Can We Use An Asteroid’s Own Dust to Deflect It?

Deflecting potentially hazardous asteroids (PHAs) is one of humanity’s most critical long-term efforts to ensure we don’t suffer the fate of the dinosaurs. There are plenty of suggested mission architectures to move a PHA out of the way, the most famous of which was the Double Asteroid Redirection Test (DART), which successfully changed the orbit of Dimorphos, a harmless small asteroid. That proof of concept bodes well for our chances of deflecting any future PHAs as long as they are discovered in time. But when it comes to the safety of the planet, we can’t be too careful, so developing more ways to deflect a PHA is better, and a paper from researchers at Beihang University details a methodology that is gaining some traction lately – using an asteroid’s regolith as a propellant.

The paper details a mission known as deflecting an asteroid by dusting (DAD) and describes a potential proof-of-concept mission to Apophis. This asteroid recently captured the imagination as potentially hazardous, though it has been proven to be no threat to Earth lately. As part of the mission design, the paper describes a seven-step process.

First, an orbiting spacecraft would assess potential landing sites that might be good for dust collection and for the orbital mechanics of the thrust redirection efforts. A lander would then descend and characterize the asteroid’s internal structure, including assessments for any elements that might provide a higher level of thrust. 

Finding a PHA is the first step in moving it, as Fraser discusses.

The next step would be to complete a full 3D model of the asteroid’s surface, followed by using a high-powered laser to force the dust off the surface and into a storage tank. In the storage tank, the dust would be pulverized even more, with a thruster motor pushing the dust out from the rover in a direction that causes thrust against the asteroid’s surface, thereby changing its orbit.

The dust thrust deflection would be monitored from Earth, and an orbiting probe would be used to close the loop. If necessary, several other autonomous rovers could make their way along the asteroid’s surface, coordinating their thrusting efforts to increase the deflection force. 

All this requires a lot of new technologies, coordination, and testing to become a reality. The authors suggest a potential test case to be ready for the close approach of Apophis in 2029. However, even if a lander is prepared and ready for that time, it could take upwards of 20 years for a perceptible deflection to happen – assuming that nothing goes wrong with the system in that time frame. Any engineer will tell you that having a system operate non-stop for 20 years is almost unheard of, though admittedly, some space probes are the exception to that.

Fraser discusses ideas to stop a potential asteroid strike.

One major advantage of this technique, though, would be its dual use as a proof of concept for asteroid deflection and mining. Many of the technologies would overlap, and there would be an incentive for governments and non-profits to invest in a potentially world-saving technology—at least more so than for them to invest in an as-yet unproven mining technology.

For now, this idea remains on the drawing board. But, if there is ever a real push to try out different methods of asteroid redirection, it could crop up again, especially if it’s supported by one of the major space agencies. And humanity might even get the benefit of a fully functional asteroid miner out of it.

Learn More:
Santos et al. – Conceptual Design for Deflecting a Potentially Hazardous Asteroid with a Space Duster
UT – How to Deflect an Asteroid with Today’s Technology
UT – Asteroid Detection, Deflection Needs More Money, Report Says
UT – If You’re Trying to Prevent an Asteroid Impact, the Technical and Political Challenges are Staggering

Lead Image:
Artist’s conception of the mission architecture, including the asteroid space duster (ASD).
Credit – Santos et al.