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Chinese lunar probe Chang’e-3 has entered into a new phase of space exploration after successfully landing on the Earth’s satellite.
The soft landing was made at approximately 9：11 p.m.， Beijing time， 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， called Sinus Iridum， or the Bay of Rainbows， has remained untouched until now.
About seven hours after the landing， at 4：35 a.m.， Beijing time， on December 15， Yutu， or 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 the Earth， according to the Beijing Aerospace Control Center.
At 11：42 p.m.， after the rover moved to a spot about 9 meters north to 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 Chinese flag， the first time that the five-starred red flag had 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.
“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 begun observing space， the Earth and the Moon， as of December 18.
Previously unseen
“Chang’e-3 will study the Moon’s terrain， geological structure， composition， and potentially exploitable resources，” said Zou Yongliao， a space 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 humankind 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， with a three-month designed life span， will survey the Moon’s geological structure and surface substances and look for natural resources.
On night of December 15， Yutu’s radar began tests to determine the constitution of 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 a low speed for the vehicle because it has to detect and avoid obstacles.
Using its ability to detect obstacles， the rover will determine a 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 had 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 minus 180 degrees Celsius 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 minus 40 degrees Celsius to 50 degrees Celsius. To achieve this， both the lander and rover are equipped with radioisotope heating units.
Technological breakthroughs
Before Chang’e-3 landed on the Moon， 129 lunar explorations had been conducted but only 66 of them succeeded， among which only 13 unmanned soft landings were successfully completed.
The last soft landing took place on August 18， 1976， when the Soviet probe Luna-24 touched down on the Moon to collect samples.
The low success rate tells the difficulties of lunar explorations and landing. China， as a newcomer to the world’s space exploration club， has been adhering to a path of domestically developed innovations.
Compared to Chang’e-1 and Chang’e-2 lunar probes， launched in 2007 and 2010 respectively， 80 percent of Chang’e-3’s components and technologies are new， said Sun Zezhou， chief designer of the lunar probe. Launched in January 2004， China’s lunar exploration program includes orbiting and landing on the moon and returning to the Earth.
After the Chang’e-3 mission， China’s lunar exploration program will enter a new stage of unmanned automatic sampling and return when it launches Chang’e-5， which will be an even more difficult endeavor with its own new challenges.
“The program’s third phase will be more difficult because many technological breakthroughs must be made first， such as takeoff from the lunar surface， sampling encapsulation， rendezvous and docking in lunar orbit， and high-speed Earth re-entry， which are all new to China，” said Wu Zhijian， a spokesman for the State Administration of Science， Technology and Industry for National Defense， at a press conference in Beijing on December 16.
As the backup probe from Chang’e-3， Chang’e-4 will also be adapted to test technologies to be used by Chang’e-5， according to Wu.
It was revealed that China plans to launch Chang’e-5 in 2017， which is expected to bring back up to 2 kg of material from the lunar surface.
Global cooperation
Researchers from the U.S. National Aeronautics and Space Administration （NASA） have described Chang’e-3’s operations on the Moon as “a new scientific opportunity that could potentially enhance studies and observations of the lunar atmosphere.”
“The Chang’e-3 details tell me that the United States now absolutely must start communicating with the Chinese about lunar cooperation，” said U.S. astronaut Buzz Aldrin， who was the second man to set foot on the Moon after Neil Armstrong， in an interview with Aerospace America magazine.
Russian astronaut Vladimir Kovalenok said that the Chinese lunar program is on the right track and China can continue its path while taking into account the pros and cons of the lunar programs of the United States and the former Soviet Union.
“China is now a pioneer in this field， and its lunar missions will be a catalyst for lunar explorations by other countries， as the Moon can serve as a basis for a ‘jump’ on journeys to more distant places in the solar system，” Kovalenok said.
“The European Space Agency （ESA） and China have recently signed a mutual cross support agreement that implies that the ESA can provide support to a Chinese mission through our deep space network （Estrack），” said Karl Bergquist， Administrator of ESA’s International Relations Department. “But the contrary could also be possible， i.e. that ESA would request China to use the Chinese deep space antennas for an ESA mission. This has not yet happened， but I am sure it will happen in the next few years，” Bergquist told China’s Xinhua News Agency.
At the December 16 press conference， Wu said that China is always positive about international cooperation in lunar exploration. “We have had great cooperation with other countries and international organizations during previous missions，” he noted.
Data collected through Chang’e-1 and Chang’e-2 probes are available to scientists across the globe， according to Wu. He also revealed that China shared information collected by Chang’e-1 with the ESA， and an ESA aerospace control center and three of its telecommand telemetry control stations took part in the Chang’e-3 mission.
