A concept of China's moon lander, via China.com.cn
There are rumblings around the Internets that China is getting ready to join the elite club of nations with rovers on other worlds. Yes, China is headed for the Moon.
China’s Chang'E 3 spacecraft is a nuclear powered lander that will carry a small rover to the lunar surface. And while details are a little scarce for the time being, it looks like the mission could launch by the end of the year.
After launching on one of the nation’s Long March rockets and a three-day transit, Chang'E 3 will reach the Moon and enter into a 62 mile orbit. Once settled, the 2,645 pound lander will separate from the roughly 8,200 pound spacecraft and descend into a highly elliptical orbit 62 by 9.5 miles above the surface.
Another view of the rover atop the lander.
From its low point, the lander will fire its thrusters and slowly descend towards the surface, stopping to hover at about 330 feet. At this point it will engage its autonomous hazard avoidance system and move around horizontally to look for a nice smooth place to land. With the right point found, the lander will fire its thrusters again. Once it’s just 14 feet above the surface, the engines will cut out and it will fall, relatively gently thanks to low gravity, to the surface and begin its year long mission – the lander’s operational lifetime is given as 12 lunar days.
The Chang'E 3 lander will rely on a plutonium-238 radioisotope thermoelectric generator, or RTG, for power. This is the same type of unit that’s currently powering Curiosity’s traverse across Mars. But unlike Curiosity, Chang'E 3 will only use its RTG to keep the spacecraft’s systems humming during the two-week long lunar nights. Solar panels will allow the lander to take advantage of the free power during the two-week long lunar days.
But the mission’s real pièce de résistance is the 220 pound rover. Like all rovers we’ve seen explore the solar system, this one will be controlled from Earth. It will rove within its operational range of about 6 miles. Armed with a small payload of science instruments, the rover will survey the lunar territory and asses the environment during its three-month operational lifetime. But roving isn’t China’s ultimate goal in lunar exploration. Chang'E 3 is a step towards a sample return mission.
Shenzou-8 on the launch pad, via DLR
China’s history in space is a complicated one linked to its former cooperation with the Soviet Union. Under the Sino-Soviet treated in the 1960s, the USSR supplied China with the missile technology that serves as the foundation of its current launch systems. But spaceflight never got a firm start in China the way it did elsewhere. After the nation successfully but a satellite in lunar orbit in 1970, the focus shifted to manned spaceflight, an endeavor it couldn’t sustain through political, social, and economic stresses. Not until 2004 was China’s lunar exploration program restarted. The spacecraft, Chang’E, is named for the Moon god in ancient Chinese mythology.
The first launches were orbital reconnaissance missions; Chang'E 1 launched on 24 October 2007 and Chang'E 2 launched on 1 October 2010. Chang'E 3 is the first mission in the soft-landing phase of the program, a mission profile that will likely be repeated on Chang'E 4. Chang'E 5 and Chang'E 6 are slated to begin the sample return phase of China’s lunar exploration.
These will be Apollo-style missions with an ascent vehicle launching the sample from the surface and rendezvousing with an Earth return spacecraft in lunar orbit. The goal is to collect and recover about 4.5 pounds of material. But sending the necessary hardware to the Moon for a sample return mission will require a brand new rocket, the Long March 5, which is scheduled to begin flying sometime late next year. For a visual on these proposed missions, check out Emily Lakdawalla of the Planetary Society's dedicated Flickr album.
Of course, this plan could still change–news from the tight-lipped Chinese space authority can be hard to come by for English speakers. Either way, the prospect of a sample return mission is exciting. It's also way less likely to spark some new space race than, say, a mission to have taikonauts collect and return samples by hand.