On Monday, NASA’s Double Asteroid Redirection Test (DART) will see if humanity is able to defend against asteroids or comets that are on a high-speed trajectory towards the Earth.
The 20-yard-long spacecraft will be deliberately crashed into Dimorphos, an asteroid that is about twice as high as the Empire State Building and 530-feet-wide.
Dimorphos is circling a larger asteroid called Didymos.
The 1100-pound DART craft launched on November 24 last year and it is due to reach its destination, Didymos, on Monday, September 26, 2022.
Once it arrives, it will purposefully crash into Didymos’s moon, the 530-foot-wide asteroid Dimorphos, in an attempt to divert the smaller rock’s orbit around its parent asteroid.
Neither Didymos nor Dimorphos presents any threat to Earth, being seven million miles away, but mission scientist Andy Rivkin at Johns Hopkins University in Maryland and his team hope the asteroid system can act as a test-bed for dealing with potentially deadly space rocks.
“This is an experiment at the kinds of scales that we want to use, or that we might use if we ever need to deflect an asteroid for real,” said Rivkin.
The researchers will deem the mission a success if DART’s impact, which will be at around 21,650 feet per second, changes the length of Dimorphos’s orbit by at least 73 seconds, give or take 10 percent – but they think that the real diversion could be closer to around 10 minutes.
Although DART has a camera onboard, the spacecraft will be destroyed on impact, so won’t be able to see the outcome. Instead, the team will rely on LICIACube – a sister spacecraft from the Italian Space Agency that separated from DART on 11 September – to take detailed observations.
DART is the first-ever mission dedicated to investigating and demonstrating one method of asteroid deflection by changing an asteroid’s motion in space through kinetic impact.
This method will have DART deliberately collide with a target asteroid—which poses no threat to Earth— in order to change its speed and path. DART’s target is the binary, near-Earth asteroid system Didymos, composed of the roughly 2,560-foot-diameter “Didymos” and the smaller, approximately 530-foot-size “Dimorphos,” which orbits its larger neighbor.
DART will strike Dimorphos to change its orbit within the binary system, and the DART Investigation Team will compare the results of DART’s kinetic impact with Dimorphos to highly detailed computer simulations of kinetic impacts on asteroids.
Doing so will evaluate the effectiveness of this mitigation approach and assess how best to apply it to future planetary defense scenarios, as well as how accurate the computer simulations are and how well they reflect the behavior of a real asteroid.