ISRO’s Venture into Planetary Defence

In an international workshop held in Bengaluru to mark the Asteroid Day 2024, ISRO (Indian Space Research Organization) Chairman expressed his desire for India to participate in a planetary Defence Mission in space ahead of the asteroid Apophis close shave with Earth on April 13, 2029 at a distance of 32,000 km.

• Asteroid Day: The day is observed every year by the space community on June 30 on account of a huge air blast from an asteroid flattening 2,200 sq km of forest in Siberia, Russia, on June 30, 1908.

About Apophis

• Discovered: Asteroid Apophis was discovered back in 2004 when scientists estimated a  2.7% chance of the asteroid colliding  with Earth (the highest probability of any large asteroid hitting Earth in the recent past) 
• Size: Apophis measures about 450 m at its widest and with a 200-metre diameter is expected to be peanut-shaped, just like most asteroids of this size.
• Sphere: Its sphere is of 360 days, which is almost one Earth year, and as a result, it can be seen often in the Earth’s vicinity.
• Probability of Collision with Earth: 
• • The object’s coming and impacting the Earth has a probability of  more than one in 100, which is termed as high risk and  could cause large-scale damage.
• Encounter with Earth: The asteroid will come the closest to Earth in 2029, when it will fly at a distance of 32,000 km close enough to be visible to the naked eye
  • 2036: The asteroid is assumed to come back in 2036 again but at a further distance. It is feared that any change in gravity will have a larger chance of having an  impact on Earth in 2036.
• Mission to Apophis: NASA has already redirected one of its spacecraft ( which studied the asteroid Bennu)  to track Apophis. This spacecraft will go within a distance of 4,000 km of Apophis in April 2029, and then trail the asteroid for 18 months, collecting data and analyzing its surface.

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Asteroids and their Threat

• About: Asteroids are sometimes also called minor planets, are rocky, airless remnants left over from the early formation of our solar system about 4.6 billion years ago.
  • The current known asteroid count is 1,379,767
• Orbits: Most asteroids can be found orbiting the Sun between Mars and Jupiter within the main asteroid belt and objects in the Kuiper Belt (a doughnut-shaped region of icy bodies extending far beyond the orbit of Neptune)
• Size Profile: Asteroids range in size from Vesta being the largest at about 329 miles (530 kilometers) in diameter to other objects measuring less than 33 feet (10 meters) across.
• Mass: The total mass of all the asteroids combined is less than that of Earth’s Moon.
• Threat to Earth: 
  • Thousands of asteroids enter the Earth’s atmosphere every single day in the form of Meteors and Meteorites but they are not large enough to cause much damage.
  • Cause Mass Extinction: Asteroids are hypothesized to have caused the extinction of dinosaurs
  • Chelyabinsk Meteor Explosion: In 2013, a 20-metre wide asteroid exploded about 30 km above a Russian town, releasing energy equivalent to 26 to 33 times released by the atom bomb that detonated over Hiroshima.
    • As per the Russian Ministry of Health, while most of this energy was absorbed by the atmosphere, shock waves travelled to the ground, flattened trees, damaged buildings, and injured 1,491 people.
• Need for a Planetary Defence: 
  • Threat from an Undetected Asteroid: The 2013 Russian asteroid was detected only after it entered the atmosphere as  it came from the direction of the Sun, and was hidden by its glare which prompted the scientists to embark on a Planetary Defence mission.
  • Track and Neutralise: Although scientists have knowledge about at least 1.3 million asteroids, but there could be more surprises in store thus,  A planetary defense programme is a must to track and neutralize these threats.

ISRO’s plans for Apophis

• Joint  Apophis Asteroid Mission: ISRO is looking to collaborate in any capacity to study the asteroid Apophis which could involve putting an instrument on the JAXA (Japan Aerospace Exploration Agency), ESA (European Space Agency), and NASA (National Aeronautics and Space Administration) Joint Apophis asteroid mission.
• Aim: ISRO’s main purpose is to participate and learn and spread their knowledge base  in whatever capacity by  providing support in some or any manner to the international missions.
• Future Scope: ISRO aims to position India to handle an asteroid mission, land on an asteroid, and possibly carry out a planetary defence action to protect Earth as a leading space fearing nation.
• Learnings from NASA’s Double Asteroid Redirection Test (DART): The mission showed a spacecraft’s kinetic impact successfully altering the orbit of the asteroid Dimorphos, marking the first full-scale demonstration of asteroid deflection technology and humanity’s first time purposely changing the motion of a celestial object 
  • Follow up Mission: The European Space Agency’s Hera mission will launch in 2024 to visit asteroid Dimorphos and survey the aftermath of the DART impact.
• Upcoming NASA mission: NASA’s upcoming NEO Surveyor mission will help in this regard, pinpointing 90% of near-Earth objects with diameters of at least 140 meters (460 feet) within 10 years.

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