China's 1st Moon Rover Arrives in Lunar Orbit
Less
than five days after leaving Earth atop a blazing Long March launcher,
China's Chang'e 3 spacecraft reached lunar orbit Friday to prepare for
an historic rocket-assisted touchdown in the moon's Bay of Rainbows
later this month.
Outfitted
with a six-wheeled robotic rover and smarts to avoid hazards in the
landing zone, Chang'e 3 is China's boldest unmanned space mission to
date, extending feats achieved by a pair of lunar orbiters launched in
2007 and 2010.
The four-legged lander fired its propulsion system
for six minutes and braked into orbit around the moon at 0953 GMT (4:53
a.m. EST) Friday, according to China's state-run Xinhua news agency. [How China's Chang'e 3 Moon Rover Works (Infographic)]
The craft lifted off Dec. 1 on a Long March 3B rocket, which put the probe on a direct four-and-a-half day trajectory from Earth to the moon.
The spacecraft is now flying 100 kilometers, or about 60 miles, above the moon, Xinhua reported.
After lowering its altitude later this week, Chang'e 3
will fire a variable-thrust main engine to make a soft landing in the
Bay of Rainbows, a dark lava plain on the upper-left quadrant of the
moon's near side.
The
lander has terrain recognition sensors to feed information into the
probe's guidance computer, ensuring the spacecraft does not come down on
a steep slope or in a boulder field.
A
few feet above the moon, the lander will autonomously cut off its
engine and drop to the surface. Engineers fastened shock absorbers to
the landing legs to cushion the impact.
China has not disclosed the time of the landing,
but European Space Agency officials supporting the mission with
communications and tracking antennas say the touchdown is scheduled for
some time Dec. 14.
Named
Yutu or "jade rabbit," the mission's rover will drive off the landing
platform a few hours later, according to ESA officials.
The
rover has a mass of 140 kilograms, or about 308 pounds, and carries
radioisotope heater units to keep the spacecraft warm during the two
week-long lunar nights. The heaters are likely powered by small
quantities of plutonium-238, the isotope of plutonium preferred for
space missions, according to respected space researcher Dwayne Day, who
discussed the rover's heaters in a story published in the Space Review.
The
Yutu rover carries advanced radars to study the structure of the lunar
crust at shallow depths along its path, and it is outfitted with
spectrometers to detect the elements making up the moon's soil and
rocks, said Pei Zhaoyu, a spokesperson for the Chang'e 3 mission, in a report by Xinhua.
Four navigation and panoramic cameras are mounted on the rover to return high-resolution images from the moon.
The mission also has an optical telescope for astronomical observations from the lunar surface, according to Pei.
China's
lunar program is focused on robotic missions for now, with plans for an
unmanned mission to return rock samples to Earth by 2020. China's
military-run human space program is focused on development of a space
station in Earth orbit around the same timeframe, but scientists have
studied a manned lunar mission in the next decade.
Chang'e 3 will be China's first mission to test the technologies required for future lunar surface exploration.