China lands Jade Rabbit robot rover on Moon

By Paul Rincon Science editor, BBC News website

The lander has touched down on a flat plain known as Sinus Iridum, or the Bay of Rainbows

China says it has successfully landed a craft carrying a robotic rover on the surface of the Moon, a major step in its programme of space exploration.

On Saturday afternoon (GMT), a landing module underwent a powered descent, using thrusters to perform the first soft landing on the Moon in 37 years.

Several hours later, the lander will deploy a robotic rover called Yutu, which translates as "Jade Rabbit".
The touchdown took place on a flat plain called the Bay of Rainbows.

The mission launched on a Chinese-developed Long March 3B rocket on 1 December from Xichang in the country's south.

China's space mission team celebrate after the landing

The Chang'e-3 craft began its descent just after 1300 GMT (2100 Beijing time), with state television showing pictures of the moon's surface as the lander touched down.

Staff at mission control in Beijing were shown clapping and celebrating after confirmation came through. The official Xinhua news service reported that the spacecraft reached the surface at 1312 GMT after hovering above the surface for several minutes finding an appropriate place to land.
The probe's soft-landing was the most difficult task during the mission, Wu Weiren, the lunar programme's chief designer, told Xinhua.

It is the third robotic rover mission to land on the lunar surface, but the Chinese vehicle carries a more sophisticated payload, including ground-penetrating radar which will gather measurements of the lunar soil and crust.

 

"It's still a significant technological challenge to land on another world," said Peter Bond, consultant editor for Jane's Space Systems and Industry told the AP news agency. 

"You have to use rocket motors for the descent and you have to make sure you go down at the right angle and the right rate of descent and you don't end up in a crater on top of a large rock."
According to translated documents, the landing module was to actively reduce its speed at about 15km from the Moon's surface.

When it reached a distance of 100m from the surface, the craft fired thrusters to slow its descent.
At a distance of 4m, the lander switched off the thrusters and fell to the lunar surface.
The Jade Rabbit was expected to be deployed several hours after touchdown, driving down a ramp lowered by the landing module.

Reports suggest the lander and rover will photograph each other at some point on Sunday.

According to Chinese space scientists, the mission is designed to test new technologies, gather scientific data and build intellectual expertise.

"China's lunar program is an important component of mankind's activities to explore [the] peaceful use of space," said Sun Huixian, a space engineer with the Chinese lunar programme.

The 120kg (260lb) Jade Rabbit rover can reportedly climb slopes of up to 30 degrees and travel at 200m (660ft) per hour.

Its name - chosen in an online poll of 3.4 million voters - derives from an ancient Chinese myth about a rabbit living on the moon as the pet of the lunar goddess Chang'e.

Dean Cheng, a senior research fellow at the Heritage Foundation, a conservative think-tank in Washington DC, said China's space programme was a good fit with China's concept of "comprehensive national power". This might be described as a measure of a state's all-round capabilities.

Space exploration was, he told BBC News, "a reflection of your economic power, because you need spare resources to have a space programme. It clearly has military implications because so much space technology is dual use".

He added: "It reflects your scientific and technological capabilities, it supports your diplomacy by making you appear strong.

"China is saying: 'We are doing something that only two other countries have done before - the US and the Soviet Union."

The Chang'e-3 mission launches from Xichang, south China

Mr Cheng explained that the mission would provide an opportunity to test China's deep-space tracking and communications capability.

"The rover will reportedly be under Earth control at various points of its manoeuvres on the lunar surface," Mr Cheng wrote in a blog post.

"Such a space observation and tracking system has implications not only for space exploration but for national security, as it can be used to maintain space surveillance, keeping watch over Chinese and other nations' space assets."

China has been methodically and patiently building up the key elements needed for an advanced space programme - from launchers to manned missions in Earth orbit to unmanned planetary craft - and it is investing heavily.

The Jade Rabbit, seen in this artist's impression, is the first wheeled vehicle on the Moon since the 1970s

 

"China wants to go to the moon for geostrategic reasons and domestic legitimacy," Prof Joan Johnson-Freese, of the US Naval War College in Rhode Island, told the AFP news agency.
"With the US exploration moribund at best, that opens a window for China to be perceived as the global technology leader - though the US still has more, and more advanced, assets in space."
The lander's target is Sinus Iridum (Latin for Bay of Rainbows) a flat volcanic plain thought to be relatively clear of large rocks. It is part of a larger feature known as Mare Imbrium that forms the right eye of the "Man in the Moon".

After this, a mission to bring samples of lunar soil back to Earth is planned for 2017. And this may set the stage for further robotic missions, and - perhaps - a crewed lunar mission in the 2020s.
"[Chang'e-3] is probably laying some of the groundwork for a manned mission," said Mr Cheng.