ISRO’s plans to venture into planetary defense.

Sub : Science and tech

Sec: Space

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.

What is Apophis?

99942 Apophis is a near-Earth asteroid and a potentially hazardous object with a diameter of 450 meters at its widest, that caused a brief period of concern in December 2004 when initial observations indicated a probability up to7% that it would hit Earth on April 13, 2029.
Some scientists compared the potential impact to the event that wiped out dinosaurs and most other extant life some 66 million years ago.

What are the possible incoming threats from space?

Earth’s gravity attracts more than a hundred tons (more than 90 metric tons) of small objects and dust from space daily, according to NASA.
Most of this material burns up in the atmosphere without any effect on the planet.
Asteroids of 1 kilometer [0.62 miles] in size or larger have the potential of causing a global disaster if they were to hit the Earth.
While no known comet represents an impact threat for the foreseeable future, comet impacts are possible, albeit extremely rare.

What factors affect whether an object is considered a threat to Earth?

The two main factors are the object’s orbit and its size.
If the trajectory of the object has no chance of intersecting Earth, then it’s not a threat and we need to consider its size.
Small impactors of a few meters in size or less will disintegrate in the atmosphere and cause no damage to the ground.
Objects of tens of meters in size could cause localized damage, 100 meters or more regional scale damage, and 1 km or more global damage.

What is a Planetary Defence System?

Planetary defense is the effort to monitor and protect Earth from asteroids, comets and other objects in space.
In 2022, NASA demonstrated technology that has long been a science fiction staple.
A spacecraft launched in the previous year crashed into an asteroid named Dimorphos, and changed both its shape and its trajectory.
Dimorphous did not pose a threat to Earth, and was circling the Sun some 11 million km away from our planet. But this showed the beginning of a planetary defense programme.
NASA has already redirected one of its spacecraft, one that previously studied the asteroid Bennu, to track Apophis.