China over the Moon

　　Chinese lunar probe Chang’e-3 has entered into anew phase of space exploration after successfully landingon the Earth’s satellite.

　　The soft landing was made at approximately 9：11 p.m.，Beijing time， on December 14， making China the thirdcountry to do so after the former Soviet Union and theUnited States. Chang’e-3 was launched on a Long March-3Bcarrier rocket from the Xichang Satellite Launch Centerin southwest China’s Sichuan Province. The region of theMoon that the probe landed on， called Sinus Iridum， or theBay of Rainbows， has remained untouched until now.

　　About seven hours after the landing， at 4：35 a.m.， Beijingtime， on December 15， Yutu， or Jade Rabbit， the 140-kglunar rover carried by Chang’e-3， separated from the landerand drove out onto the Moon’s surface， leaving behind tiretracks on the loose lunar soil. A camera on the lander recordedthe process and the images were transmitted backto the Earth， according to the Beijing Aerospace ControlCenter.

　　At 11：42 p.m.， after the rover moved to a spot about9 meters north to the lander， they took photographs ofeach other using the lander’s landform camera and Yutu’spanoramic camera.

　　The color images， transmitted live via a satellite networkdesigned by China， show Yutu proudly brandishing theChinese flag， the first time that the five-starred red flag hadbeen taken to an extraterrestrial body.

　　Ma Xingrui， chief commander of China’s lunar explorationprogram， announced that the Chang’e-3 mission was a“complete success，” after the lander and moon rover tookpictures of each other.

　　“The photographs showed both the lander and the roverare functioning well and at the same time they marked thecompletion of the soft landing， and the beginning of onsitesurveying，” said Pei Zhaoyu， a spokesman for the program.According to scientists working on the Chang’e-3mission， six of the eight scientific instruments aboardYutu and the Chang’e-3’s lander have already beenactivated and begun observing space， the Earthand the Moon， as of December 18.

　　Previously unseen

　　“Chang’e-3 will study the Moon’s terrain， geologicalstructure， composition， and potentiallyexploitable resources，” said Zou Yongliao， aspace scientist with the Chinese Academy ofSciences， adding that the lander will observethe Earth’s plasmasphere using an extremeultravioletimager.

　　At the same time， theChang’e-3’s lander， which willconduct exploration at thelanding site for one year， willalso deploy a telescope thatwill observe deep space.

　　“This is the first timehumankind has placed atelescope on the Moon. Thespecial environment of theMoon will enable us to conductobservation that couldnot be done on the Earth dueto the impact of the atmosphere，” said Sun Huixian， deputychief engineer of China’s lunar exploration program.

　　Yutu， with a three-month designed life span， will surveythe Moon’s geological structure and surface substancesand look for natural resources.

　　On night of December 15， Yutu’s radar began tests todetermine the constitution of lunar soil. According to Sun，the radar system attached to the bottom of the rover canscan up to 100 meters beneath the lunar surface.

　　Sun said that the rover is able to climb slopes of up to30 degrees and travel at 200 meters per hour， explainingthat designers set a low speed for the vehicle because ithas to detect and avoid obstacles.

　　Using its ability to detect obstacles， the rover will determinea path of least resistance by coupling its onboardnavigation systems with remote control.

　　“Theoretically， Yutu can travel nearly 10 km across theMoon，” Sun said. “Engineers had set up a laboratory on theEarth to simulate the uneven terrain of the Moon and therover went through extensive testing first.”

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

　　To work properly， the rover has to maintain aninternal operating temperature range betweenminus 40 degrees Celsius to 50 degrees Celsius.To achieve this， both the lander and rover areequipped with radioisotope heating units.

　　Technological breakthroughs

　　Before Chang’e-3 landed on the Moon， 129 lunarexplorations had been conducted but only66 of them succeeded， among which only 13 unmannedsoft landings were successfully completed.

　　The last soft landing took place on August 18， 1976， whenthe Soviet probe Luna-24 touched down on the Moon tocollect samples.

　　The low success rate tells the difficulties of lunar explorationsand landing. China， as a newcomer to the world’s spaceexploration club， has been adhering to a path of domesticallydeveloped innovations.

　　Compared to Chang’e-1 and Chang’e-2 lunar probes，launched in 2007 and 2010 respectively， 80 percent ofChang’e-3’s components and technologies are new， said SunZezhou， chief designer of the lunar probe.

　　Launched in January 2004， China’s lunar explorationprogram includes orbiting and landing on the moon andreturning to the Earth.

　　After the Chang’e-3 mission， China’s lunar explorationprogram will enter a new stage of unmanned automaticsampling and return when it launches Chang’e-5， which willbe an even more difficult endeavor with its own new challenges.

　　“The program’s third phase will be more difficult becausemany technological breakthroughs must be made first， suchas takeoff from the lunar surface， sampling encapsulation，rendezvous and docking in lunar orbit， and high-speedEarth re-entry， which are all new to China，” said Wu Zhijian， aspokesman for the State Administration of Science， Technologyand Industry for National Defense， at a press conferencein Beijing on December 16.

　　As the backup probe from Chang’e-3， Chang’e-4 will alsobe 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 in2017， which is expected to bring back up to 2 kg of materialfrom the lunar surface.

　　Global cooperation

　　Researchers from the U.S. National Aeronautics and SpaceAdministration (NASA) have described Chang’e-3’s operationson the Moon as “a new scientific opportunity that couldpotentially enhance studies and observations of the lunaratmosphere.”

　　“The Chang’e-3 details tell me that the United Statesnow absolutely must start communicating with the Chineseabout lunar cooperation，” said U.S. astronaut Buzz Aldrin，who was the second man to set foot on the Moon afterNeil Armstrong， in an interview with Aerospace Americamagazine.

　　Russian astronaut Vladimir Kovalenok said that theChinese lunar program is on the right track and China cancontinue its path while taking into account the pros andcons of the lunar programs of the United States and theformer Soviet Union.

　　“China is now a pioneer in this field， and its lunar missionswill be a catalyst for lunar explorations by other countries，as the Moon can serve as a basis for a ‘jump’ on journeys tomore distant places in the solar system，” Kovalenok said.

　　“The European Space Agency (ESA) and China haverecently signed a mutual cross support agreement thatimplies that the ESA can provide support to a Chinesemission through our deep space network (Estrack)，” saidKarl Bergquist， Administrator of ESA’s International RelationsDepartment.

　　“But the contrary could also be possible， i.e. that ESAwould request China to use the Chinese deep space antennasfor an ESA mission. This has not yet happened， but Iam sure it will happen in the next few years，” Bergquist toldChina’s Xinhua News Agency.

　　At the December 16 press conference， Wu said thatChina is always positive about international cooperation inlunar exploration. “We have had great cooperation with othercountries and international organizations during previousmissions，” he noted.

　　Data collected through Chang’e-1 and Chang’e-2 probesare available to scientists across the globe， according to Wu.

　　He also revealed that China shared information collectedby Chang’e-1 with the ESA， and an ESA aerospace controlcenter and three of its telecommand telemetry control stationstook 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.