Monday, September 13, 2021

Nasa will intentionally hit this asteroid to deflect it from 11 million km away

The intercept is scheduled for late September 2022, when the Didymos system is within 11 million kilometres of Earth, enabling observations by ground-based telescopes.

India Today Web Desk 
New Delhi
September 13, 2021


A graphical representation of DART heading on a collision course towards 'Dimorphos'
. (Photo: Nasa)

Remember the Bruce Willis starred Armageddon, where a group of rag-tag amateur astronauts launched on a mission to deflect an asteroid headed towards Earth? Nasa is now in the final stages of attempting a similar mission, but not with astronauts. The American space agency will begin the countdown for its Double Asteroid Redirection Test (DART) mission as the launch window begins in November.

The DART mission will target an asteroid as engineers and astronomers aim to create a defence system able to deflect potential asteroids headed towards Earth in future. The target asteroid for the mission is Didymos, which will act as the testbed for planetary defence-driven technologies aimed at preventing an impact by a hazardous asteroid.

"The DART mission is Nasa’s first planetary defence test mission and will impact an asteroid to demonstrate a technique that could be used in the future to protect Earth from a potential impact. #CountdownToLaunch on November 24!" Nasa tweeted.

WHAT IS THE DART MISSION?


Dubbed as Double Asteroid Redirection Test mission, DART is managed under the Solar System Exploration Program by Nasa, which will achieve the kinetic impact deflection by deliberately crashing itself into the moonlet (asteroid's moon) at a speed of approximately 6.6 kilometres per second.



DART will launch aboard a SpaceX Falcon 9 rocket. (Photo: Nasa)

The spacecraft will carry a suite of onboard cameras, sophisticated autonomous navigation software to track the developments. Engineers aim to change the speed of the moonlet in its orbit around the main body by a fraction of one per cent due to the collision. "This will change the orbital period of the moonlet by several minutes - enough to be observed and measured using telescopes on Earth," Nasa said.

DART will launch aboard a SpaceX Falcon 9 rocket from Vandenberg Air Force Base, California and will arrive at the target asteroid after journeying through space for a year. The spacecraft will be powered by Roll Out Solar Arrays (ROSA) that will fuel its electric propulsion system.

The intercept is scheduled for late September 2022, when the Didymos system is within 11 million kilometres of Earth, enabling observations by ground-based telescopes and planetary radars. “DART is the first step in testing methods for hazardous asteroid deflection. Potentially hazardous asteroids are a global concern, and we are excited to be working with our Italian and European colleagues to collect the most accurate data possible from this kinetic impact deflection demonstration," said Andrea Riley, DART program executive in a statement earlier.

A MOON-BASED ASTEROID

The Near-Earth Asteroid, which is the target for DART, was discovered nearly two decades ago and scientists found it to have a moon and the binary system was given the name “Didymos", which translates to twins in Greek. The moon system was identified in 2003 when astronomer Petr Pravec, at the Ondejov Observatory in Czechia, was tracking the brightness of a still-unnamed asteroid when he recognised a pattern consistent with a small moon.

The DART Mission will intercept with the moon of the asteroid and crash on the surface. (Graphic: Nasa)

According to Nasa, the near-Earth asteroid was originally discovered in 1996 by Joe Montani of the Spacewatch Project at the University of Arizona, but its orbit was needed to be confirmed before it could be named. After confirmation of the Moon, Nasa chose it to be the target of its impact mission and named the Moon 'Dimorphos'.

Dimorphos, 525 feet in diameter and orbit around the larger main body Didymos, which measures 780 meters and because of its proximity to Earth during 2022, astronomers will be able to compare observations from Earth-based telescopes before and after DART’s kinetic impact to determine how much the orbital period of Dimorphos changed.

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