DART: How NASA Deflected an Asteroid

Imagine earth about 65 million years ago, on the last day of the era of the dinosaurs. An asteroid going more than 40,000 mph slams into the earth’s crust near the Yucatán Peninsula and kills more than 80% of all life on earth, including the dinosaurs. Up to this point in human history, we’ve pretty much just been crossing our fingers in hopes that an event like this doesn’t happen again, but in only the past few years, NASA has begun to uncross their fingers and prepare for a hypothetical asteroid impact.

Let me introduce you to NASA's DART mission. DART stands for “Double Asteroid Redirection Test,” and this mission was the first time human beings have ever significantly changed the course of an asteroid.

The Target:

The target of the DART mission is a binary asteroid, or a group of two space rocks in orbit, about 6.8 million miles away from our home planet. This pair consisted of Didymos, a spherical asteroid about as tall as One World Trade Center, and Dimorphos, the slightly smaller, Pyramid of Giza-sized space rock that orbits Didymos. “Didymos” means “twins” in Greek, hence the “Double” in “Double Asteroid Redirection Test”. The smaller asteroid, Dimorphos, was the target of NASA’s spacecraft. [See image]

The Ship:

The actual spacecraft, created by NASA in conjunction with the Johns Hopkins University Applied Physics Laboratory, was surprisingly small and simple. The main portion of the craft was a box approximately 3.9ft by 4.3ft by 4.3ft, with two wing-like solar panel attachments that stretched about 27.9ft on either side. All in all, it was about the size of a fully extended school bus. The entire mission cost only $313.9 million, which may seem like a lot, but is actually extremely cheap for a space mission. For reference, NASA spent $257 billion on the Apollo program.

On September 23rd, 2021, a SpaceX Falcon 9 rocket carrying the DART spacecraft launched from California’s Vandenberg Space Force Base, a branch of the US Military. The top portion of this rocket split into two pieces and broke away shortly after the launch, allowing the DART spacecraft to break free and begin its course. Though the launch did not receive much media attention, it was a huge step in the DART mission and for the protection of our planet.

The Journey:

The entire journey of the DART spacecraft was powered by its two solar panels and it was computer-controlled with help from an onboard camera. This camera, called DRACO (Didymos Reconnaissance and Asteroid Camera for Optical Navigation) took pictures of other stars and planets along the way, as well as the asteroids themselves. The camera also ensured that DART would stay on a direct course to its target. DRACO, which is a small computer, thrusters, and antennae for communication, was the only technology contained on the remarkably simple DART spacecraft.

However, DART wasn’t alone on its journey to the twin asteroids. Contained in an external, spring-loaded chamber was a second, smaller device called LICIACube, or “Light Italian Cubesat for Imaging of Asteroids” (A “Cubesat” is a small and simple cube-shaped satellite/spacecraft.) This device was built by the Agenzia Spaziale Italiana, or Italian Space Agency. LICIACube, even with its own set of extendable solar array wings, was only about the size of a purse or handbag. It was meant to take better pictures of the collision than DRACO could and send them back to earth. It was kept in its “pouch” on DART until about 15 days before the collision when it separated and began its short flight. [See image]

The Collision:

On September 26th, 2022, at 4:14 PM PST, both DART and LICIACube successfully collided with Dimorphos. Scientists watched scrutinously over the ensuing period of time for signs of the collision or any change in Dimorphos’s orbit. After studying the asteroids using telescopes, NASA concluded that Dimorphos’s full revolution time had been altered from 11 hours and 55 mins to 11 hours and only 23 mins, with a margin of error of about 2 minutes. This was an astounding success for all NASA engineers, physicists, and scientists. People across the globe cheered for NASA and the organizations that made this all possible. A google search of “DART Mission” will even display a funny animation that knocks your screen off-kilter.

So, would the DART spacecraft have stopped the asteroid that killed the dinosaurs? Probably not. But, as NASA administrator Bill Nelson said, “This mission shows that NASA is trying to be ready for whatever the universe throws at us. NASA has proven we are serious as a defender of the planet.” (Bardan, 2022)