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/