IAS Gyan

Daily News Analysis


18th August, 2022 Science and Technology

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  • The Hayabusa-2 probe brought 5.4 grams of rocks and dust from the asteroid Ryugu to Earth in December 2020. In an article published recently in the journal Nature Astronomy scientists from Japan suggest that water and organic materials might have been brought to our planet from the outer edges of the solar system.



  • Hayabusa2 is an asteroid sample-return mission operated by the Japanese state space agency JAXA. It is a successor to the Hayabusa mission, which returned asteroid samples for the first time in June 2010.
  • Hayabusa2 was launched on 3 December 2014 and rendezvoused in space with near-Earth asteroid 162173 Ryugu on 27 June 2018.
  • It surveyed the asteroid for a year and a half and took samples. It left the asteroid in November 2019 and returned the samples to Earth on 5 December 2020 UTC. Its mission has now been extended through at least 2031, when it will rendezvous with the small, rapidly-rotating asteroid 1998 KY26.
  • Hayabusa2 carried multiple science payloads for remote sensing and sampling, and four small rovers to investigate the asteroid surface and analyze the environmental and geological context of the samples collected.

Asteroids and Ryugu

  • Asteroids are rocky objects that orbit the Sun, much smaller than planets. They are also called minor planets. According to NASA, there are 994,383 known asteroids, the remnants from the formation of the solar system over 4.6 billion years ago.
  • Asteroids are divided into three classes. First are those found in the main asteroid belt between Mars and Jupiter, which is estimated to contain somewhere between 1.1-1.9 million asteroids.
  • The second group is that of trojans, which are asteroids that share an orbit with a larger planet. NASA reports the presence of Jupiter, Neptune and Mars trojans. In 2011, they reported an Earth trojan as well.
  • The third classification is Near-Earth Asteroids (NEA), which have orbits that pass close to the Earth. Those that cross the Earth’s orbit are called Earth-crossers. More than 10,000 such asteroids are known, out of which over 1,400 are classified as potentially hazardous asteroids (PHAs).
  • Ryugu is also classified as a PHA and was discovered in 1999 and was given the name by the Minor Planet Center in 2015. It is 300 million kilometres from Earth and it took Hayabusa-2 over 42 months to reach it.