NASA launches mission that will crash into a near-Earth asteroid

(CNN) – A NASA spacecraft that will deliberately collide with an asteroid successfully took off.

The DART mission, or Double Asteroid Redirection Test, lifted off at 10:21 p.m. PT Tuesday (1:21 a.m. ET Wednesday) aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California.

But the real test for this asteroid deflection technology will come in September 2022, when the spacecraft reaches its destination, to see how the motion of a near-Earth asteroid impacts space.

The objective of the mission is Dimorphos, a small moon that orbits the asteroid Didymos, near Earth. This will be the agency’s first large-scale demonstration of this type of technology on behalf of planetary defense. It will also be the first time humans have altered the dynamics of a solar system body in a measurable way, according to the European Space Agency.

Near-Earth objects are asteroids and comets with orbits that place them 30 million miles (48 million kilometers) from Earth. Detecting the threat of near-Earth objects, or NEOs, that could cause serious damage is a primary focus of NASA and other space organizations around the world.

The asteroid Didymos and its moon Dimorphos

In Greek, Didymos means “twin,” which is a nod to how the asteroid, nearly half a mile (0.8 kilometers) in diameter, forms a binary system with the smaller asteroid, or moon, at 525 feet (160 meters). ) in diameter, which was discovered two decades ago. Kleomenis Tsiganis, a planetary scientist at Aristotle University Thessaloniki and a member of the DART team, suggested that the moon be named Dimorphos, which means “two shapes.”

It is the perfect time for the DART mission to occur.

Didymos and Dimorphos will be relatively close to Earth – at 6,835,083 miles (11 million kilometers) – in September 2022.

The spacecraft will hit a speed of about 15,000 miles (24,140 kilometers) per hour, targeting Dimorphos, said Nancy Chabot, DART coordination leader at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland.

A camera on the spacecraft, called the DRACO, and autonomous navigation software will help the spacecraft detect and collide with Dimorphos. DRACO is short for Didymos Reconnaissance & Asteroid Camera for OpNav.

The goal of the mission is to deliberately collide with Dimorphos to change the asteroid’s motion in space, according to NASA.

LICIACube

This collision will be recorded by LICIACube, or Light Italian Cubesat for Imaging of Asteroids, a complementary cube satellite provided by the Italian Space Agency. It is the first deep space mission of the Italian Space Agency.

The briefcase-sized CubeSat will travel on DART and then deploy before impact so you can record what happens. Three minutes after impact, the CubeSat will fly over Dimorphos to capture images and video.

Video of the impact will be streamed back to Earth, which should be “quite exciting,” said Elena Adams, a DART mission systems engineer at the Johns Hopkins Applied Physics Laboratory.

“Astronomers will be able to compare ground-based telescope observations before and after DART’s kinetic impact to determine how much Dimorphos’ orbital period changed,” Tom Statler, DART program scientist at NASA Headquarters, said in a statement. “That is the key measurement that will tell us how the asteroid responded to our deflection effort.”

Mission Hera

A few years after the impact, the European Space Agency’s Hera mission will conduct a follow-up investigation of Didymos and Dimorphos.

While the DART mission was developed for NASA’s Planetary Defense Coordination Office and managed by the Johns Hopkins University Applied Physics Laboratory, the mission team will work with the Hera mission team under a known international collaboration. as Asteroid Impact and Deflection Assessment, or AIDA.

“DART is a first step in the test methods for dangerous asteroid deflection,” Andrea Riley, DART program executive at NASA Headquarters, said in a statement. “Potentially dangerous asteroids are a global concern, and we are excited to work with our Italian and European colleagues to collect the most accurate data possible from this kinetic impact deflection demonstration.”

A first class mission

Dimorphos was chosen for this mission because its size is relative to asteroids that could pose a threat to Earth, but the double asteroid system itself is not a threat to Earth.

The spacecraft is about 100 times smaller than Dimorphos, so it won’t destroy the asteroid.

“This is not going to destroy the asteroid, it will just give it a little nudge and deflect its path around the larger asteroid,” Chabot said. This means that there is no possibility of changing the trajectory of the asteroid to make it a greater threat.

The rapid impact will only change the speed of Dimorphos as it orbits Didymos by 1%, which doesn’t seem like much, but it will change the moon’s orbital period by more than a minute. That change can be observed and measured from ground-based telescopes on Earth.

Dimorphos completes an orbit around Didymos every 11 hours and 55 minutes. If the impact is successful, it will change that period by at least 73 seconds, said Andy Cheng, leader of the DART research team at the Johns Hopkins Applied Physics Laboratory.

Measuring the transfer of momentum between the spacecraft and Dimorphos will show how much it takes to change the course of an asteroid.

“If one day an asteroid is discovered on a collision course with Earth, then we will have an idea of ​​how much momentum we need to keep that asteroid from pointing at Earth,” Cheng said.

Planetary defense strategies

While there are currently no asteroids undergoing direct impact with Earth, there is a large population of near-Earth asteroids – more than 27,000 in all shapes and sizes.

“The key to planetary defense is finding them long before they are an impact threat,” said Lindley Johnson, a planetary defense official at NASA Headquarters. “The principle with all of them is to change the orbital speed of the asteroid only a small amount. Changing the speed of the asteroid in its orbit changes its orbit, so in the future, it will not be in the same place where it was going to impact the Earth.”

Three years after the impact, Hera will arrive to study Dimorphos in detail, measuring the physical properties of the moon, studying the DART impact and the moon’s orbit.

This may seem like a long time to wait between impact and follow-up, but it builds on lessons learned in the past.

Other missions

In July 2005, NASA’s Deep Impact spacecraft launched an 815-pound (370 kilogram) copper impact on a comet, Tempel 1. But the spacecraft was unable to see the resulting crater because the impact released tons of dust and ice. However, NASA’s Stardust mission in 2011 was able to characterize the impact: a 150-meter (492-foot) wound.

Together, the valuable data collected by DART and Hera will contribute to planetary defense strategies. Especially to understand what kind of force is needed to change the orbit of a near-Earth asteroid that can collide with our planet.

After analyzing the mission results, “this technique would be part of a toolbox that we are beginning to build with capabilities to deflect an asteroid,” Johnson said.