Chang’e 5 Lunar Mission

In News 

• Recently, China’s Chang’e 5 lunar lander found the first-ever on-site evidence of water on the surface of the moon, lending new evidence to the dryness of the satellite.
  • The presence of water had been confirmed by remote observation but the lander has now detected signs of water in rocks and soil.

Recent Findings 

• It revealed that the lunar soil at the landing site contains less than 120 parts-per-million (ppm) water or 120 grams water per ton, and a light, vesicular rock carries 180 ppm, which are much drier than that on Earth.
  • It revealed that the moon had turned drier within a certain period, owing probably to the degassing of its mantle reservoir.

• The humidity of lunar soil: It was the solar wind that contributed to the most humidity of lunar soil as it brought hydrogen that makes up the water.

• Additional 60 ppm water: The additional 60 ppm water in the rock may originate from the lunar interior.
  • Therefore, the rock is estimated to hail from an older, more humid basaltic unit before being ejected onto the landing site to be picked up by the lunar lander.
• Measurement method 
  • It measured water on the spot and retrieved samples weighing 1,731 grams.
  • A device on-board the lunar lander measured the spectral reflectance of the regolith and the rock and detected water on the spot for the first time.
    • The water content can be estimated since the water molecule or hydroxyl absorbs at a frequency of about three micrometres.

• Significance:
  • The findings provide more clues to China’s Chang’e-6 and Chang’e-7 missions. 
    • The investigations of lunar water reserves come into the limelight as the building of manned lunar stations are in the pipeline in the next decades

About Chang’e 5 lunar lander

• It has been named after the Chinese Moon goddess.
• It is a series of lunar probes launched by the China National Space Administration for lunar exploration.
• The first lunar landing by China was made in 2013.
  • Prior to Chang’e 5, the Chang’e-4 probe touched down on the far side of the moon in January 2019.
• It was launched on the Long March-5 Y5 rocket from Wenchang Space Launch Center (China).
• The rocket consists of four parts: an orbiter, a returner, an ascender and a lander.
• The Mission comprises: a robotic arm, a coring drill, a sample chamber and is also equipped with a camera, penetrating radar and a spectrometer.
• Objectives: 
  • To bring back lunar rocks which is the first attempt by any nation to retrieve samples from the moon in four decades.
  • To dig about 2 metres deep into the surface of the Moon and collect 2 KGs of the sample.
    • This will help scientists learn about the moon’s origins, formation and volcanic activity on its surface.
  • To steadily increase their technological capabilities, laying the groundwork for future human landings.

• Why are Lunar Samples important?
  • They can help to unravel some important questions in lunar science and astronomy, including the Moon’s age, the formation of the Moon, the similarities and differences between the Earth, the Moon’s geologic features and the information about the solar system itself.
  • The shape, size, arrangement and composition of individual grains and crystals in a rock can tell scientists about its history, while the radioactive clock can tell the rock’s age.
  • The tiny cracks in rocks can provide information about the radiation history of the Sun in the last 100,000 years.

Early Lunar Sample Collection missions:

• The first samples of rocks from the Moon were collected during the Apollo 11 mission of the US.
• In 1970, the Soviet Union’s Luna 16 probe returned a sample weighing about 101 grams and taken from the Mare Fecunditatis area of the Moon. 
  • In 1976, Luna 24 collected a sample weighing over 170 grams from 2 metres deep into the lunar soil.

Source: TH