Tianwen-1: China launches first independent Mars mission

On safe landing, Tianwen-1 is scheduled to explore the red planet for 90 Mars days.

Credit : Guo Wenbin/Our Space

The first Chinese independent mission to Mars lifted off at 12.41 pm on Thursday. This marks a major milestone in China’s space programme development. According to an SCMP report, a Long March-5 rocket carried Tianwen-1, the probe, from Hainan Island. The probe is likely to enter Mars’ gravitational field in February 2021.

The 5-tonne probe entered a predetermined orbit and kicked off the Mars exploration mission after the Long March-5 rocket travelled over 36 minutes, SCMP quoted Xinhua as saying. This is the second Chinese mission to Mars. China, along with Russia, had sent the Yinghuo-1 spacecraft to orbit around Mars nine years ago. However, Yinghuo-1 stopped functioning in orbit due to a glitch. The China National Space Administration later said they lost it.

On safe landing, Tianwen-1 is scheduled to explore the red planet for 90 Mars days. Bao Weimin from the Chinese Academy of Sciences in June said the landing is the toughest task during the mission, which involves a four-step process taking around eight minutes. The probe comprises an orbiter, a lander and a rover. The lander and rover will make a soft landing on the Martian surface. Later, the rover would examine the red planet’s surface, magnetic field, atmosphere and ionosphere.

The Mandarin word ‘Tianwen’ means “Questions to Heaven”. An ancient poem, written by Qu Yuan in which Qu, born in 340 BC, had asked 172 questions about Chinese mythology, history and religious beliefs. The poem has inspired the probe. Though the launch succeeded, there would be uncertainties during the mission, said a spokesperson.

“If the probe can’t be captured by Mars’ (gravitational field) on the first trial, the orbit of the mission will have to be adjusted,” said Liu Tongjie, the spokesman. “It is critical and of great difficulty – it has to be done in one go.”

“The entry, descent and landing process for a soft landing on Mars is full of uncertainties. The probe will have to identify the terrain and obstacles, and land on its own,” said Tongjie, adding "The rover may have to switch its mode in the eventuality of a dust storm to protect the solar panels from dust, which could halt its recharging." 

The Hong Kong Polytechnic University has developed the spacecraft’s 390 g Mars landing surveillance camera. Chair professor Yung Kai-leung of precision engineering leading the team that produced the camera said the device has the ability to take ultra-wide angle images with few distortions. It is built to withstand extreme temperature differences of 150 degrees Celsius that the probe would encounter during its journey to Mars. The camera is built to survive an average temperature of -62.8 degrees Celsius on Mars. The university claimed gravity 6,200 times more than the Earth’s would not adversely affect the probe.

The mission would investigate morphology, mineralogy, geology, soil and water-ice distribution and space environment on Mars said scientists involved in the mission. “Tianwen-1 is going to orbit, land and release a rover all on the very first try, and coordinate observations with an orbiter,” stated the mission scientists in Nature Astronomy on July 13. “No planetary missions have ever been implemented in this way. If successful, it would signify a major technical breakthrough.”

Missions to Mars have been launched for decades. The Soviet Union first attempted a Mars mission by launching a spacecraft in October 1960, which was destroyed on launch. The Mars 2 orbiter became the first man-made object to reach Mars in May 1971. Later, the landing system stopped functioning and the lander got lost. Soon, the USSR projected a lander to Mars within a week after the failed mission. It successfully landed on the red planet. It could survive only for 14.5 seconds.

The USA successfully performed a first fly-by of Mars in November 1964. It first had sustained the Viking missions in the 1970s. Nasa’s Mars Odyssey, which was sent in 2001, has the record for the longest time spent orbiting a planet other than Earth.

The United Arab Emirates also sent its Mars probe on July 19.