WHAT’S THE STORY?

JUST like the proverbial Edinburgh buses, the planet Mars had no Earth vehicles tootling around its surface for four billion years, and then along have come six at once – well, if you can consider 24 years being “at once”.

Over the weekend, the Tianwen-1 spacecraft landed its rover on Mars, China becoming only the second nation to successfully land such a robotic vehicle on the Red Planet. The six-wheeled rover is called Zhurong, the name of a fire god in ancient Chinese mythology.

Only the USA had previously landed rovers – in effect mobile laboratories – on Mars. Zhurong joins Nasa’s Sojourner, Opportunity, Spirit, Curiosity and Perseverance on the roll of honour.

Sojourner was the first wheeled vehicle to rove around on another planet, doing so in 1997. Perseverance only landed in February and is known for its helicopter-like drone device called Ingenuity, while nearly nine years after it made Mars-fall, Curiosity is still operational, a remarkable achievement considering that it was supposed to last just two years.

Zhurong’s mission is planned to last only 90 days, and during its stay there will be three rovers working on the planet’s surface with Curiosity and Perseverance – complete with Ingenuity – presently surveying Mars, too.

Insurance agents will not be gnashing their teeth in anticipation of a collision – they are all at different areas of Mars.

HOW DID IT GET THERE?

LAUNCHED by the China National Space Administration (CNSA) aboard a Long March rocket from the Wenchang space site on July 23 last year, the five-ton Tianwen-1 craft consisted of an orbiter, a deployable camera, a lander and Zhurong.

The journey from Earth to Mars was smooth and Tianwen-1 – the name means Heavenly Questions – entered Mars orbit in February. It spent three months observing the planet before sending down Zhurong to land on the vast relatively flat space of Utopia Planitia in the northern hemisphere of Mars.

It takes 18 minutes to receive a radio signal from Mars, so the CNSA controllers were “blind” as the lander went through what is called the “seven minutes of terror” as the craft plunged into the Martian atmosphere.

On the descent, a heat shield protected the lander which then deployed a parachute before firing mini-rockets a the last moment to slow the lander down for a soft landing on Mars. It was just 25 miles away from its target area – not bad after a journey of nearly 200 million miles.

Landing shortly after 7am Beijing time on Saturday, the scientists at CNSA had an anxious 18 minutes to wait until the lander made contact via the Tianwen-1 which is relaying Zhurong’s findings to Earth.

Zhurong is about 6 ft (1.83 m) tall and weighs 38stones (240 kgs). Its safe landing means that China has done what Russia and Europe could not do and put a wheeled vehicle on another planet.

The European Space Agency has tried twice unsuccessfully in the past decades. The Soviet Union also tried twice in the early 1970s at the height of the Cold War space race. Its Mars 2 probe crashed and its Mars 3 lander touched down in 1971, but survived only long enough to transmit a single image back to Earth.

WHAT IS ZHURONG GOING TO DO?

OVER the next 90 days or so – Mars has slightly longer days than ours at 24 hours and 39 minutes – the controllers at CNSA will direct the rover across the Utopia Planitia, thought to have been created by a massive comet or meteor. The vast basin is believed to have once been an ocean.

The rover will study Mars’s geological structure, the composition of its surface and underlying layers of rock and ice, its magnetic field and its climate.

Zhurong will be looking particularly for signs that water exists in the form of ice under the surface. It will use its six scientific instruments, including two panoramic cameras, a ground-penetrating radar and a magnetic field detector. The rover also has a laser that it will aim at rocks to study their composition, as well as a meteorological instrument to study the climate and weather on Mars.

It’s the laser which has got some scientists really excited as burrowing into rock might just find that life of some form once existed on Mars.

Long Xiao, a planetary scientist at the China University of Geosciences, told National Geographic: “Because the pre-selected landing site is close to an ancient ocean shoreline, and distinct from others, the science data will uncover more secrets of Mars.”

A GIANT STEP FORWARD FOR CHINA?

BEFORE the mission, CNSA wrote in the journal Nature Astronomy: “Tianwen-1 is going to orbit, land and release a rover all on the very first try. No planetary missions have ever been implemented in this way. If successful, it would signify a major technical breakthrough.”

It was certainly big enough for China’s President Xi Jinping to send a special message of congratulations to the CNSA team.

He said: “You were brave enough for the challenge, pursued excellence and placed our country in the advanced ranks of planetary exploration.”

For once that was no nationalist hyperbole, but quite true. China has slowly and methodically built a space programme to rival that of the USA and Russia, and is clearly ahead of Europe which has seen the European Space Agency hampered by Brexit – the UK remains a member but there have been problems.

Thomas Zurbuchen, the head of science at NASA, said: “Together with the global science community, I look forward to the important contributions this mission will make to humanity’s understanding of the Red Planet,” Dean Cheng, a research fellow in Chinese political and military affairs at the Washington-based think-tank, The Heritage Foundation, told the BBC that the successful landing of Zhuron would be an “enormous fillip” to the country.

He said: “From the Chinese perspective, space benefits Chinese diplomacy, Chinese technology; it’s a great advertisement; it reinforces the legitimacy of the Chinese Communist Party to its own people.

“Space always has military implications, and conversely, by going to Mars, it demonstrates that China can contribute to what they term the global pool of human knowledge.”

China also has hugely ambitious plans to send a spacecraft to Mars and have it return with rock samples.