“In the next stage of China’s lunar exploration program， there will be more international cooperation，” Wu said.
The soft landing was made at approximately 9：11 p.m.， Beijing time， 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， called Sinus Iridum， or the Bay of Rainbows， has remained untouched until now.
About seven hours after the landing， at 4：35 a.m.， Beijing time， on December 15， Yutu， or 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 the Earth， according to the Beijing Aerospace Control Center.
At 11：42 p.m.， after the rover moved to a spot about 9 meters north to 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 Chinese flag， the first time that the five-starred red flag had 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.
“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 begun observing space， the Earth and the Moon， as of December 18.
Previously unseen
“Chang’e-3 will study the Moon’s terrain， geological structure， composition， and potentially exploitable resources，” said Zou Yongliao， a space 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 humankind 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， with a three-month designed life span， will survey the Moon’s geological structure and surface substances and look for natural resources.
On night of December 15， Yutu’s radar began tests to determine the constitution of 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 a low speed for the vehicle because it has to detect and avoid obstacles.
Using its ability to detect obstacles， the rover will determine a 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 had 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 minus 180 degrees Celsius 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 minus 40 degrees Celsius to 50 degrees Celsius. To achieve this， both the lander and rover are equipped with radioisotope heating units.
Technological breakthroughs
Before Chang’e-3 landed on the Moon， 129 lunar explorations had been conducted but only 66 of them succeeded， among which only 13 unmanned soft landings were successfully completed.
The last soft landing took place on August 18， 1976， when the Soviet probe Luna-24 touched down on the Moon to collect samples.
The low success rate tells the difficulties of lunar explorations and landing. China， as a newcomer to the world’s space exploration club， has been adhering to a path of domestically developed innovations.
Compared to Chang’e-1 and Chang’e-2 lunar probes， launched in 2007 and 2010 respectively， 80 percent of Chang’e-3’s components and technologies are new， said Sun Zezhou， chief designer of the lunar probe. Launched in January 2004， China’s lunar exploration program includes orbiting and landing on the moon and returning to the Earth.
After the Chang’e-3 mission， China’s lunar exploration program will enter a new stage of unmanned automatic sampling and return when it launches Chang’e-5， which will be an even more difficult endeavor with its own new challenges.
“The program’s third phase will be more difficult because many technological breakthroughs must be made first， such as takeoff from the lunar surface， sampling encapsulation， rendezvous and docking in lunar orbit， and high-speed Earth re-entry， which are all new to China，” said Wu Zhijian， a spokesman for the State Administration of Science， Technology and Industry for National Defense， at a press conference in Beijing on December 16.
As the backup probe from Chang’e-3， Chang’e-4 will also be adapted to test technologies to be used by Chang’e-5， according to Wu.
It was revealed that China plans to launch Chang’e-5 in 2017， which is expected to bring back up to 2 kg of material from the lunar surface.
Global cooperation
Researchers from the U.S. National Aeronautics and Space Administration （NASA） have described Chang’e-3’s operations on the Moon as “a new scientific opportunity that could potentially enhance studies and observations of the lunar atmosphere.”
“The Chang’e-3 details tell me that the United States now absolutely must start communicating with the Chinese about lunar cooperation，” said U.S. astronaut Buzz Aldrin， who was the second man to set foot on the Moon after Neil Armstrong， in an interview with Aerospace America magazine.
Russian astronaut Vladimir Kovalenok said that the Chinese lunar program is on the right track and China can continue its path while taking into account the pros and cons of the lunar programs of the United States and the former Soviet Union.
“China is now a pioneer in this field， and its lunar missions will be a catalyst for lunar explorations by other countries， as the Moon can serve as a basis for a ‘jump’ on journeys to more distant places in the solar system，” Kovalenok said.
“The European Space Agency （ESA） and China have recently signed a mutual cross support agreement that implies that the ESA can provide support to a Chinese mission through our deep space network （Estrack），” said Karl Bergquist， Administrator of ESA’s International Relations Department. “But the contrary could also be possible， i.e. that ESA would request China to use the Chinese deep space antennas for an ESA mission. This has not yet happened， but I am sure it will happen in the next few years，” Bergquist told China’s Xinhua News Agency.
At the December 16 press conference， Wu said that China is always positive about international cooperation in lunar exploration. “We have had great cooperation with other countries and international organizations during previous missions，” he noted.
Data collected through Chang’e-1 and Chang’e-2 probes are available to scientists across the globe， according to Wu. He also revealed that China shared information collected by Chang’e-1 with the ESA， and an ESA aerospace control center and three of its telecommand telemetry control stations took part in the Chang’e-3 mission.
“In the next stage of China’s lunar exploration program， there will be more international cooperation，” Wu said.