Chang'e probe moves to within 15km of lunar surface
Spacecraft successfully fires thrusters to reduce orbit ahead of planned touchdown of country's first moon lander and rover over the weekend
The lunar probe Chang'e-3 has shifted its orbit, moving closer to the moon ready for its landing scheduled on Saturday, state media reported.
The craft changed from a circular to an elliptical orbit, which took its distance to the lunar surface from 100 kilometres to as little as 15 kilometres, Xinhua said. The manoeuvre was conducted when Chang'e-3 was on the dark side of the moon and could not be seen directly from earth.
The probe fired its thrusters automatically and when it reemerged on the radar of Beijing's flight control it was flying precisely on the new elliptical orbit as programmed.
The country's space authorities have also revealed more information about the devices that will be critical to a successful landing on the lunar surface.
Wu Ji , chief payload scientist, told Xinhua a landing camera would be activated when the probe was about two kilometres above the moon to determine the best spot for its descent.
It will also beam back to earth the images of the first landing on a celestial body by a Chinese spacecraft.
"Though the landing camera will work only a few minutes and take only dozens of images, these will be very important to the study of the lunar landscape and route planning for the rover," he said.
Those images will have been made possible in part thanks to a Hongkonger - Yung Kai-leung, an engineering professor at Polytechnic University, developed the structure that holds the camera and allows it to move.
Watch: 3D animation of how the rover works
Chang'e-3 would take control of the touchdown, the Science and Technology Daily, a newspaper under the control of the Ministry of Science and Technology, reported.
Space authorities would not intervene and would allow the probe to calculate where to land and adjust the speed of its descent to the lunar surface, the newspaper said.
The landing vehicle can touch down anywhere within an area about half the size of a soccer pitch at a speed of lower than four metres per second.
To absorb the force of impact, the probe has been equipped with strong suspension in its four legs. Scientists also gave the probe feet the shape and size of a wash basin to achieve maximum stability after landing.
If the landing succeeds, it will be the first probe to touch down on the moon since a Russian craft in 1976. Other missions since then have crashed probes into the lunar surface.
The probe features a lander and the solar-powered robotic rover, called Yutu, or Jade Rabbit, which will carry out geological surveys and astronomical observations for three months.
It would be the first rover to operate on the moon since 1973.