With tonight’s launch, NASA starts getting serious about planetary defense

The Double Asteroid Redirection Test, or DART, is aboard the SpaceX Falcon 9 rocket.

A key asteroid-deflection mission for NASA will be launched from California on Tuesday night. The DART mission will attempt to demonstrate the ability to change an asteroid's position.

The 700-kg space craft is powered by ion thrusters and will rendezvous with a double asteroid in October. There is a chance that the asteroid Didymos will collide with Dimorphos. DART will hit Dimorphos at a rate greater than 6.6 km/s, aiming to slightly alter the trajectory of the asteroid, which measures 170 meters across.

If NASA succeeds in completing this test, it will be able to demonstrate the ability to stop an asteroid from hitting Earth. Thomas Zurbuchen, NASA's chief of science, said in an interview with Ars that they are trying to show that they can mitigate a threat like this.

Defense of planets.

Planetary defense is the defense of Earth from asteroids, comets, and other large bodies. In public surveys, planetary defense is one of the top choices of what NASA should focus on, and the US Congress has asked the space agency to identify all asteroids with a diameter of 140 meters or greater. That object is large enough to destroy a city.

NASA made limited progress toward these goals until about five years ago. The space agency had bigger priorities. The odds were in NASA's favor. There are no known asteroids that could hit Earth in the next century. Humans can afford to wait centuries to fully address the issue of rogue asteroids. There has never been a human death attributed to an asteroid strike.


Major asteroid impacts are very low-probability events. NASA could do something with a relatively small investment, so doing nothing seems foolish. After becoming NASA's Associate Administrator for the Science Mission Directorate in 2016 Zurbuchen tripled funding for planetary defense from $50 million to $150 million. NASA was able to fund actual projects. The DART mission is ready to fly.

Zurbuchen said that the next step is to fully fund the construction and assembly of the Near-Earth Object Surveyor mission. Within five years, 65 percent of the undiscovered asteroids 140 meters or larger will be found, and 90 percent within a decade.

The mission is subject to funding from Congress. The White House wants to start building the NEO Surveyor in the fiscal year 2022.

There is still more to be done.

Zurbuchen believes that we have a planetary defense program that is worth discussing. I'm really proud of what we've been able to do. I still think we can do better.

Zurbuchen said that if DART is a success, there is a chance that a fully fueled impactor could be built. He said that such a capability would be ready to go should an asteroid be found. The closer an asteroid can be to being diverted, the more meaningful it would be.

A small craft is inside a big plane.

The first stage of the DART mission has flown two previous missions, one for NASA in November 2020 and the other in May 2021. Liftoff is set for 10:20 pm local time from the California base.

There is a 90 percent chance of good weather for a launch. There were no issues that would prevent an on-time launch after the static fire test of the rocket.