A modified 'space catapult' could fly to space to deflect asteroids

A new planetary defense method would see a smaller version of SpinLaunch's suborbital accelerator anchored to a near-Earth asteroid.
Chris Young
SpinLaunch's suborbital accelerator.
SpinLaunch's suborbital accelerator.


California-based nonprofit The Aerospace Corporation is developing an asteroid deflection system designed to tackle mid-sized asteroids capable of causing widespread damage on Earth.

The new system will use an asteroid's rocky debris to alter its trajectory, sending it away from Earth.

"We were looking at objects of similar size [to the Chelyabinsk asteroid] that could occur in our lifetime," Nahum Melamed, a project leader at The Aerospace Corporation, explained to Gizmodo in an interview. "And we have shown that we can deflect them with that system over about a few weeks of operation."

Deflecting asteroids with a modified "space catapult"

The Chelyabinsk asteroid broke apart over the Russian city in February 2013, triggering a powerful shockwave that shattered glass and injured over 1,000 people.

These types of asteroids are much more common than massive space rocks capable of destroying a city, but they are still capable of causing a lot of damage.

The Aerospace Corporation took inspiration from SpinLaunch's suborbital accelerator for its design.

SpinLaunch recently catapulted a NASA payload to high altitudes using its system, which uses a centrifuge mechanism to spin payloads at 10,000 g's before flinging them skyward. The company aims to eventually use its space catapult to launch small satellites and payloads to low Earth orbit with only a fraction of the fuel required for a traditional rocket launch.

Melamed told Gizmodo he set out to find out how to use a similar system to deflect an Earthbound asteroid. The Aerospace Corporation's goal is to create a simplified, smaller version of the suborbital accelerator to deflect an asteroid.

Unlike Spinlaunch's suborbital accelerator, the new version won't launch payloads into space. Instead, it will be launched into space, where it will rendezvous with a near-Earth asteroid.

When the payload reaches the asteroid, the centrifugal system anchors itself onto the space rock, extracting regolith at high speeds and flinging it outward.

Essentially, the method turns the asteroid's regolith into a means for propelling it off its current path. It would fling roughly 20 lbs of regolith at a time, ejecting it at speeds of 0.6 to 1.2 miles per second (1 to 2 kilometers per second), according to The Aerospace Corporation.

"By pushing it away from the asteroid, the asteroid will recoil and will get deflected by a tiny bit," Melamed said. "So over time, by repeating the process repeatedly over weeks and months, we should be able to deflect the asteroid."

Using this method, The Aerospace Corporation says asteroids between 30 to 60 meters in width could be deflected in weeks, while larger asteroids could take months.

Melamed also told Gizmodo that the centrifuge system could double up as a space mining device, meaning it wouldn't be useless for long periods between hypothetical asteroid threats.

Earth-based trial to take place within two years

Melamed also explained that his method would be simpler, for example, than NASA's asteroid deflection method demonstrated in its Double Asteroid Redirection Test (DART) last year, which saw the US space agency purposefully slam a spacecraft into a near-Earth asteroid.

The DART approach "is like giving a punch to the asteroid, and it gets deflected in one shot," he said. "The mission is complicated, it would take a lot of time to develop the spacecraft and get it out to space, and there is no guarantee of success."

A modified 'space catapult' could fly to space to deflect asteroids
An artist's impression of NASA's DART spacecraft.

The key difference, of course, is that NASA's method has been successfully demonstrated. In contrast, The Aerospace Corporation's is still in the early development phase — it aims to carry out an Earth-based prototype trial within two years.

Whether it works or not, though, there is no harm in developing as many asteroid deflection technologies as possible. Always best to add as much redundancy as possible to any future attempts at averting global catastrophe.

Today, NASA points out that there are no known asteroids that pose a threat to Earth within the next 100 years. However, a handful of large space rocks were detected at the last moment in recent years, indicating that it's better to be safe than sorry.

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