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PLANETARY DEFENCE

13th July, 2024

PLANETARY DEFENCE

Source: Space.com

Disclaimer: Copyright infringement not intended.

Context

  • 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.

Details

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.

Country

Agency/Organization

Key Initiatives/Projects

Description

United States

NASA

Planetary Defense Coordination Office (PDCO)

Established in 2016 to manage efforts to detect, track, and characterize NEOs and develop mitigation strategies.

Double Asteroid Redirection Test (DART)

Mission to demonstrate the kinetic impactor technique by crashing into the asteroid Dimorphos to change its orbit.

NEOWISE

A space-based infrared telescope repurposed to detect and characterize NEOs.

OSIRIS-REx

Redirected to observe asteroid Apophis during its 2029 flyby after completing its primary mission to asteroid Bennu.

SETI Institute

Asteroid Terrestrial-impact Last Alert System (ATLAS)

A ground-based system designed to detect incoming asteroids that could impact Earth, providing advance warning.

European Union

European Space Agency (ESA)

Hera Mission

A mission to follow up on NASA's DART impact, studying the effects on the binary asteroid system Didymos and Dimorphos.

Flyeye Telescope

A ground-based telescope in Italy designed to detect and track NEOs with wide-field optics.

NEO Coordination Centre

Central hub for data on NEO observations and risk assessments, facilitating international collaboration.

Russia

Roscosmos

Automated Warning System

A system to monitor and provide warnings about potential asteroid threats.

Observational Programs

Various ground-based telescopes and observatories dedicated to tracking NEOs.

China

CNSA (China National Space Administration)

Planetary Defense Initiative

Announced plans for a planetary defense system including asteroid detection, monitoring, and potential deflection missions.

Ground-based Observatories

Expansion of ground-based infrastructure for NEO detection and tracking.

India

ISRO (Indian Space Research Organisation)

Planetary Defense Workshop

Held workshops and expressed interest in planetary defense, potentially collaborating with other agencies for missions like observing asteroid Apophis in 2029.

Space Situational Awareness & Management (SSAM) Directorate

Plans to include planetary defense within its broader space situational awareness efforts.

Japan

JAXA (Japan Aerospace Exploration Agency)

Hayabusa2

Mission to asteroid Ryugu, collecting samples and returning them to Earth. This mission provided valuable data on asteroid composition and behavior.

Germany

DLR (German Aerospace Center)

Space Situational Awareness Program

Includes efforts to detect and track NEOs, collaborating with international partners.

Italy

Italian Space Agency (ASI)

NEO Surveillance

Collaboration with ESA on projects like Flyeye Telescope and other ground-based observation systems.

United Kingdom

UK Space Agency

NEO Detection Research

Involvement in ESA's Hera mission and support for ground-based telescopes and observatories.

Australia

Space Environment Research Centre (SERC)

Observational Programs

Efforts to detect and track NEOs using ground-based observatories and collaborations with international partners.

Canada

Canadian Space Agency (CSA)

Near-Earth Object Surveillance Satellite (NEOSSat)

A microsatellite dedicated to tracking and monitoring NEOs from space.

Asteroid Day

Held annually on June 30th, Asteroid Day raises global awareness about asteroids and planetary defense. It involves educational programs and expert discussions on the latest research and strategies.

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 .

Physical Characteristics

  • Size and Composition: Apophis is approximately 450 meters wide and is believed to be composed of silicate materials, typical of S-type asteroids. Its size and composition suggest that an impact would have catastrophic effects.
  • Rotation: Apophis has a rotation period of approximately 30.4 hours. Understanding its rotation is crucial for assessing potential future trajectories and impact risks .

Asteroids, comets, meteors, meteorites, and meteoroids

Category

Definition

Location

Composition

Notable Characteristics

Asteroids

Rocky objects orbiting the Sun, primarily found in the asteroid belt between Mars and Jupiter

Mainly in the asteroid belt

Rock, metal

Generally irregular in shape; vary in size from small rocks to large objects

Comets

Icy bodies that release gas and dust, forming a glowing coma and tail when near the Sun

Kuiper Belt, Oort Cloud

Ice, dust, rocky material

Display a visible coma and tail; often highly elliptical orbits

Meteoroids

Small particles from comets or asteroids

Throughout the solar system

Rock, metal

Smaller than asteroids; typically less than a meter in diameter

Meteors

Meteoroids that enter Earth's atmosphere and burn up, creating a streak of light

Earth's atmosphere

Rock, metal

Known as "shooting stars"; visible as bright streaks in the sky

Meteorites

Fragments of meteoroids that survive passage through the atmosphere and reach Earth's surface

Earth's surface

Rock, metal

Can be stony, metallic, or a combination (stony-iron); valuable for scientific study

Sources:

IndianExpress

PRACTICE QUESTION

Q: Consider the following statements regarding planetary defence mechanisms:

  1. Planetary defence involves strategies to protect Earth from potential asteroid impacts.
  2. The Double Asteroid Redirection Test (DART) mission aims to demonstrate the kinetic impactor technique for deflecting asteroids.
  3. Nuclear detonation is a widely accepted method for asteroid deflection due to its precision and minimal environmental impact.

Which of the statements given above is/are correct?

a) 1 and 2 only
b) 1 and 3 only
c) 2 and 3 only
d) 1, 2, and 3

Answer: a)