NASA has launched many spacecraft into the solar systems, but a new mission that launches in November will attempt to do something unique: to crash into an asteroid and speed up its orbit.
NASA's first venture into active planetary defense is the Double Asteroid Redirection Test, (DART) mission. The mission of planetary defense is to find large asteroids that may collide with Earth, assess the risk they pose, and if necessary, to prevent such calamity. DART will test one method for this last step. It will ram into the smaller moons of asteroid while people watch to see how the moon's orbital period shrinks.
"If an asteroid was a threat, you'd want this technique to be done many years in advance, decades ahead," Nancy Chabot (planetary scientist, DART coordination lead at Johns Hopkins Applied Physics Laboratory, Maryland) said during a prelaunch press conference on Thursday, November 4. You could give the asteroid a little push, which would make a huge difference in its future location, so the Earth and the asteroid wouldn't be on collision course.
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Consider the fate of dinosaurs to understand why scientists are concerned about asteroids. Specialists in planetary defense are trying avoid this kind of impact, which wiped out most dinosaurs around 66 million years back.
There are two phases to planetary defense. First, you need to search the skies for space rocks. Then you need to track asteroids close enough so scientists can create trajectories and compare them with Earth's orbit. NASA statistics show that NASA has identified over 27,000 near-Earth asteroids. Nearly 10,000 of these are larger than 460ft (140m) in size, which is the size experts fear could lead to major regional damage.
At the moment, there are no large asteroids that could hit Earth. If they do find one, the second phase kicks in. This is where they attempt to stop humans from following the footsteps of the dinosaurs.
A few methods have been tested by potential planetary defenders to move an asteroid from a collision course with Earth. DART is used to test one known as a "kinetic impactor". This is a fancy term for hitting a large enough mass at high enough speed to push an asteroid off a dangerous path.
The $330 million mission DART will be launched aboard a SpaceX Falcon 9 rocket, from Vandenberg Space Force Base, California. Launch opportunities will continue until February 2022, with launch windows opening on Wednesday, November 24, at 1:20 AM EST (0620 GMT) and Tuesday Nov 23, at 10:20 PM EST.
Artist's rendition of the DART spacecraft with its cubesat partner at the Didymos Asteroid System. (Image credit: NASA/Johns Hopkins, APL/Steve Gribben)
DART will reach a near-Earth system of asteroid systems in the fall. It will consist of Didymos which measures 2,500 feet (780m) across and a smaller moonlet. The moonlet, originally called Dimorphos is 525 feet wide (160 m). It is bigger than One World Trade Center, but it is not nearly as large as the Burj Khalifa in Dubai.
DART is more literal than spacecraft, and Dimorphos is DART’s true target. DART will launch itself into Dimorphos. Scientists have estimated that the maneuver will speed up the moonlet’s orbit of nearly 12 hours by at least 73 seconds and possibly even 10 minutes.
DART's cubesat will fly with DART to monitor the spacecraft's collision. Ground-based telescopes will be used to observe the impact on Dimorphos and the effect it has on Didymos' orbit. The European Space Agency will launch a probe named Hera in a few years to examine the aftermath of the collision.
DART, the mission team hopes, will provide scientists with their first data on how a kinetic-impactor approach to planetary defence might work in real life and not in models.
Chabot stated that asteroidoids can be complex. They look different. There are boulders, rocky parts and smooth parts. We need DART to perform a real-world test on an asteroid.
