A Mars probe is launched on a Long March-5 rocket from the launch site of the Wenchang spacecraft in southern China’s Hainan province on July 23, 2020. (Xinhua / Cai Yang)
BEIJING, July 26 (Xinhua) – The Chinese spacecraft Mars has embarked on a long journey with great risks and challenges for Earth’s neighbor.
China’s first Mars exploration mission, Tianwen-1 (which means Questions to Heaven) aims to orbit, land, and roam Mars on one mission, an unprecedented achievement.
Mars will be the focus of China’s deep space exploration, and the Mars mission has a higher starting point because China laid a good foundation and accumulated experience in its lunar exploration program, said Geng Yan, an official with the Center for Exploration and Lunar Space of the National Space Administration of China.
China is late for planetary exploration. Chinese space experts believe the objective of the exploration should be accessible, but not too easy.
“We hope the mission is innovative and helps drive scientific and technological development,” said Geng.
However, the challenges are also unprecedented.
Although China has achieved a number of successes in lunar exploration with four probes sent to the moon, Mars poses new difficulties for designers of Chinese spacecraft.
One of the biggest differences between the moon and Mars is that the moon has no atmosphere, while Mars has a thin atmosphere. Landing on the moon does not require an aerodynamic shape or a parachute. Engineers want to use the atmosphere of Mars to help slow down the spacecraft, but they have only a limited understanding of the unstable atmosphere, Geng said.
A Mars probe is launched on a Long March-5 rocket from the launch site of the Wenchang spacecraft in southern China’s Hainan province on July 23, 2020. (Xinhua / Cai Yang)
The difference in gravity also demands differences in the design of Mars and the lunar rovers. The solar panels on the Mars probe are different from those on the lunar probes because of the different light intensity.
Probe designers also worry about sandstorms on Mars, and have tried to minimize the risk of sand and dust damage.
The average distance from Earth to the Moon is approximately 380,000 km, while the distance to Mars is up to 400 million km, which is a great challenge for communication and control, Geng said.
“China’s Tianwen-1 mission includes an orbiter and a rover, so we are actually sending two probes to Mars together,” said Geng.
The designers of the spacecraft had to take into account all aspects of orbit, landing, and displacement in a single mission.
More than 40 missions to Mars have been launched since the 1960s, but only half have been successful. The success rate for landing is even lower, and only the United States has managed to land smoothly on Mars.
“We only have a limited understanding of Mars. There are still a lot of uncertainties about the environment and great risks,” Geng said.
The design of the aerodynamic shape and parachute of the Mars probe are quite different from that of the return capsule of a manned spacecraft on Earth, Geng said.
There are many key steps that require the spacecraft to be highly reliable.
The team had a brief R&D time and challenges to test the spacecraft on Earth. “It is immensely difficult to simulate the environment of Mars, and we conducted many special tests of the entry pod parachute and the scout vehicle,” Geng said.
If China can succeed in orbiting, landing, and touring the red planet at Tianwen-1, it will face the challenge of collecting and bringing samples on the next mission to Mars, as well as exploring asteroids and the Jovian system, Geng added. ■
