[meteorite-list] China's Next Moon Mission Is Carrying A Rover (Chang'e 3)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 31 Oct 2013 14:39:12 -0700 (PDT)
Message-ID: <201310312139.r9VLdCn2021141_at_zagami.jpl.nasa.gov>


China's Next Moon Mission Targets 'Bay of Rainbows'
by Leonard David
October 31, 2013

China is making major headway in its mission to land a rover on the moon
- a big step forward in the nation's ambitious lunar exploration plans.

At China's Xichang Satellite Launch Center, the moon-bound Chang'e 3 spacecraft
is undergoing its final tests ahead of a planned launch in early December.
Meanwhile, a Long March 3B carrier rocket, reportedly modified with new
technologies and improved reliability, is set to reach the launch center
via train from Beijing on Friday (Nov. 1).

The touchdown target for the Chang'e 3 mission - a lander and a lunar
rover - is thought to be Sinus Iridum, known as the Bay of Rainbows, a
plain of basaltic lava on the moon, according to reports by China media
outlets. An earlier Chinese lunar orbiter, Chang'e 2, eyed the moon-landing
zone in 2010, showing the site's flat topography and other interesting

As for the rover's name, that is to be decided next month, based on nearly
190,000 entries on two China-based websites. According to the Beijing
Times, "Yutu" ("jade hare" in Chinese) leads the list, while "Tansuo"
("explore") and "Lanyue" ("catch moon"), are the second and third choices,

Launch day

China space watcher Bob Christy of the informative website Zarya.info
told SPACE.com that his best estimate for a China lunar launch is Dec.
1. "It could be a day or so later, but is unlikely to be earlier," he

Christy has taken a look at the launch windows.

"For Dec. 1, the optimum launch time is around 14:00 to 15:00 UTC (9:00
a.m. to 10:00 a.m. EST)," he said. "It allows Chang'e to approach the
moon from the north to give a better view of the transfer orbit from China
than would the alternative - around 22:00 UTC (5:00 p.m. EST) for an approach
from the south."

Sunrise over Sinus Iridum commences Dec. 14, Christy added, so landing
will probably be a day or so later to ensure enough light.

"I have a Chinese document that says Chang'e will spend about 10 days
in orbit before landing. Transit time is likely to be 4.6 days - so it
points to Dec. 1 for launch," he said.

As for why China chose Sinus Iridum for the landing site, David Kring,
senior staff scientist at the Lunar and Planetary Institute in Houston,
has some ideas.

In an informal briefing document provided to SPACE.com, Kring showed the
scientific advantages of selecting that region. But he also said that
other factors may also have affected the landing site choice.

For example, China might be factoring in thoughts of returning lunar samples
back to China in the future. Relatively little oomph is needed to rocket
samples back to Earth from the Sinus Iridum region, Kring told SPACE.com

Sinus Iridum is an impact crater, measuring roughly 146 miles (235 kilometers)
across, that was later flooded by basaltic lavas. It is located along
the northwestern edge of the Imbrium basin.

In 1970, the then-Soviet Union's Luna 17 spacecraft landed nearby, dispatching
the Lunokhod 1 moon rover, Kring said.

Rover tools

According to Kring's informal report, which draws from various Chinese
sources, the solar-powered Chang'e 3 rover carries nearly 45 lbs. (20
kilograms) of payload and has a 6-mile (10 km) range after departing the

The six-wheeled robot sports navigation and panoramic cameras. The lower
front portion of the rover carries hazard-avoidance cameras. The rover
will hibernate at night and might survive three lunar nights (three Earth

The rover totes a robotic arm with an Alpha-Proton X-ray Spectrometer,
or APXS.

That APXS tool could, among other duties, study recent impact crater material
that's been tossed out and about, revealing the material below the moon's
surface; look at ejected debris in crater rays and/or in secondary craters;
and help researchers develop a better model for impact cratering processes,
Kring said.

The Chinese rover also appears to be outfitted with a ground-penetrating
radar instrument. If so, that device can test models for regolith thickness,
including rock abundances inferred from orbiting radar experiments, like
the Diviner lunar radiometer experiment on NASA's Lunar Reconnaissance

Also, China's rover could demonstrate the utility of ground-penetrating
radar to advance future exploration of the moon, Kring said.

In Kring's review, the Sinus Iridum mare basalt has modest titanium-ore
content, except near its southeastern margin, where it has very high titanium-ore

Wait-and-see observations

One interesting side story involves NASA's Lunar Atmosphere and Dust Environment
Explorer (LADEE), which recently entered orbit around the moon.

Whether the LADEE spacecraft could detect certain activities of China's
Chang'e 3 mission is worth contemplating, according to SPACE.com contacts
familiar with LADEE operations.

Also in a wait-and-see mode regarding how China's lander/rover operations
will perform is Arizona State University's Mark Robinson, the principal
investigator for LRO's Lunar Reconnaissance Orbiter Camera, or LROC.

"If Chang'e 3 is successful, everyone is pointing to a north Sinus Iridum
landing spot," Robinson told SPACE.com. "I keep seeing east central Sinus
Iridium near Laplace A [crater] as the target - nothing official."

Because that rumor has been floating about for more than a year, the LROC
imaging team has made sure the camera has gotten the best possible coverage
of the prospective landing locale, Robinson said. Before-and-after imaging
is possible, he added, "and it will be fun to watch the rover move away
from the lander, perhaps heading to Laplace A, which is a very spectacular
Received on Thu 31 Oct 2013 05:39:12 PM PDT

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