Double Asteroid Redirection Test (DART) Mission: NASA

Context

• NASA will launch the agency’s first planetary defence test mission named the Double Asteroid Redirection Test (DART) on November 24, 2021.

About the DART Mission 

• It is a planetary defence-driven test of technologies for preventing an impact on Earth by a hazardous asteroid. 
• The spacecraft will be launched on a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California.
• Objectives: DART is the first technology demonstration of the kinetic impactor technique that could be used to mitigate the threat of an asteroid hitting Earth. 
  • The kinetic impactor mitigation technique is the impulsive deflection of the asteroid through the sudden addition of momentum. In simpler terms, DART is being sent to collide with an asteroid to change its orbital period.
• Configuration 
  • Weight : A considerably low-cost spacecraft DART weighs about 610 KG at the time of its launch and will shed a little of its weight during its flight and weigh about 550 KG during the impact. 
  • Structure: The main structure is a box (1.2 × 1.3 × 1.3 metres). It has two solar arrays and uses hydrazine propellant for manoeuvring the spacecraft.
  • The spacecraft has been appended with a high-resolution imager called Didymos Reconnaissance and Asteroid Camera for Optical Navigation (DRACO) which will give precise images and information to the scientists to study the impact of the collision on the trajectory of the asteroid.
  • DART will also carry a small satellite or CubeSat named LICIACube (Light Italian CubeSat for Imaging of Asteroids).

Image Courtesy : NASA

[Two different views of the DART spacecraft. The DRACO (Didymos Reconnaissance & Asteroid Camera for OpNav) imaging instrument is based on the LORRI high-resolution imager from New Horizons. The left view also shows the Radial Line Slot Array (RLSA) antenna with the ROSAs (Roll-Out Solar Arrays) rolled up. The view on the right shows a clearer view of the NEXT-C ion engine.]

Targeted asteroid by the DART mission

• It will target Dimorphos, the much smaller “moonlet” of a binary (two-body) asteroid system .
• Dimorphos orbits a larger asteroid named Didymos (Greek for “twin”) which has a diameter of 780 metres. 

• 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 it can be seen 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.

DART  Importance to planetary defence

• NASA established the Planetary Defense Coordination Office to manage its ongoing mission of planetary defence. 
  • The PDCO’s goals are to provide early detection of potentially hazardous objects, track and characterize the objects, study strategies and technologies for mitigating possible impacts, and play a leading role in U.S. government response planning for an actual impact. 
  • DART is the first planetary defence test mission for PDCO.

Source: FE