China’s Chang’e-3 Moon Rover Descends to Lower Orbit Sets Up Historic Soft Landing

by Ken Kremer on December 13, 2013

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China's lunar probe Chang'e-3 is expected to land on Sinus Iridum (Bay of Rainbows) of the moon in mid-December 2013. Credit: Xinhua

China’s lunar probe Chang’e-3 is expected to land on Sinus Iridum (Bay of Rainbows) of the Moon in mid-December 2013. Credit: Xinhua

All systems appear to be “GO” for the world’s first attempt to soft land a space probe on the Moon in nearly four decades.

China’s maiden moon landing probe – Chang’e-3 – is slated to attempt the history making landing this weekend on a lava plain in the Bay of Rainbows, or Sinus Iridum region.

Chinese space engineers at the Beijing Aerospace Control Center (BACC) paved the way for the historic touchdown by successfully commanding Chang’e-3 to descend from the 100 km-high lunar circular orbit it reached just one week ago on Dec. 6, to “an elliptical orbit with its nearest point about 15 km away from the moon’s surface”, according to a statement from China’s State Administration of Science, Technology and Industry for National Defense (SASTIND).

UPDATE: CCTV is providing live landing coverage

The first pictures taken from the alien lunar surface in some 37 years are expected to be transmitted within days or hours of touchdown planned as early as Saturday, Dec. 14, at 9:40 p.m. Beijing local time, 8:40 a.m. EST.

CCTV, China’s state run network, carried the launch live. It remains to be seen whether they will have live coverage of the landing since there have been no programming announcements.

SASTIND said the orbit lowering thruster firing was “conducted above the dark side of the moon at 9:20 p.m.” on Dec. 10, Beijing local time.

Confirmation of the Chang’e-3 probes new, lower orbit was received four minutes later.

China's lunar probe Chang'e-3 entered an orbit closer to the moon on Dec. 10, 2013. (Xinhua)

China’s lunar probe Chang’e-3 entered an orbit closer to the moon on Dec. 10, 2013. Credit: Xinhua

If successful, the Chang’e-3 mission will mark the first soft landing on the Moon since the Soviet Union’s unmanned Luna 24 sample return vehicle landed back in 1976.

China would join an elite club of three, including the United States, who have mastered the critical technology to successfully touch down on Earth’s nearest neighbor.

The Chang’e-3 mission is comprised of China’s ‘Yutu’ lunar lander riding piggyback atop a much larger four legged landing probe.

Artists concept of the Chinese Chang'e 3 lander and rover on the lunar surface.  Credit: Beijing Institute of Spacecraft System Engineering

Artists concept of the Chinese Chang’e-3 lander and rover on the lunar surface. Credit: Beijing Institute of Spacecraft System Engineering

The voyage from the Earth to the Moon began 12 days ago with the flawless launch of Chang’e-3 atop China’s Long March 3-B booster at 1:30 a.m. Beijing local time, Dec. 2, 2013 (12:30 p.m. EST, Dec. 1) from the Xichang Satellite Launch Center, in southwest China.

Chang’e-3 will make a powered descent to the Moon’s surface on Dec. 14 by firing the landing thrusters at the altitude of 15 km (9 mi) for a soft landing in a preselected area on the Bay of Rainbows.

The powered descent will take about 12 minutes.

The variable thrust engine can continuously vary its thrust power between 1,500 to 7,500 newtons, according to Xinhua.

The Bay of Rainbows is located in the upper left portion of the moon as seen from Earth. It was imaged in high resolution by China’s prior lunar mission – the Chang’e-2 lunar orbiter.

The 1200 kg lander is equipped with terrain recognition equipment and software to avoid rock and boulder fields that could spell catastrophe even in the final seconds before touchdown if the vehicle were to land directly on top of them.

Chang’e-3 is powered by a combination of solar arrays and a nuclear device in order to survive the two week long lunar nights.

