NASA will conduct a first-of-its-kind for humanity experiment later this month. The agency will intentionally crash a scientific spacecraft, equipped with a camera so you can see it, into a distant asteroid with a goal of changing the movement of the asteroid. This will take place on Monday, Sept. 26, 2022. The asteroid target doesn’t pose any threat to earth. The reason for doing this is to gain knowledge. Data collected would be used to study asteroid redirection should one threaten to strike the earth and in the development of planetary defense systems.

You can watch the DART spacecraft crash into asteroid Dimorphos live!

You will have the opportunity to witness history being made on Monday, Sept. 26, 2022. NASA will live stream the spacecraft collision with Dimorphos live. That stream will be available on NASA’s NASA Live web stream. It will also stream live on NASA’s YouTube channel. The live coverage is scheduled to start at 6 p.m. EDT and goes until 7:30 p.m. EDT. The time of impact is currently scheduled for 7:14 p.m. The DART mission page also has information and resources for planning a watch party for the event.

The DART mission will be captured and observed by cameras onboard the DART spacecraft, the LICIACube, and high-power telescopes on earth. (Credit: NASA/Johns Hopkins APL)

What is the NASA DART mission and what does DART stand for?

DART stands for Double Asteroid Redirection Test. The reason for the “double” is because the target asteroid is part of a dual asteroid system in which a smaller asteroid is orbiting a larger asteroid. The larger asteroid is called Didymos and the smaller is called Dimorphos.

Composite of 243 images taken by DRACO (the camera onboard the DART spacecraft) on July 27, 2022, detecting Didymos. (Credit: JPL DART Navigation Team)

The mission goal is to test what is being called the “kinetic impact technique” for asteroid deflection. In simplest terms, a spacecraft will accelerate to a very high speed and slam into the asteroid. The impact speed is estimated to be around 15,000 miles per hour. After impact, scientists will study what happens.

One of the ways they will study this is via instruments that are onboard the spacecraft. The Italian Space Agency contributed a piece of equipment called the “LICIACube” which will deploy from the vessel between two to 10 days prior to impact. The cube-shaped vessel has two cameras to capture images and data about the impact, in addition to its own propulsion systems to maneuver the object into position. NASA reports that the satellite will fly by the asteroid roughly three minutes after impact, capturing details of the location of impact and any debris plumes from the impact. The DART spacecraft is also equipped with a camera that is intended to capture images up until the impact and also capture images of the surface of the asteroid just before impact in very high resolution.

Illustration of NASA’s DART spacecraft and the Italian Space Agency’s (ASI) LICIACube (lower right corner of the image) prior to impact at the Didymos binary system. (Credit: NASA/Johns Hopkins APL/Steve Gribben)

The spacecraft launched on Nov. 24, 2021. NASA says it is the size of a small car and will send images back at a rate of around once per second. The asteroid targets are roughly 6.7 million miles away from earth. NASA outlines three specific goals they hope to attain: (1) Conduct a demonstration of this type of asteroid deflection technique; (2) measure what happens, specifically targeting a two-asteroid system that allows for orbit comparisons between the two objects; (3) study the impacts a high-speed collision has on an asteroid and use that to improve/compare scientific models for this type of scenario.

NASA’s Double Asteroid Redirection Test (DART) spacecraft sets off to collide with an asteroid in the world’s first full-scale planetary defense test mission. Riding atop a SpaceX Falcon 9 rocket, DART took off Wednesday, Nov. 24, from Space Launch Complex 4 East at Vandenberg Space Force Base in California. (Credit: NASA/Johns Hopkins APL/Ed Whitman)

Didymos & Dimorphos: the target asteroid and why NASA chose it

The target asteroid for this mission is named Dimorphos. The asteroid measures approximately 163 meters, or 535 feet across. To put that into perspective, the Washington Monument in Washington, D.C. is 555 feet tall. NASA estimated the mass of Dimorphos to be 10.5 billion pounds. Dimorphos orbits a larger asteroid named Didymos. Didymos is estimated to have a diameter of 780 meters, roughly 2,560 feet. For perspective, the tallest building on earth, the Burj Khalifa in Dubai, is 2,722 feet tall.

