Next week, researchers from NASA and the European Space Agency (ESA) will attend a conference in Rome to discuss the progress of an ambitious mission to deflect an asteroid in space.
The Asteroid Impact Deflection Assessment (AIDA)—a collaboration between the two space agencies—is designed to demonstrate that such a technique could work if we need to protect our planet from a collision with a large space object.
The target of AIDA is a double asteroid called Didymos—consisting of two bodies measuring around 2,560 and 525 feet in diameter respectively—which orbits the sun between the paths of Earth and Mars. Didymos is classified as a near-Earth object (NEO) that is "potentially hazardous."
The term NEO refers to any asteroid or comet whose orbit takes it within 121 million miles of our sun and around 30 million miles of Earth.
Those NEOs that are predicted to have a minimum approach distance of less than 0.05 astronomical units (around 4.6 million miles) and an implied diameter of more than 460 feet are deemed "potentially hazardous."
Mission operators will attempt to deflect the smaller body of Didymos—which is about the size of Egypt's Great Pyramid—using a spacecraft designed by NASA known as DART (Double Asteroid Redirection Test), which is scheduled to crash into its target in September 2022 at speeds of just under 15,000 miles per hour.
A miniature satellite known as LICIACube (Light Italian CubeSat for Imaging Asteroids) will launch with DART and be deployed before the collision to observe the moment of impact.
Subsequently, another spacecraft known as Hera—designed by the ESA—will be launched, potentially arriving at Didymos in 2027. Hera will collect data on the impact site, providing researchers with insights that will allow them to better understand the effectiveness of the collision. Hera will also deploy a pair of miniature satellites to probe the asteroid in more detail.
"The mission objective is to fully validate the most efficient asteroid deflection technique: the kinetic impactor," Ian Carnelli, Hera mission manager, told Newsweek. "NASA's DART will demonstrate the terminal guidance necessary to impact a small 160-meter diameter asteroid, which is the size representative of the most probable threat. Using ground-based observatories around the world we will also be able to measure from the ground the amount of 'deflection' it has imparted."
"ESA's Hera mission will go after the impact to complete the experiment by measuring: the mass of asteroid Didymoon (this provides the efficiency which is linked to ejecta and will tell us if this technique can be used for larger asteroids than we think today;) the shape of the crater generated by DART (this allows scientists to validate numerical impact codes;) and the physical and dynamical properties of Didymoon (this will allow us to relate the deflection on this specific asteroid to its properties and therefore being able to apply the technique to other objects, like a real asteroid impacting Earth,)" he said.
Not only will the mission help to test the viability of this planetary defense technique, but it will also provide a testing ground for new technologies.
"Our mission will test a variety of important new technologies, including deep space CubeSats, inter-satellite links and autonomous image-based navigation techniques, while also providing us with valuable experience of low-gravity operations," Carnelli said in a statement.
Currently, experts have identified more than 20,000 NEOs—the vast majority of which are asteroids—and new ones are being discovered at a rate of about 30 per week. Around 5,000 of these NEOs are defined as "potentially hazardous," but at the moment we don't know of any which have a significant chance of hitting Earth in the next century—although the odds are that a collision will occur at one point in the future.
"Earth is covered by past asteroid impact craters," Carnelli said. "Currently no asteroid poses a threat but one day it will happen again. The major risk is posed by 150-meter-class objects, we know very few of them and there are potentially hundreds of thousands somewhat close to Earth. Such an object impacting Earth would generate casualties independently from the impact location and have devastating effects on economy and society."
"The good news is that the asteroid impact is the only natural hazard we can predict and also prevent,' he said. "Our insurance policy is AIDA, by testing and validating a deflection technique we can retire the risk of an asteroid collision forever. We are the first generation of humans with such technical competences, all we need to do is test. This would be Earth's insurance policy."
This article was updated to include additional comments from Ian Carnelli.
