The prequel of lunar rover Yutu

When Chinese space technologists began drawing the blueprint for China's first moon rover, Yutu, or Jade Rabbit, some of their ideas were straight out of science fiction.

Would it be a four-wheeled, six-wheeled or eight-wheeled rover with rectangular, triangular or trapezoid shaped solar panels?

What emerged was the condensed wisdom and diligence of hundreds of researchers who spent a decade in its design and production.

CONCEPTION

In July 2004, Jia Yang, a researcher with the China Academy of Space Technology (CAST), drew three overlapping circles, representing spacecraft, vehicle and robot.

"The moon rover concept was at the intersection of the three circles. The biggest difference between a moon rover and other spacecraft was that it would interact with the moon's surface," Jia recalls.

At the start of China's Chang'e lunar exploration program in 2004, more than a dozen research institutes and universities vied to take part in the development of the lunar rover. They had many designs. Some moved fast; some had deft robotic arms; some could overcome big obstacles.

Eventually, more than 100 institutes and research agencies joined the project and the lunar rover was a combination of technologies from various sectors, says Jia, who became deputy chief designer of the Chang'e-3 lunar probe in 2008.

"We studied many foreign documents to understand the basic research. But when we met difficulties, we could only rely on ourselves," Jia says.

According to fellow deputy chief designer Zhang Yuhua, of Shanghai Academy of Spaceflight Technology, no cooperation was carried out between China and the United States in lunar exploration.

FUNCTION OVER LOOKS

On the initial blueprint, the body of the moon rover was a cube-like box. Some critics likened it to an ice-cream vendor's trolley.

The designers created many new shapes, but chose the most feasible in terms of technology.

"Since we had many restrictions, such as the weight, we kept the design simple to meet all the functional demands," says Jia.

"Maybe some thought the moon rover was not pretty, but it was perfect in our eyes because it met all the technological requirements."

The designs at different stages reflect the evolution. The rover's body transformed from a box to a complicated shape enveloped by cooling panels; the wheels were connected in different ways; the formerly foldable solar panels on each side became one foldable, one fixed; the antenna and the pole holding the cameras were combined.