HELSINKI – China’s first interplanetary mission, Tianwen-1, successfully entered Mars on February 10 after a 202-day journey through deep space.
Tianwen-1 started a nearly 15-minute combustion of its 3000N main engine at 06:52 east, which could slow down the five-ton spacecraft and be caught by Mars gravity.
The Mars import maneuver is designed to place the Tianwen-1 in an elliptical orbit of 400 by 180,000 kilometers, obliquely by 10 degrees, with an orbital period of 10 days.
With more than 192 million kilometers from Earth and a slight delay of 10 minutes and 40 seconds, the brake fire is necessarily pre-programmed. Interference would not be possible in case of a problem.
Tianwen-1 will gradually lower its orbit to make observations of Mars possible. It will also begin preparations for the 240-kilogram solar power plant’s inbound, downhill and landing effort, which is expected to take place around May.
The orbit is expected to approach as close as 265 kilometers to the surface, allowing a high-resolution camera to return images with a resolution of better than 0.50 meters per pixel.
This ability will be used to map a purposeful landing site in Utopia Planitia. Landing coordinates of 110,318 degrees east and 24,748 latitudes north previously appeared in an official Chinese spatial publication before being removed.
Tianwen-1 joins the United Arab Emirates’ Hope mission, which has arrived Tuesday, in orbit around the Red Planet. NASA’s Perseverance Rover will attempt a soft landing on February 18.
Soviet, Japanese and American spacecraft had previously failed at the stage of deployment of the mission. The Soviet Mars 4 mission could not fire its engines and thus continued past Mars, while NASA’s Mars Climate Orbiter came too close in 1999, resulting in a mission-finite interaction with the Martian atmosphere. .
Water ice study under scientific objectives
Tianwen-1 is designed to collect a variety of diverse data, from orbit as well as on the Martian surface.
Long Xiao, a planetary scientist at China University of Geosciences, tells SpaceNews that Tianwen-1 is equipped with a total of 13 scientific payloads to study the morphology and topography of Mars, study the regolith of the surface and search with radars for water ice, the composition of surface material and the properties of the ionosphere, study climate, environment and magnetic field.
“The most unique goal is to look for and map the distribution of water ice on the surface and subsoil,” says Long. Two sounding radars work independently, with one on board the track. It will do a global survey, but more focus on regions with high latitude in the pool. The other one is on the rover. “Because processing and interpretation of radar data is very complex, the ground and satellite radar data together can produce more reliable results than a single one,” says Long.
Zhang Xiaoping, an associate professor at Macau University of Science and Technology, also emphasized the potential of radar payloads.
‘We want to use the radar system to measure the underground structure of the Martian surface, especially for the buried water ice. “This will enable us to study not only the underlying geological structures of Mars, but also the possible source of water ice that provides long-term accommodation for humans,” Zhang said. SpaceNews.
‘It is also important to measure the thickness and layers of ice and carbon dioxide in the polar region, in order to understand the seasonal atmospheric evolution of Mars. By combining orbital and ground penetrating radar results, we will have a better understanding of the ground structure and evolution at the landing site. ‘
Deep space travel
Tianwen-1 launched from Wenchang, South China, 23 July 2020 on a long March 5 heavy lift rocket. The new launcher returned in December 2019 of great importance and was grounded for more than 900 days after a failure in 2017.
The spacecraft performed four ways of correcting the orbit to refine its orbit and a larger deep spatial maneuver to change the orbital angle.
The European Space Agency supported China for the launch and early orbit phase (LEOP) and later during the transfer of Earth and Mars, with very accurate detection via Delta-DOR (Delta Differential One way Range) campaigns. It was carried out with ESA space antennas with a depth of 35 meters in Cebreros, Spain and New Norcia, Western Australia.
The Tianwen-1 orbit has a design life of one Mars year, or 687 Earth Days. The rover, nominated by a public vote and subsequent committee decision, has a design life of approximately 90 Earth days.
The mission utilizes technologies and capabilities developed by the Chang’e lunar program orbits, lander and robbers, as well as head protection and parachuting expertise of Shenzhou human spaceflight
China is also developing a Mars monster return mission for about 2028-30.
