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Key phrase: DART mission, Kinetic Impactor technique, Didymos, Dimorphos asteroid

Why in news:

NASA launched a test mission-DART to alter the path of an asteroid. The Double Asteroid Redirection Test (DART) mission blasted off from Vandenberg Space Force Base in California at 6.21am GMT. Its purpose is to divert the course of an asteroid called Dimorphos.

Analysis:

What is DART?

• DART is a planetary defense-driven test of technologies for preventing an impact of Earth by a hazardous asteroid. DART will be the first demonstration of the kinetic impactor technique to change the motion of an asteroid in space.
• DART is a spacecraft designed to impact an asteroid as a test of technology. DART’s target asteroid is NOT a threat to Earth. This asteroid system is a perfect testing ground to see if intentionally crashing a spacecraft into an asteroid is an effective way to change its course, should an Earth-threatening asteroid be discovered in the future. While no known asteroid larger than 140 meters in size has a significant chance to hit Earth for the next 100 years, only about 40 percent of those asteroids have been found as of October 2021.

The main aim of DART:

The main aim of the Double Asteroid Redirection Test (DART) mission is to test the newly developed technology that would allow a spacecraft to crash into an asteroid and change its course.

DART's target asteroid:

The binary near-Earth asteroid (65803) Didymos is the target for the DART demonstration. While the Didymos primary body is approximately 780 meters across, its secondary body (or “moonlet”) is about 160-meters in size, which is more typical of the size of asteroids that could pose the most likely significant threat to Earth. The Didymos binary is being intensely observed using telescopes on Earth to precisely measure its properties before DART arrives.

Why Dimorphos?

Didymos is a perfect system for the test mission because it is an eclipsing binary which means it has a moonlet that regularly orbits the asteroid and we can see it when it passes in front of the main asteroid. Earth-based telescopes can study this variation in brightness to understand how long it takes Dimorphos to orbit Didymos.

Structure of DART:

• The main structure is a box (1.2 × 1.3 × 1.3 metres). It has two solar arrays and uses hydrazine propellant for maneuvering the spacecraft.

• It also carries about 10 kg of xenon which will be used to demonstrate the agency’s new thrusters called NASA Evolutionary Xenon Thruster–Commercial (NEXT-C) in space. “NEXT has very high fuel efficiency and flexible operations making it ideal for many classes of science missions.

• The spacecraft carries a high-resolution imager called Didymos Reconnaissance and Asteroid Camera for Optical Navigation (DRACO). Images from DRACO will be sent to Earth in real-time and will help study the impact site and surface of Dimorphos.

• DART will also carry a small satellite or CubeSat named LICIACube (Light Italian CubeSat for Imaging of Asteroids). It will be deployed ten days before the impact on Dimorphos. LICIACube is expected to capture images of the impact and the impact crater formed as a result of the collision. It can also capture images of any dust cloud formed during the impact.

Kinetic impactor technique:

The kinetic impactor technique works by changing the speed of a threatening asteroid by a small fraction of its total velocity, but by doing it well before the predicted impact so that this small nudge will add up over time to a big shift of the asteroid’s path away from Earth.

Way forward

The DART mission can hopefully give NASA and other space agencies in the world the nod to go ahead and stop if a giant space rock heads towards us to wipe out life on Earth one day and prevent the doomsday destruction.

Source: Indian Express

Related Prelims Question

Q. Consider the following statements about Double Asteroid Redirection Test (DART) mission:

1. DART is a planetary defense-driven test of technologies for preventing an impact of Earth by a hazardous asteroid.

2. It is a joint venture of NASA and ISRO.

3. It does not carry any satellite on board.

Which of the statements given above are correct?

(a) 1 only

(b) 2 and 3 only

(c) 3 only

(d) 1, 2 and 3

Answer: (a)