China’s Tianwen-1 orbiter starts remote-sensing exploration of Mars
The orbiter of China’s Tianwen-1 Mars mission completed its fifth braking near Mars and entered its remote-sensing orbit around the red planet on Nov. 8, starting to carry out global remote-sensing exploration of Mars.
China’s Mars rover Zhurong, part of the Tianwen-1 mission, had accomplished its planned exploration and detection tasks and is now conducting additional tasks in good condition.
The research and development team of the mission optimized the design of the orbit according to the needs of the orbiter in conducting Mars detection and relaying communications between the Mars rover and Earth.
With the periareion, the point in the orbit that is closest to Mars, and the apoareion, the highest point of the orbit around Mars, adjusted to about 265 km and 10,700 km respectively, and the orbital period to around 7.08 hours, the improved design enables the Mars orbiter to carry out scientific exploration around Mars while better relay the communication for the rover, thus increasing the efficiency in the implementation of relevant tasks.
The Mars orbiter separated from the lander and rover of the Tianwen-1 mission on May 15. On the same day, the lander touched down on the red planet. After that, the orbiter entered orbit to relay communication between the rover and the Earth.
After relaying communication for the rover for more than four months, the orbiter shifted its orbit recently at the periareion and successfully entered its remote-sensing orbit around Mars.
According to experts, the relay orbit is a recursive orbit along which the orbiter orbited Mars three times a Martian day and passed over the landing site of the Tianwen-1 probe each Martian day, thus relaying communications between the rover and the Earth twice within a Martian day at the periareion and the apoareion, respectively.
With a shorter orbital period than that of the relay orbit, the remote-sensing orbit allows the orbiter to orbit the red planet 3.47 times a Martian day and pass different substellar points to carry out detection tasks in different regions, experts pointed out.
During the remote-sensing exploration of Mars, the scientific payloads aboard the Tianwen-1 orbiter can conduct relatively high-resolution observation of the planet at low orbital altitudes. By leveraging the drift of the periareion caused by orbital perturbations, the orbiter can carry out detection tasks covering the whole planet in the remote-sensing orbit.
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