Infographic showing the sizes of the two asteroids in the Didymos system relative to some objects on earth (Credit: NASA/Johns Hopkins APL)

So why this asteroid? Part of it has to do with it being a double-asteroid system. Dimorphos orbits larger Didymos and provides a benchmark to know the impact of the collision. NASA already knows the orbit cycle of the two asteroids. They report that Dimorphos takes 11.92 hours to complete one orbit around Didymos. NASA expects the force of the impact will result in a 10-minute decrease in the amount of time Dimorphos takes to complete one orbit around Didymos. Knowing details about the orbit cycle before impact provides a solid benchmark to use when calculating the changes caused by the intentional impact. They will measure those changes by studying observations made from earth and data sent back from the above-mentioned LICIACube that will send data back to earth after the impact.

Infographic showing the effect of DART’s impact on the orbit of Dimorphos. NASA expects the force of impact results in a 10-minute increase in the time it takes Dimorphos to orbit Didymos. (Credit: NASA/Johns Hopkins APL)

If you were curious about the names of the two asteroids, those also have to do with the dual-asteroid system. NASA says Didymos is greek for “twin.” Dimorphos is greek for “two forms.”

Are there any asteroids that currently pose a risk to earth?

As far as scientists know, there currently are not any asteroids on track to strike the earth within the next 100 years. NASA is, however, aware of many asteroids large enough to cause damage and destruction on earth that aren’t too far away. You may recall the meteor explosion over Russia in 2013. That meteor created a shockwave that shattered glass and damaged buildings in several cities. That asteroid was estimated to be only about 60 feet wide. NASA estimates the number of large and near-earth asteroids, greater than 500 feet wide, to be in the tens of thousands.

According to NASA’s Planetary Defense Coordination Office, there is an asteroid with a 1 in 714 chance of striking Earth 163 years from now. The asteroid is called 2009 FD and the year would be 2185. NASA has also completed a close-up visual study of an asteroid called Bennu. In a mission named OSIRIS-REx, a spacecraft traveled to the asteroid to study it and collect a sample of the asteroid surface. That sample is scheduled to be delivered to earth one year from now, Sept. 2023. NASA reports the asteroid Bennu has a 1 in 2,700 chance of striking earth between the years 2175 and 2195.

Are there other methods of asteroid deflection being studied?

NASA’s Planetary Defense Coordination Office reports outline three methods scientists think can protect earth from a potential asteroid strike. The DART mission is intended to study the kinetic impact technique. As mentioned above, NASA expects the collision of the DART spacecraft will only impact the orbit of Dimorphos by 10 minutes. Should this technique be employed as an actual defense mechanism, a 10-minute alteration in the track of an asteroid is really all that would be needed. According to the Planetary Defense Coordination Office, it takes earth only 7 minutes to travel the distance of earth’s diameter. So, that means speeding up the arrival time of an object approaching earth by just 10 minutes would result in it passing by just before earth arrives and slowing it down by 10 minutes would result in a near miss.

Another method NASA is looking into is called a “gravity tractor.” This sounds like something out of a Sci-fi show, but NASA believes that if a spacecraft intercepts an asteroid and is positioned right within the zone of mutual gravitational attraction between the two objects, it may be possible to alter the course. It is unclear if this technology is being studied or under development.

Lastly, the Planetary Defense Coordination Office says utilizing nuclear explosives is an option and considered a “last resort” but thought to be “highly effective for preventing a cataclysmic event.” NASA theorizes that detonating a nuclear explosion within a certain range of an asteroid would vaporize materials from the asteroid, resulting in a momentum transfer as the materials move away from the asteroid. The result, NASA believes, would be a change in momentum and track of the asteroid.