News NotesNASA / JPL-CALTECHIn the fi rst non-crash landing
on the Moon in the 21st century,
Chang’e 3 touched down success-
fully on the fl at volcanic plain of
Sinus Iridum at 13:11 Universal
Time on December 14th.
Chang’e 3 is the third space-
craft of the China Lunar Explo-
ration Program. Lunar orbiter
Chang’e 1 launched in 2007;
launched in 2010, Chang’e 2 is
traveling through deep space afterleaving lunar orbit and encounter-
ing asteroid 4179 Toutatis in 2012.
The successful landing marks
the fi rst time the Chinese space
program has landed anything on
an extraterrestrial body. China
now joins the select ranks of the
U.S. and former Soviet Union as
the only countries to set mechani-
cal foot on the Moon.
Chang’e 3 consists of a service
module and a landing vehicle.The 1,200-kg (2,600-pound)
lander is equipped with an imag-
ing spectrometer, two panoramic
cameras, and ground-penetrating
radar. It also carries a telescope
to observe the dense torus of ion-
ized gas encircling Earth, called
the plasmasphere.
Within six hours of landing,
mission controllers deployed a
solar-powered, six-wheeled rover
that is one-tenth the lander’sweight and will explore the ter-
rain around the landing site. The
rover is aptly named Yutu, for the
rabbit companion of Chang’e,
a mythological Chinese woman
who takes an immortality pill that
sends her fl oating to the Moon.
Although expected to yield
new insights into lunar science,
Chinese offi cials also hope that
the Chang’e 3 mission will be a
precursor to human exploration
of Earth’s satellite.
■ EMILY POORECuriosity spent many months exploring
outcrops in an expanse inside Gale Crater
dubbed Yellowknife Bay. Mission scientists
soon realized that much of the terrain was
covered in mudstone, silty sediments that
settled onto the bottom of an ancient lake.
What’s now clear, as reported by one
team led by project scientist John Grotz-
inger (Caltech) and a second by David
Vaniman (Planetary Science Institute), is
that the sediments contain an iron- and
sulfur-rich clay called smectite. This clay
formed in water with a neutral pH and lowMARS I A Habitable Past for a Desert Planet?
salinity — just the kind of benign habitat
that primitive life forms called chemolitho-
autotrophs would want. Such microbes
derive their energy from the oxidation of
inorganic compounds and their carbon
from atmospheric carbon dioxide.
A separate analysis by Kenneth Farley
(Caltech) and others used isotopic ratios to
estimate the age of a mudstone slab nick-
named Cumberland. It’s between 3.86 and
4.56 billion years old, confi rming that Gale
formed very early in Martian history.
But Farley’s team also tested for
elemental isotopes produced by the potent
cosmic rays that bombard the Martian
surface. Cumberland’s “exposure age” is
comparatively young, only 50 to 100 mil-
lion years. Apparently the sediments in
Yellowknife Bay spent eons buried under
a protective cover of overlying mate-
rial, which the planet’s incessant winds
stripped away in the recent geologic past.
This means the rover could detect any
organic matter that might be trapped in
these ancient sediments. Not all organ-
ics are biogenic, but planets — especially
geologically dead ones — are inherently
inorganic systems. Douglas Ming (NASA
Johnson Space Center) and colleagues
report that Curiosity continues to detect
simple organics in surface samples, and
they can’t all be contaminants brought
from Earth. They might be indigenous to
Mars or introduced by meteorites.
■ J. KELLY BEATTYThe researchers coordinating NASA’s
Mars Science Laboratory have always
stressed that their beefy Curiosity rover is
not searching for life on the Red Planet.
Rather, it’s designed to fi nd out whether
Mars was ever suitable for life.
After a year of zapping, sniffi ng, and
tasting rocks and sand, the answer is “yes.”
A fl urry of fi ndings in the December 9th
Science (and announced simultaneously at
the American Geophysical Union meeting)
provide the best evidence yet that ancient
Mars was indeed habitable.Curiosity’s Mast Camera recorded this view of sedimentary deposits inside Gale Crater in February- Wind-driven sandblasting appears to be eating away at the sandstone (rust-colored ledge in
the foreground) to expose mudstone below. The sandstone ledge is about 20 cm (8 inches) high.
MISSIONS I China Lands Lunar Rover
NASA / JPL-CALTECH / MSSS12 March 2014 sky & telescopeNN layout.indd 12 12/23/13 11:38 AM