Last month, the spacecraft hit an asteroid. This pushed the latter closer to its companion and accelerated its orbit by about 32 minutes. This is a huge event for the field of planetary defense; it means that humans can significantly alter the flight path of a potentially dangerous asteroid — especially if we are warned that it’s approaching.

When the Double Asteroid Redirection Test (DART) spacecraft crashed into the asteroid’s surface on September 26, telescopes on Earth and in space watched the action. The first data from these observatories showed that DART had achieved its goal. Before the collision, asteroid Dimorphos spent about 11 hours and 55 minutes orbiting its much larger companion asteroid Didymos. This journey now takes 11 hours and 23 minutes.

Reducing the asteroid’s orbit by half an hour is a huge victory for a mission that would consider even a 73-second change a success. Researchers believe that one reason for the large change in orbit is that the impact dislodged tons of material, creating a dramatic-looking debris plume in the process. This “recoil” gave the collision additional momentum, NASA announced.

Once the scientists have all the necessary data, the modeling will become even more intensive; they will take the information from the observatories and run it through physics simulations over and over again until they have a pretty clear idea of what happened. Thus, when the European Space Agency’s spacecraft Hera arrives at the asteroid system in a few years, researchers will have a pretty good idea of what it will find.

As exciting as these first results of the DART mission are, knowing how to move an asteroid is only part of any future effort to protect our planet from space rocks. It is much more important to know what dangers exist and to know about them as soon as possible.

“This is a 4 percent change in the orbital period of Dimorphos around Didymos… it just gave it a small nudge,” said Nancy Chabot, DART program coordinator at Johns Hopkins University’s Applied Physics Laboratory.