Chandrayaan-3 to be launched on July 12: Chandrayaan-2 and why it partially failed

Chandrayaan-3 to be launched on July 12: Chandrayaan-2 and why it partially failed

Context- Almost four years after its first unsuccessful attempt to make a spacecraft land on the Moon, Isro will launch its third moon mission, Chandrayaan-3 (Ch-3), on July 12, with the primary objective of executing a precise landing on the celestial body. In 2019, the lander and rover of the Chandrayaan-2 mission malfunctioned in the final moments and crash-landed, getting destroyed in the process.

(Credits- Indian Express)

Launched on July 22, 2019, the Chandrayaan-2 mission’s Vikram lunar lander crashed on the Moon during the early hours of September 6. Its debris was later found by NASA around three months later. Despite the setback, the mission wasn’t a complete failure as its Orbiter part kept on working normally and gathered a wealth of new information that added to our knowledge about the Moon and its environment.

What was the Chandrayaan-2 mission?

  • Although the most talked about objective of the Chandrayaan-2 was to demonstrate the ability to soft-land a lander and rover on the unexplored south pole of the Moon, it also had other goals.
  • The mission was “designed to expand the lunar scientific knowledge through a detailed study of topography, seismography, mineral identification and distribution, surface chemical composition, thermo-physical characteristics of topsoil and composition of the tenuous lunar atmosphere, leading to a new understanding of the origin and evolution of the Moon
  • In 2021, the space agency revealed that the mission’s Orbiter had produced a handsome amount of data about the Moon. This helped in building upon existing knowledge of the celestial body in terms of its surface, sub-surface and exosphere.
  • For instance, a key outcome from Chandrayaan-2 was the exploration of the permanently shadowed regions as well as craters and boulders underneath the regolith, the loose deposit comprising the top surface extending up to 3-4m in depth.

What went wrong with the Chandrayaan-2’s Vikram lander?

  • The landing of Vikram was targeted for a plane about 600 km from the south pole of the Moon. However, ISRO lost contact with their lander shortly before the scheduled touchdown on September 7.
  • When contact was lost, it was travelling at 50 to 60 metres per second (180 to 200 km per hour). It was decelerating, but not fast enough to slow down to a speed of 2 metres/second (7.2 km/hr) that was required for a safe landing.
  • Vikram was designed to absorb the shock of an impact even at 5 metres/second (18 km/hr). At the rate it was decelerating, it could not even have attained a speed of 5 metres/second before touchdown. It hit the Moon at a far greater speed, damaging itself and the instruments on board.

What was missed because of the crash landing?

  • The most obvious miss was the opportunity to demonstrate the technology to make a soft landing in outer space. Isro scientists at the time said the accident was caused by a relatively small error that had been identified and corrected.
  • The soon-to-be-launched Chandrayaan-3 mission will demonstrate this technology, hopefully, without any glitches.

Conclusion- The lander Vikram and rover Pragyaan were carrying instruments to carry out observations on the surface. These were supposed to pick up additional information about the terrain, composition and mineralogy. With the support of the Orbiter, Vikram and Pragyaan would have provided two diverse sets of data that could have helped prepare a more composite picture of the Moon.

Syllabus- GS-3; Science and Tech

Source- Indian Express