ASTEROID
1. Context
Indian Space Research Organisation (ISRO) Chairman S Somanath said last week that “we should be able to go and meet” the asteroid Apophis when it passes by Earth at a distance of 32,000 km in 2029
2. What are asteroids?
Asteroids are small, rocky objects that orbit the Sun, primarily found in the asteroid belt between the orbits of Mars and Jupiter. They are remnants from the early solar system that never coalesced into planets.
Asteroids vary widely in size, from tiny pebbles to objects that are hundreds of kilometers in diameter. The largest known asteroid, Ceres, is about 940 kilometers (about 580 miles) in diameter
Asteroids are composed of various materials, including rock, metal, and sometimes organic compounds. Their composition can provide clues about the early solar system.
They are categorized based on their composition:
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- C-type (carbonaceous): Rich in carbon and the most common type.
- S-type (silicaceous): Made up of silicate minerals and nickel-iron.
- M-type (metallic): Mostly composed of metallic iron and nickel
Source: Indianexpress
3. How are asteroids different from satellites?
| Aspect | Asteroid | Satelite |
| Definition | Asteroids are small, rocky objects that orbit the Sun. They are remnants from the early solar system that did not form into planets | Satellites are natural or artificial objects that orbit around planets, dwarf planets, or other celestial bodies. Natural satellites are commonly known as moons |
| Orbit | Asteroids primarily orbit the Sun, mostly found in the asteroid belt between Mars and Jupiter. Some, known as Near-Earth Asteroids (NEAs), have orbits that bring them close to Earth | Satellites orbit planets or other celestial bodies rather than the Sun. Their orbits are influenced by the gravitational pull of the body they orbit |
| Composition | Asteroids are composed of rock, metal, and sometimes organic compounds. Their composition can vary widely, leading to different types such as C-type (carbonaceous), S-type (silicaceous), and M-type (metallic) | Natural satellites vary in composition depending on their parent planet. They can be rocky (like Earth’s Moon), icy (like Europa, one of Jupiter’s moons), or a mix of rock and ice (like Titan, Saturn’s moon) |
| Size and Shape | Asteroids range in size from small boulders to objects hundreds of kilometers in diameter. They often have irregular shapes due to their small size and insufficient gravity to form spherical shapes | Natural satellites range in size from small moonlets to large bodies like Ganymede, which is larger than the planet Mercury. Many larger moons are spherical due to their sufficient gravitational force, while smaller moons often have irregular shapes |
| Examples | Notable asteroids include Ceres (the largest and classified as a dwarf planet), Vesta, Bennu, and Ryugu. | Notable natural satellites include Earth’s Moon, Jupiter’s moons (e.g., Ganymede, Io, Europa, Callisto), Saturn’s moons (e.g., Titan, Enceladus), and Mars’ moons (Phobos and Deimos) |
| In 2022, the DART spacecraft successfully managed to change the motion of the asteroid Dimorphos by crashing into it. This is the first time that humanity has changed the motion of a celestial object. This is also the first demonstration of the “kinetic impactor” method of asteroid mitigation |
4. What was the objective of the DART mission?
The Double Asteroid Redirection Test (DART) mission, conducted by NASA, aimed to test and demonstrate a method of asteroid deflection by kinetic impact. This mission was the first of its kind, focusing on planetary defense strategies to protect Earth from potential asteroid impacts.
Here are the key objectives and details of the DART mission:
- The primary objective was to test the effectiveness of the kinetic impact technique in altering the trajectory of an asteroid. This involves sending a spacecraft to collide with an asteroid at high speed to change its orbit
- The mission targeted the binary asteroid system Didymos, specifically its moonlet, Dimorphos. Didymos is a near-Earth asteroid, and Dimorphos, which orbits Didymos, was chosen for the impact test
- A critical objective was to measure the change in the orbit of Dimorphos around Didymos resulting from the kinetic impact. This change in orbit would demonstrate the feasibility of deflecting an asteroid to prevent a potential collision with Earth
- Collect data on the impact event, including the resulting crater, the ejecta (material expelled from the asteroid), and the change in the asteroid's momentum. This information is crucial for refining models and planning future asteroid deflection missions
- Showcase the technologies required for an asteroid deflection mission, including navigation, targeting, and impact capabilities. This demonstration helps validate the methods and tools needed for future planetary defense missions
5.Way Forward
The DART mission was part of NASA's larger planetary defense strategy, aimed at developing methods to protect Earth from potential asteroid impacts in the future
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Source: Indianexpress
