NASA prepares for the first planetary defense mission: What is DART and what will we learn from it?

NASA wants us to look up and see how a probe crashes into an asteroid to change its orbit.


There are no dangers to date, but such a mission can be decisive for the future of humanity.

At the beginning of the year, the film called ‘ Don’t look up ‘ became one of the most viewed after successfully parodying how the scientific community is sidelined in the face of critical events in which their participation is required.

The plot, in its form, showed us how an asteroid was dangerously close to Earth and how scientists warned the population, but they were ignored. In real life, although it is true that there are no risks to date of such a catastrophic event, it is possible that rocks of different sizes hit the planet, so it is preparing for a unique mission of its kind: the DART mission.

What is the DART mission?

The Binary Asteroid Redirection Test ( DART ) is an attempt by NASA to test a new method of planetary defense against an impending collision.

“It consists of studying the effects (post event) of the intentional direct impact on an asteroid . We are talking about the effects on the asteroid ‘s orbit ”, comments Dr. Nobar Baella, an astronomer from the Geophysical Institute of Peru (IGP). “We see it all the time in the movies, but does it work in real life?”

“This project is interesting because it is about seeing a way to prevent some kind of catastrophe that could happen,” says Vanessa Navarrete, a physicist at the Universidad Nacional Mayor de San Marcos, who teaches astronomy courses on her blog Let’s Talk about the Universe. “It is a planetary defense commission where NASA , the military and many research groups are involved.”

The protagonists of this mission have their own names. In addition to the homonymous ship sent by NASA of 500 kilos, Didymos and Dimorphos make up the binary system under study.

“One is Didymos , which is about 780m in diameter, and the other is Dimorphos , another small asteroid that is about 160m in diameter. They are not spheres, but rather deformed bodies, so it is not possible to predict with certainty what the impact will be like,” Navarrete describes.

They have not been chosen at random. Its behavior, Baella reminds us, is known to astronomers, so there is a basis for comparison before and after the impact.

“In a binary system we have an initial frame of reference (the shape of the orbit and its characteristics before the impact) constituted by the binary system itself. In such a way that, after the impact, we will be able to observe how the shape of the orbit was modified. Of course, because if you hit a lonely asteroid , in space, without any nearby reference frame, how are you going to detect, in a short period of time, how its orbit was affected by the “hit” you gave it?

For this, the figure of ‘the light curve’ is necessary.

San Marcos physics exemplifies this model. “When we observe an object that is orbiting another, and one of those objects passes in front of the other, it blocks part of its light, so the brightness that we perceive will arrive with less intensity.” “By measuring the light curve we will be able to know the orbital parameters of this binary system and be able to know how they changed with respect to those that we have already measured.”

DART will have eyes from many parts of the universe. In addition to the multiple telescopes on Earth, the specialist tells us that the Hubble telescope itself, and possibly also the James Webb, are active members in this event.

” DART itself has a cubesat, a small Italian satellite called LICIACube that was already released last Sunday, which will photograph the result of the impact about 3 minutes after it occurred,” Navarrete mentions. Precisely, this second probe will be located between 40 and 80 kilometers away from the impact in order to capture good photos of the event without having the risk of being hit by debris.

“They also want to look for a beta factor that characterizes the impact and is related to the mass that is impacting, to the speed with which it impacts, and will generate the response, that is, the change in position of the asteroid.”

What is written has a date and time of completion: Monday, September 26 at 6:14 in the afternoon, Peru time. “What happens is that just around that time the binary system of asteroids manages to get as close to Earth as possible. This means that observations with telescopes from our planet are of good quality”, comments the main astronomer of the IGP. “With the information collected we will be able to have a better picture if this method (direct impact) works or not. Will the current technology work? What should we improve?”

Are we in danger from asteroids?

An asteroid impact is a very serious event that could endanger all of humanity.  “We are always (at risk),” says Baella. “But asteroid specialists always speak with probabilities. You can also answer using the frequency of the event. The frequency depending on the size of the asteroid: the smaller the size, the more frequent. The larger the size, the less frequent. An inverse relationship between size and frequency”.

“Science observes the NEOs or asteroids very close to Earth and that could be dangerous to impact us,” adds Navarrete, to later provide us with statistics on the possibilities of impact against Earth due to their size:

  • For an asteroid four meters in diameter, the statistic is that it hits one per year. The interesting thing is that they disintegrate in the atmosphere, leaving a glow in their path, small meteorites reaching mainly the sea.
  • Asteroids of approximately 25 meters have a frequency of approximately one every hundred years. When passing through the atmosphere, they not only disintegrate, but also explode, being able to cause injuries as they spread.
  • Those of 160 meters in diameter, impact every 25 thousand years with the Earth.
  • Those one kilometer in diameter have statistics of crossing every 500 thousand years. These could indeed generate the collapse of civilization. About 900 have been identified.
  • Those of 10 kilometers in diameter have a frequency of 100 to 200 million years and would generate the total extinction of terrestrial life. Only 4 are known and, thanks to their dimensions, they have been identified.

From time to time, fireballs threaten our home, but many of them end up disintegrating in the Earth’s atmosphere. The astronomer tells us about the case of a meteorite that did reach the Peruvian surface in 2007. The celestial body impacted the town of Carancas (Puno) causing almost 600 people to be affected as a result of the gas emanations from the crater. with nausea and headaches.

“At the other extreme is the event that extinguished the dinosaurs (Chicxulub), caused by a body of 10 kilometers, one is expected every hundred million years”, recalls Nobar Baella regarding this last case. “It is interesting to emphasize that this extinction occurred 65 million years ago. And be careful, with those millions of years we have already ‘traveled’ a long time to get dangerously close to the moment in which another extinction of that magnitude would touch us. As to take into account, Since we are talking about probabilities, don’t you think?

Events like DART unite multidisciplinary groups for humanity, with Latinos being representative in said study. This first test will be significant for this new stage of planetary defense so, as part of society, we should be attentive to its results. September 26 will be a historic date that will mark a before and after in science and in its dissemination to communities.