The six-wheeled ‘Yutu’ rover, with a rocker bogie suspension, will be lowered in stages to the moon’s surface in a complex operation and then drive off a pair of landing ramps to explore the moon’s terrain.

Yutu measures 150 centimeters high and weighs approximately 120 kilograms and sports a robotic arm equipped with science instruments.

The rover and lander are equipped with multiple cameras, spectrometers, an optical telescope, ground penetrating radar and other sensors to investigate the lunar surface and composition.

The radar instrument installed at the bottom of the rover can penetrate 100 meters deep below the surface to study the Moon’s structure and composition in unprecedented detail.

China’s Chang’e-3 probe joins NASA’s newly arrived LADEE lunar probe which entered lunar orbit on Oct. 6 following a spectacular night time blastoff from NASA’s Wallops Flight Facility in Virginia.

Stay tuned here for Ken’s continuing Chang’e-3, LADEE, MAVEN, MOM, Mars rover and more news.

Ken Kremer

About 

Dr. Ken Kremer is a speaker, scientist, freelance science journalist (Princeton, NJ) and photographer whose articles, space exploration images and Mars mosaics have appeared in magazines, books, websites and calanders including Astronomy Picture of the Day, NBC, BBC, SPACE.com, Spaceflight Now and the covers of Aviation Week & Space Technology, Spaceflight and the Explorers Club magazines. Ken has presented at numerous educational institutions, civic & religious organizations, museums and astronomy clubs. Ken has reported first hand from the Kennedy Space Center, Cape Canaveral and NASA Wallops on over 40 launches including 8 shuttle launches. He lectures on both Human and Robotic spaceflight - www.kenkremer.com. Follow Ken on Facebook and Twitter

Olaf2 December 13, 2013 at 8:09 PM

Thumbs up! Very exciting.

Finally new images from the Moon’s surface closeup.

NilsErik Larsson December 13, 2013 at 8:47 PM

“The DARK Side of the Moon”?? Are we back in Jules Verne’s novel?

IVAN3MAN_AT_LARGE December 13, 2013 at 9:10 PM

Maybe Ken is a fan of Pink Floyd…?

Olaf2 December 13, 2013 at 10:10 PM

Right now that part is pretty dark when they fired that thruster. The intention is to land on that day side. It is no point in landing in a pitch dark place.

delphinus100 December 13, 2013 at 10:28 PM

Then they should have said ‘the nighttime side of the Moon.’

‘Dark Side’ tends to perpetuate the erroneous idea of an always-dark hemisphere that we can’t see…

MeMyselfAndI December 14, 2013 at 1:24 PM

Actually they should have said “the far side of the moon”

savuporo December 14, 2013 at 12:36 AM

It’s widely misreported in the press that Chang’e is “powered” by a nuclear device – it does not have a generator ( RTG ) but a radioisotope heater unit ( RHU )

irtesam December 14, 2013 at 3:03 AM

Great Job!!! Chinese are actually true landers and voyagers of Moon

Damir Vr?uka December 14, 2013 at 6:38 AM

???

UFOsMOTHER December 14, 2013 at 4:28 PM

Well done China, A truly Huge Step in the right direction, Super Effort 10 out of 10,,,,,

UFOsMOTHER December 14, 2013 at 4:35 PM

Outstanding well done China we are all waiting for the images to come,Giant Step in the Right Direction

William Sparrow December 14, 2013 at 9:36 PM

Relax, it’s a worthy accomplishment, but let’s not act like the Chinese are some sort of space pioneers. The U.S. put men on the moon 44 years ago, so a bit of context, please.

anonymous December 15, 2013 at 2:56 AM

hoax! no star… just like the same 43 years ago.

?? ? December 15, 2013 at 4:06 AM

It is just a small step in Chinese aerospace.

William Sparrow December 16, 2013 at 12:38 AM

Please, just go away……

Andreas Moser December 17, 2013 at 4:37 AM

But the Chinese moon landing has already been revealed as a fake: http://andreasmoser.wordpress.com/2013/12/17/chinese-moon-landing-is-fake/

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