When NASA's Double Asteroid Redirection Test slams into the tiny asteroid Dimorphos, it will be our first attempt to demonstrate our ability to protect ourselves.

Scientists have been looking for potentially hazardous asteroids in the sky for decades. As the number of near-Earth asteroids increases, attention is turning to how we can protect Earth. To test brute force, DART will collide with the Dimorphos at 7:14pm. On September 26th.

Dimorphos is a member of a system with another asteroid, Didymos, which makes it the ideal target for us to measure our ability to dodge objects. There's no chance that the impact could cause Dimorphos to careen across space because the two rocks are bound.

There are the greatest asteroid missions of all time.

NASA's focus has been on science, but the experiment marks a change in direction. Lindley Johnson, the director of NASA's Planetary Defense Coordination Office, said that the DART mission doesn't signify a change in policy, but rather a continuation of work done so far.

"Our charter from the beginning has been to find asteroids, but also to work on the technology and techniques that can be used to divert an asteroid from an impact trajectory, should we ever find one," he said. DART is just the beginning of an ongoing program.

DART's roots go back 20 years to when scientists at the European Space Agency considered a kinetic impactor mission. Representatives from NASA and the European Space Agency had a discussion about a potential AIM mission. DART and the European Space Agency's Hera mission will follow up on each other and visit Didymos and Dimorphos to view the aftermath of the impact.

planetary scientists see DART as the beginning of our efforts to learn how to defend Earth from hazardous asteroids

Whether it's against a different type of asteroid or a gravity tractor, we will definitely look to do tests in the future. A tractor is parked near an asteroid. The small craft would be able to pull the asteroid towards it. An ion engine would be used to pull the tractor away from the asteroid.

boxy spacecraft approaching space rock

An artist's depiction of the DART spacecraft approaching the asteroid Dimorphos. (Image credit: NASA/Johns Hopkins APL/Steve Gribben)

A small asteroid could be moved by the thrust from an ion engine. The space rock could be pushed away with the help of the sun.

There are a lot of ideas.

Smaller Dimorphos-scale asteroids should be able to be shifted using these methods, but larger asteroids will need a bigger punch. PatrickMichel, a scientist at the French National Center for Scientific Research, is the principal investigator on the Hera mission.

He's not sure if we could distract such a large asteroid with just a hit on it. He told Space.com that he did not think that would work.

What could be done against a bigger asteroid? There is a threshold where we have to mention the "bad word": nuclear. It would take a lot of energy to move a kilometer-sized asteroid. Over the next century, we know almost all the 1- kilometer objects and none are threatening us.

It is possible that an asteroid could still be found on a collision course, given that there are still many space rocks to find.

There are a lot of objects that cross Earth's elliptical path. Almost all of the larger ones that could threaten civilization have been found. If they collide with Earth, an estimated 42% of them have been found. Not a single one has been found to be on a collision course with Earth.

Many ground and space-based observatories are helping scientists look. The Pan-STARRS telescopes in Hawaii and the Catalina Sky Survey in Arizona are funded by NASA to search for asteroids. NASA's NEOWISE mission has led the way in finding thousands of asteroids.

According to NASA, these searches find on average 500 large near- Earth objects each year. It will take another 30 years to find all the near-Earth asteroids that have been found so far.

NASA plans to launch the NEO Surveyor mission in just over a decade. The asteroids and comets larger than 500 feet that travel within 30 million miles (50 million km) of Earth will be searched for and characterized by the telescope.

The remaining population of asteroids will be found with the help of the NEO Surveyor.

Space agencies around the world have visited asteroids over the years. The Hayabusa and Hayabusa2 sample-return missions visited the near-Earth asteroids Itokawa and Ryugu. Hera will join the ranks of NASA's OSIRIS-REx mission after launching in 2024. Understanding the composition and internal structure of near-Earth asteroids is one of the objectives of these missions.

All eyes are on DART and its meeting with Didymos and Dimorphos. It will give us confidence that humans can protect Earth if the mission goes well.

The 21st CenturySETI has a verified account. We encourage you to follow us on social networking sites.