China on the Moon

TOUCHDOWN: Chang'e-3 probe's soft-landing on the lunar surface on December 14 is shown on a monitor in the Beijing Aerospace Control Center (LI XIN)

The Chinese lunar probe Chang'e-3 has initiated a new phase of space exploration for mankind after successfully landing on the Earth's satellite.

The soft-landing was made at approximately 9:11 p.m. on December 14, making China the third country to do so after the former Soviet Union and the United States. Chang'e-3 was launched on a Long March-3B carrier rocket from the Xichang Satellite Launch Center in southwest China's Sichuan Province. The region of the moon that the probe landed on, known as Sinus Iridum, or the Bay of Rainbows, has remained unstudied and untouched by mankind until now.

About seven hours after the landing, at 4:35 a.m. on December 15, Yutu, meaning jade rabbit, the 140-kg lunar rover carried by Chang'e-3, separated from the lander and drove out onto the moon's surface, leaving behind tire tracks on the loose lunar soil. A camera on the lander recorded the process and the images were transmitted back to Earth, according to the Beijing Aerospace Control Center.

At 11:42 p.m., after the rover moved to a spot about nine meters north of the lander, they took photographs of each other using the lander's landform camera and Yutu's panoramic camera.

The color images, transmitted live via a satellite network designed by China, show Yutu proudly brandishing the five-starred red Chinese flag, the first time that it has been taken to an extraterrestrial body.

Ma Xingrui, chief commander of China's lunar exploration program, announced that the Chang'e-3 mission was a "complete success," after the lander and moon rover took pictures of each other.

Previously unseen

"The photographs showed both the lander and the rover are functioning well and at the same time they marked the completion of the soft landing, and the beginning of onsite surveying," said Pei Zhaoyu, a spokesman for the program.

According to scientists working on the Chang'e-3 mission, six of the eight scientific instruments aboard Yutu and the Chang'e-3's lander have already been activated and have begun observing space, the Earth and the moon, as of December 18.

"Chang'e-3 will study the moon's terrain, geological structure, composition, and potentially exploitable resources," said Zou Yongliao, a scientist with the Chinese Academy of Sciences, adding that the lander will observe the Earth's plasmasphere using an extreme-ultraviolet imager.

At the same time, the Chang'e-3's lander, which will conduct exploration at the landing site for one year, will also deploy a telescope that will observe deep space.

"This is the first time mankind has placed a telescope on the moon. The special environment of the moon will enable us to conduct observation that could not be done on the Earth due to the impact of the atmosphere," said Sun Huixian, deputy chief engineer of China's lunar exploration program.

Yutu, which will have a three-month life span, will survey the moon's geological structure and surface composition, also looking for natural resources.

On December 15, Yutu's radar began tests to determine the constitution of the lunar soil. According to Sun, the radar system attached to the bottom of the rover can scan up to 100 meters beneath the lunar surface.

Sun said that the rover is able to climb slopes of up to 30 degrees and travel at 200 meters per hour, explaining that designers set such a low speed for the vehicle because it has to detect and avoid obstacles.

Using its ability to detect obstructions, the rover will determine the path of least resistance by coupling its onboard navigation systems with remote control.

"Theoretically, Yutu can travel nearly 10 km across the moon," Sun said. "Engineers set up a laboratory on the Earth to simulate the uneven terrain of the moon and the rover went through extensive testing first."

The moon's temperature ranges from more than 100 degrees Celsius during the day to as low as 180 degrees Celsius below zero at night due to the lack of an atmosphere, presenting another challenge to the rover.

To work properly, the rover has to maintain an internal operating temperature range between 40 degrees Celsius below zero to 50 degrees Celsius above. To achieve this, both the lander and rover are equipped with radioisotope heating units.