PLANETARY DEFENCE – SCIENCE & TECHNOLOGY

News: The Indian Space Research Organisation (ISRO) is planning to develop capabilities in planetary defense, an area that involves detecting, tracking, and potentially mitigating threats from near-Earth objects (NEOs) like asteroids.

  • This initiative aligns with global efforts to safeguard Earth from celestial impacts that could have catastrophic consequences.

What’s in the news?

Planetary Defense

  • Planetary defense refers to the methods and strategies developed to detect, track, and mitigate the potential threat posed by near-Earth objects (NEOs) such as asteroids and comets that could impact Earth.
  • The primary goal is to prevent or minimize the damage that an impact could cause to life, property, and the environment.

Detection and Tracking of NEOs

  • Ground-Based Observatories: Various observatories around the world are dedicated to monitoring NEOs. The Pan-STARRS and Catalina Sky Survey are among the most notable for their contributions to discovering new asteroids.
  • Space-Based Observatories: NASA’s NEOWISE mission uses a repurposed space telescope to detect and characterize NEOs in infrared wavelengths. Future missions, such as the NEOMIR mission, aim to identify asteroids hidden in the Sun's glare​.

Mitigation Strategies

  • Kinetic Impact: This involves sending a spacecraft to collide with an asteroid to change its trajectory. NASA's Double Asteroid Redirection Test (DART) mission successfully demonstrated this technique by impacting the asteroid Dimorphos in 2022​​.
  • Nuclear Deflection: Another proposed method involves using a nuclear explosion near the asteroid to alter its course. This is considered a last-resort measure due to the complexities and risks involved.
  • Gravity Tractor: This concept involves a spacecraft hovering near an asteroid, using its gravitational pull to slowly alter the asteroid's trajectory over time.

Asteroid Apophis

  • Asteroid Apophis, formally designated 99942 Apophis, is a near-Earth asteroid that gained notoriety due to initial predictions of a potential collision with Earth.
  • Discovered on June 19, 2004, by astronomers Roy A. Tucker, David J. Tholen, and Fabrizio Bernardi at the Kitt Peak National Observatory, Apophis measures approximately 450 meters in diameter.
  • When first observed, Apophis was calculated to have a 2.7% chance of impacting Earth during its close approach on April 13, 2029.
  • This probability was the highest ever for a large asteroid and caused significant concern among scientists and the public.
  • Updated Risk AssessmentsSubsequent observations and refined calculations have eliminated the possibility of an impact in 2029, 2036, and 2068.
  • Apophis will make a very close approach to Earth on April 13, 2029, passing at a distance of about 32,000 kilometers (19,800 miles), close enough to be visible to the naked eye and within the range of some geostationary satellites.
  • Source: https://indianexpress.com/article/explained/explained-sci-tech/why-isro-wants-to-venture-into-planetary-defence-9447875/