China to launch Chang’e-4 rover, lander to moon’s far side in December

A photo of Earth and the
far side of the moon.

Chinese National Space
Administration/Xinhuanet

• China said on Wednesday that it
  plans to launch two robots to the moon in December.
• The new mission, called Chang’e-4, aims to set a lunar
  rover and lander on the far side of the moon.
• The robots will study the geology and chemistry of the
  moon’s most ancient and mysterious rocks.
• Another goal of the mission is to see whether the
  region is quiet enough (from human activity) to build a
  sensitive deep-space radio telescope.
• A bonus experiment on Chang’e-4 will try to grow plants
  and worms on the moon.

China’s space agency this week shared new details about its
upcoming Chang’e-4 mission, which aims to launch two robots to
the far side of the moon.

The new mission, named after the mythical moon goddess Chang’e,
is the fourth in an ongoing lunar exploration program. China
ultimately hopes its technological progress will lead to a crewed
lunar landing — the first since NASA’s Apollo program
ended in 1972 — and perhaps domination of space around the moon.

Chinese officials said during a briefing on Wednesday that
Chang’e-4 will rocket toward the moon in December. CCTV, a
state-supervised media outlet, shared online video of the announcement event.

The new mission “will be the first to realize a soft landing on
and inspection of” the far side of the moon, an official said on
Wednesday at China’s National Defense Science and Technology
Bureau in Beijing.

The Yutu or
“Jade Rabbit” rover, part of China’s Chang’e-3 mission, moving
around the lunar surface in December 2013.
China National Space Administration/Chinese Academy of
Sciences

Chang’e-4 is made from backup hardware for Chang’e-3, a nearly
identical mission that launched the Yutu or “Jade
Rabbit” rover along with a stationary probe to the moon’s
near side in 2013. Given Chang’e-3’s success, officials said at the time that the
backup hardware would be retrofitted into a new Chang’e-4
mission.

The plan includes studying some of the moon’s most ancient rocks
— which could help scientists understand the moon’s
extremely violent history — as well as scouting for a
location to build an unprecedented telescope to study the
universe, according to Air and Space magazine.

Chang’e-4 will also test some hardware that China plans to use
for Chang’e-5: a mission designed to collect about 4.4 lbs of
dust and rocks from a northwest part of the moon and
bring those samples back to Earth.

How China will talk to a robot on the far side of the moon

An
illustration of China’s Queqiao relay satellite near the
moon.
CNSA/CAS

The moon is very good at blocking light and radio transmissions
from Earth to its far side. (A lunar
“dark side” is something of a misnomer, since the moon
rotates about once a month.)

When Apollo astronauts orbited the moon, they temporarily (and
expectedly) lost contact with mission control in Houston each
time they passed behind the 2,159-mile-wide ball of rock.

But China is already poised to get around this problem —
literally — since it successfully launched
a precursor mission called Queqiao in May. Queqiao is a
telecommunications satellite now parked in a gravity-neutral spot
in space, called a Lagrange point, that overlooks
the far side of the moon.

“The name Queqiao means ‘magpie bridge’ in Chinese and comes from
a Chinese folk tale, a love story about a flock of magpies that
form a bridge crossing the Milky Way once a year to reunite
lovers known as the Cowherd and the Weaver Girl, as well as their
children” according to a blog post by Luyuan Xu at
the Planetary Society.

Queqiao will act as a “bridge” between Earth and the Chang’e-4
mission after its robots land, helping to send data home and
receive commands from China National Space Administration mission
control.

Where Chang’e-4 will land and explore

A
view of the moon’s Von Kármán crater.

James
Stuby/NASA (CC0 1.0)

The landing site for Chang’e-4 is slated to be the moon’s Von
Kármán crater. The area is near the south pole, where some
craters hide
water ice in permanent shadows — ideal spots to build
permanent human outposts.

The Von Kármán crater also exists within a huge and ancient
feature called the South Pole-Aitken Basin, which was the site of
a cataclysmic impact about 3.9 billion years ago that left behind
a 1,550-mile-wide crater.

That collision is thought to have punched through the moon’s
crust, spewing some of its mantle onto the surface. If pieces of
mantle are indeed there, and Chang’e-4 can sample and study them,
scientists would get an unprecedented view into the moon’s
internal structure and origins.

Chang’e-4 may also deploy an experiment that would take images of
the sky in low-frequency radio waves. That is practically
impossible on Earth, given how noisy humans are with our
electronics. But these frequencies are essential to understanding
the universe’s and our own origins.

“We need these signals to learn whether and how the universe
inflated rapidly in the first trillionth of a trillionth of a
trillionth of a second after the Big Bang,” Joseph Silk, an
astronomer at Johns Hopkins University, wrote in Nature earlier this year.

Lunar silkworms, potatoes, and mustard

Silkworms
may be the next animal to visit the moon.
Nguyen Huy Kham/Reuters

China designed its solar-powered moon rover to last about three
months and its lander to function for about a year.

In addition to the rock-sampling and radio-astronomy experiments,
the mission will carry a miniature ecosystem of life on Earth.

The lander will hold a seven-inch-long aluminum container packed
with potato seeds, Arabidopsis (mustard) seeds, and silkworm
eggs, according to People’s Daily, a state-supervised
media outlet in China.

Zhang Yuanxun, chief designer of the aluminum container,
explained the goal for these seeds and worms in the Chongqing
Morning Post, according to People’s Daily.

“The eggs will hatch into silkworms, which can produce carbon
dioxide, while the potatoes and seeds emit oxygen through
photosynthesis,” Yuanxun said. “Together, they can establish a
simple ecosystem on the moon.”

Na Li contributed Mandarin Chinese translation assistance to
this story.