PLANETARY DEFENCE
Source: Space.com
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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.
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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. |
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Double Asteroid Redirection Test (DART) |
Mission to demonstrate the kinetic impactor technique by crashing into the asteroid Dimorphos to change its orbit. |
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NEOWISE |
A space-based infrared telescope repurposed to detect and characterize NEOs. |
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|
OSIRIS-REx |
Redirected to observe asteroid Apophis during its 2029 flyby after completing its primary mission to asteroid Bennu. |
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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. |
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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. |
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NEO Coordination Centre |
Central hub for data on NEO observations and risk assessments, facilitating international collaboration. |
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Russia |
Roscosmos |
Automated Warning System |
A system to monitor and provide warnings about potential asteroid threats. |
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Observational Programs |
Various ground-based telescopes and observatories dedicated to tracking NEOs. |
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China |
CNSA (China National Space Administration) |
Planetary Defense Initiative |
Announced plans for a planetary defense system including asteroid detection, monitoring, and potential deflection missions. |
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Ground-based Observatories |
Expansion of ground-based infrastructure for NEO detection and tracking. |
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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. |
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Space Situational Awareness & Management (SSAM) Directorate |
Plans to include planetary defense within its broader space situational awareness efforts. |
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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. |
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Italy |
Italian Space Agency (ASI) |
NEO Surveillance |
Collaboration with ESA on projects like Flyeye Telescope and other ground-based observation systems. |
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United Kingdom |
UK Space Agency |
NEO Detection Research |
Involvement in ESA's Hera mission and support for ground-based telescopes and observatories. |
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Australia |
Space Environment Research Centre (SERC) |
Observational Programs |
Efforts to detect and track NEOs using ground-based observatories and collaborations with international partners. |
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Canada |
Canadian Space Agency (CSA) |
Near-Earth Object Surveillance Satellite (NEOSSat) |
A microsatellite dedicated to tracking and monitoring NEOs from space. |
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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 |
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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 |
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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:
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PRACTICE QUESTION Q: Consider the following statements regarding planetary defence mechanisms:
Which of the statements given above is/are correct? a) 1 and 2 only Answer: a) |
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