INSUBCONTINENT EXCLUSIVE:
Image copyrightCNSA/AFPImage caption
The first close up pictures of the far side of the Moon
What will
China's Chang'e-4 mission learn about the far side of the Moon Here are a few things the mission is designed to do.Learn about the Moon's
historyNo space mission has ever explored the far side from the surface
As such, it's the first chance to explore a mysterious region of Earth's natural satellite
The "face" that's never seen from Earth has some key differences to the more familiar "near side"
The far side has a thicker, older crust that is pocked with more craters
There are also very few of the "maria" (dark basaltic "seas" created by lava flows) that are evident on the near side.Chang'e-4 has
basin on the Moon and formed when an asteroid - perhaps 500km across, or more - collided with it billions of years ago
This event was so powerful that it is thought to have ploughed through the Moon's outer crust layer and through into the zone known as the
mantle.One of the mission's objectives is to study any exposed material from the mantle present at the landing site
This would provide insights into the internal structure and history of the Moon.Image copyrightNASAImage caption
The
South Pole-Aitken basin was formed by a giant impact billions of years ago
Indeed, data from orbiting spacecraft show that
the composition of the basin is different from the surrounding lunar highlands
But exposed mantle material on the surface is just one possibility among several to explain this observation.The rover will use its
panoramic camera to identify interesting locations and its Visible and Near-Infrared Imaging Spectrometer (VNIS) to study minerals in the
floor of the crater (as well as of ejecta - rocks thrown out by nearby space impacts).Additionally, the Lunar Penetrating Radar (LPR)
instrument will be able to look into the shallow subsurface of the Moon, down to a depth of about 100m
It could probe the thickness of the lunar regolith - the broken up rocks and dust that make up the surface - and shed light on the structure
of the upper lunar crust.After the huge impact that created the South Pole-Aitken basin, a large amount of melted rock would have filled the
The science team wants to use Chang'e-4 to identify and study variations in its composition.Filling an astronomy gapThe far side of the Moon
has long been regarded as an ideal spot for conducting a particular kind of radio astronomy - in the low-frequency band - because it's
shielded from the radio noise of Earth
There's a frequency band (below about 10MHz) where radio astronomy observations can't be conducted from Earth, because of manmade radio
interference and other, natural factors.Chang'e-4's lander is carrying an instrument called the Low Frequency Spectrometer (LFS) which can
make low frequency radio observations
It will be used in concert with a similar experiment on the Queqiao orbiting satellite.The objectives include making a map of the radio sky
at low frequencies and studying the behaviour of the Sun.Speaking in 2016, Liu Tongjie, from the Chinese space agency (CNSA), said: "Since
the far side of the Moon is shielded from electromagnetic interference from the Earth, it's an ideal place to research the space environment
and solar bursts, and the probe can 'listen' to the deeper reaches of the cosmos."Thus, the mission will fill a gap in astronomical
observation, allowing scientists to study cosmic phenomena in a way that has never been possible from our planet.Radiation on the MoonImage
copyrightScience Photo LibraryImage caption
Understanding the radiation environment will be vital for future human
exploration
Several space agencies want to land humans on the Moon in the not-too-distant future, and might send astronauts
there for longer than we've ever stayed before
So understanding the potential risks from radiation are vital.Earth's thick atmosphere and strong magnetic field provide adequate shielding
against galactic cosmic rays and energetic charged particles travelling from the Sun
But astronauts on the Moon will be outside this protective bubble and exposed to particles travelling through open space at near the speed
of light - with potentially damaging consequences for their health.The Lunar Lander Neutrons and Dosimetry (LND) experiment, supplied by
researchers in Germany, will aim to fill in some gaps in our understanding about the lunar radiation environment.It will provide dosimetry
(measure the ionising radiation dose that could be absorbed by the human body) with a view to future exploration, and contribute to
understanding of particles originating from the Sun.Follow Paul on Twitter.
