Prelims cum Mains Science & Tech

Why China Moon landing is significant?

The News

  • China’s Chang’e-4 moon mission, the 1st ever probe to land on far side of the moon, has transmitted images of the far side of the moon.


About Chang’e-4

  • Recently, China launched the Chang’e-4 lunar probe mission, the first ever probe to land on and explore the far side of the moon.
  • The Chang’e-4 probe involved a relay satelliteQueqiao and lander-rover satellite.
  • Chang’e-4’s lander-rover combination is set to explore both above and below the lunar surface.
  • Chang’e-4 landed its rover in the Aitken Basin’s Von Karman crater in the South Pole region which is the largest crater in our solar system.
  • Chang’e-4 relay satellite, Queqiao is used to communicate between the rover on the far side of the lunar surface and earth.
  • Chang’e-4 will also conduct the first radio astronomy experiments from the far side of the Moon.

Relay Satellite Queqiao

  • All previous Moon landings, manned and unmanned, have been on the near side.
  • This has been primarily because the Moon would have blocked radio communication between its far side and Earth.
  • The “relay satellite”, called Queqaio has solved this problem.
  • A major challenge for such a mission is communicating with the robotic lander on the far side.
  • This is because the far side of the moon always points away from earth and is not in “line of sight” for transmission of signals.
  • Thus, China launched a relay satellite called Queqiao in May 2018.
  • The Queqiao relay satellite in the moon’s orbit can relay data and commands between the lander and earth.


  • This will be the first ever mission to the unchartered territory of far side of the moon.
  • Unlike the near side of the moon, the far side is mountainous and rugged.
  • The moon’s far side has a different composition and thus the probe will help characterise the geology and the composition of rock and soil in the far side of the moon.

Why do we see only one side of the moon?

  • We always see the same side of the moon as a result of the Moon’s synchronous rotation.
  • Earth’s gravitational pull has brought the Moon’s spin into sync with its orbit.
  • Thus it takes precisely the same amount of time for the Moon to rotate on its axis as it does to complete one orbit around the Earth (exactly 28 days).

Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: