Overview

The objective: Diverting the trajectory of an asteroid. In doing so, NASA was hoping to determine whether we have the technological capabilities necessary to alter the course of a life-threatening object on a collision course with Earth. NASA guided the small DART craft to a remote region of space and crashed it against a body only 160 meters (525 feet) in diameter. Mission accomplished! On October 27, 2022, the first planetary defense mission in history was completed. NASA’s DART spacecraft collided with the surface of the asteroid Dimorphos, a natural satellite of a larger asteroid named Didymos.

The science and other stuff to know

DART is a joint project of NASA’s Planetary Defense Coordination Office Office and the Johns Hopkins University Applied Physics Laboratory. As noted, the objective is to check the effectiveness of anti-meteorite technologies. In this case, the test consisted of smashing a spacecraft against a large object to divert its course.

The asteroids DART was sent to are located 11 million kilometers (7 million miles) from our planet. Due to their location and orbit, they don’t represent any danger to us. That’s precisely why this system was chosen to carry out the mission. Because the objects are at a safe distance from us, any deviation in the trajectory of tiny Dimorphos or its companion would be entirely harmless.

The spacecraft was piloted remotely from NASA offices during its 10-month journey through interplanetary space. The optical instruments DRACO (NASA) and LICIACube (Italian Space Agency) were in charge of sending images to Earth to provide experts with information on their location. They also sent photos of the flashes produced by the collision, whose scientific value is immense. It is because by analyzing the trail of debris from the impact —for example, the speed and amount of ejected material — researchers can determine the properties of the asteroid. Furthermore, comparing the data after the crash with the preliminary data before the disturbance in its orbital path will help understand the celestial body’s composition and density and the impact’s magnitude.

The model used by the collaboration’s engineers to send DART on its titanic odyssey predicts a 1% variation in Dimorphos’s orbit. But to verify this, they must wait for the asteroid to complete one orbit around its companion.

So what?

A deviation of 1% may not sound like much. However, if we can identify an Earth-killing asteroid with a collision orbit early enough, we could send craft like the one used in the DART mission to divert it just a few degrees. That modest change, given enough time, ends up significantly changing the asteroid’s course, thus getting it out of our way.

The success of this mission shows that we humans can protect our fragile species from the most latent danger that has plagued this Pale Blue Dot since it existed — at least to some degree. 

What’s next?

NASA’s Planetary Defense Coordination Office has several programs dedicated to observing and detecting potentially dangerous bodies. Their characterization is based on their threat to Earth, and technologically viable strategies are being developed to avoid or mitigate the effects of direct asteroid impacts.

Scientists are concerned about increasingly massive satellite constellations and the growing space debris in low and medium Earth orbit. The accumulation of artificial orbital objects makes it difficult to observe small, opaque, and distant bodies such as asteroids, slowing their detection and decreasing our chances of stopping them.

For now, no objects of these characteristics have a scheduled visit to our planetary jurisdiction. Let’s hope things stay that way.