follows a very elliptical orbit of 400 to 180,000 km which takes around ten days.


This will not be the Chinese probe’s working orbit. After several manoeuvres, it is aiming for an orbit around Mars at 265 km at its closest and 12,000 km at its furthest point. Moreover, Tianwen-1 is, in a way, a double probe. There is, of course, the orbiter part, with the mission of studying the planet from orbit with seven instruments. But there is also a capsule section. This is the double aspect of it. However, this capsule houses a lander and a rover (with the orbiter, that makes it a triple probe) which will detach itself in May or June to attempt to land.

Alors qu’elle voguait vers Mars, Tianwen-1 a largué un petit satellite qui l’a prise en photo. On remarque les panneaux solaires et l’antenne de communication sur la partie orbiteur. La forme conique blanche est la capsule qui contient l’atterrisseur avec le rover. Crédit : CNSA

While it was sailing to Mars, Tianwen-1 released a small satellite which took its photo. The solar panels and the communications antenna on the orbiter section can be seen. The white conical shape is the capsule which contains the lander with the rover.
Credit : CNSA

For its first independent mission to Mars (the Chinese probe Yinghuo-1 was a passenger of the Russian Phobos-Grunt mission which failed in 2011), China therefore chose not only to study this planet from orbit, but also from the surface. The orbiter section will carry out surveys of the Utopia Planitia region which was selected for the landing. In May or June, the capsule will detach itself and enter the Martian atmosphere, protected by a thermal shield. After a parachute phase, the lander will be released and land using reverse thrusters. Once on the ground, a ramp will be deployed so that a 240 kg rover, powered by solar panels and equipped with six instruments, can disembark. CNSA has announced a 90-day surface mission. The orbiter is planned to operate for two terrestrial years.

Illustration du rover de Tianwen-1 sur sa plateforme d’atterrissage. Crédit : CNSA

Illustration of the Tianwen-1 rover on its landing platform.
Credit : CNSA

The rover’s name has not yet been chosen. After a call for ideas, ten suggestions have been chosen: Hongyi (Persistence), Qilin (a mythological animal), Nezha (a protective divinity), Chitu (Red Hare), Zhurong (a legendary character), Qiusuo (the verb to search), Fenghuolun (Wheel of Wind and Fire), Zhuimeng (Dream Hunter), Tianxing (Heavenly Walker) and Huoxing (the planet Mars). The vote on the web ends.




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