Chinese on Mars. Tianwen-1, a new probe destined for the Red Planet, has been launched.

By: Oasis Team

China's long march to Mars began at 1:40 AM Brasília time on July 23, 2020, with the launch from the Wenchang spaceport on the Chinese island of Hainan: the Tianwen-1 mission, a name that in Chinese means "questions to heaven," will enter Martian orbit in February 2021, with the goal of conducting a comprehensive scientific investigation of the Red Planet. For China, this is the second attempt to reach Mars: the first, in 2011, ended badly with an early plunge into the Pacific after the Russian rocket carrying the Chinese orbiter Yinghuo-1 ran aground due to a technical problem that occurred when the probe entered Earth orbit.

The Tianwen-1 triple probe on the launch pad.

Three in one. China to accomplish a feat.

Mars, during the short period of a few weeks, is moving at a relatively shorter distance from Earth. Tianwen-1 is one of three Martian missions launching during this favorable launch window: the others are Hope, the United Arab Emirates mission that began on July 20th, and Mars 2020, NASA's mission that theoretically launches on July 30th, but no later than mid-August, carrying the probe that will continue the tasks that previous probes like Curiosity and Perseverance have already performed on the surface of the Red Planet. The US space agency can now afford, thanks to the robotic experience gained on Mars, some creative ventures such as the Ingenuity helicopter-drone – which will attempt to fly through the thin Martian atmosphere. China, in turn, wants to recover lost ground in recent years, sending three vehicles to Mars at once, a technical milestone that no other interplanetary mission has ever achieved.

The payload, totaling over 5 tons, includes an orbiter that will follow a polar elliptical orbit around the Red Planet and conduct scientific observations for one Martian year (i.e., 687 days); and a pair of lander-rovers for investigating areas of the Martian surface. This equipment is expected to remain in Martian orbit for several months before descending to the surface. This calculated delay, already used for the landings of the American Viking spacecraft in the 70s, will allow scientists to carefully study the conditions of the Martian atmosphere before attempting a descent, which remains the most dangerous part of the journey to the neighboring planet. The most complicated aspect of the descent to the surface is trying to slow down a spacecraft that has reached supersonic speeds, in order to land on the surface without crashing. Major nations with a long tradition of space exploration have already failed in this attempt. The last was Europe with the ExoMars mission in 2016.

The Tianwen-1 probe recently landed on the surface of Mars (Illustration)

Full analysis

The landing site will be Utopia Planitia (Utopia Plain), a flat area within an impact basin north of the Martian equator. From here, the Chinese six-wheeled, solar-powered rover, very similar to NASA's Spirit and Opportunity predecessors, will embark on a surface exploration lasting approximately 90 Martian days, operating six scientific instruments (including a subsurface-scanning radar) to study Martian geology and check for the presence of ice. Seven other scientific instruments will be aboard the orbiter, which will conduct coordinated observations with the rover, focusing on analyzing the Martian ionosphere, climate characteristics, measuring electromagnetic and gravitational fields, as well as the internal structure of Mars.

The potential landing site is Utopia Planitia, a colossal crater in the northern hemisphere, formed by a meteorite impact millions of years ago. It offers two potentially interesting aspects for a country attempting to land on Mars for the first time: the plain is low-lying, therefore it has more atmosphere, which slows the module down through friction—a crucial factor because the Martian atmosphere is much thinner than Earth's. Furthermore, this plain is believed to have less rugged terrain than other locations. But there is a third, undisclosed reason that makes this area interesting: it is full of water.

The Chinese rover on the surface of Mars (Illustration)

The strategy of patience

The Chinese space program is closely linked to the country's military operations, and this, along with the traditional secrecy surrounding Chinese space missions, has contributed to maintaining partial secrecy regarding the details of the Tianwen-1 mission. Furthermore, statistics show that half of the attempts to land probes on Mars so far have failed. But if, despite any possible inconvenience, Tianwen-1 reaches Mars next February, the images taken by its orbiter could reach us at the same time as those from the American Perseverance rover. That alone will be enough for the Chinese mission to be considered a success.