Japan to test technology to destroy 'small and fast' asteroid set to collide with Earth

Japan's space exploration agency has repurposed its Hayabusa-2 spacecraft to intercept two distant asteroids and to start testing the technology required for a man-made vehicle to destroy an asteroid that is on a collision course with the Earth.

Officials from Japan Aerospace Exploration Agency (JAXA) have not said if the Hayabusa-2 will attempt to intercept and change the course of the asteroids, but a space expert has suggested that may well happen when the craft nears both the end of its operational lifespan and its final destination - the asteroid 1998 KY26 - in 2031.

Launched in December 2014, Hayabusa-2 initially had a six-year mission to intercept the near-Earth asteroid, 162173 Ryugu. Hayabusa-2 arrived at its destination in June 2018, and surveyed the meteor for around 18 months. It also collected samples of debris by firing a pellet into the asteroid's surface and drawing in the materials that were thrown up.

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The samples were returned to Earth in a capsule that landed in the Australian outback in December 2020. Scientists are still examining the samples for clues of the origins of the universe.

After the spacecraft succeeded at its primary mission, JAXA engineers announced in December 2020 that they would use the remaining xenon propellant to enable Hayabusa-2 to carry out a fly-by in July 2026 of the asteroid 2002 CC21, which has a diameter of around 500 metres and is 12.4 million km (7.7 million miles) from Earth, before continuing to its final destination, 1998 KY26.

A nearly spherical asteroid, 1998 KY26 is 30 metres in diameter and is currently orbiting the sun with a minimum distance to Earth of around 374,000km. The spacecraft is expected to meet the asteroid in 2031, JAXA said.

"The asteroid is part of a class referred to as 'fast rotating asteroids' due to its extremely rapid rotation time of just 10 minutes," the agency said. "The 'small and fast' attribute creates a very special physical environment near the asteroid's surface, as the centrifugal force due to the rotation exceeds the gravity of the asteroid."

Nevertheless, they intend for Hayabusa to attach a target marker to the asteroid in an effort to gain a greater understanding of such bodies.

"Many asteroids of this size exist in outer space and are anticipated to collide with the Earth at a cadence of once every 100 to 1,000 years, causing significant damage," JAXA said. Ultimately, Hayabusa-2 will serve as the first phase in a Japanese or multinational effort to prepare spacecraft to intercept and deflect asteroids that are on course to strike the Earth.

Ground-based observation has failed to provide the needed information on such asteroids and a closer examination of both 1998 KY26 and 2002 CC21 "will be an additional technology demonstration that will contribute to Planetary Defence", JAXA added.

NASA's Double Asteroid Redirection Test in September succeeded in colliding with an asteroid named Dimorphos and altering its orbital path, although that meteor was easily tracked because it was large, around 160 metres in diameter, and closer to Earth.

"The plan now is to obtain as much technical data and develop experience in operations at extreme distances, and then approach this very small asteroid, which is hard to see and rapidly rotating," said Lance Gatling, a security and aerospace analyst and founder of Tokyo-based Gatling Associates.

"JAXA has not said anything about trying to alter the orbit of the asteroid, but it would not surprise me at all if they have something else up their sleeves, especially by the time that 2031 comes around," he said. "They may well try to nuzzle up alongside, if they still have enough fuel, and try to use the ion engine to change the orbit."

Data collected by JAXA would also be helpful in Japan's ambitions of carrying out mining operations on asteroids, Gatling said.

"But this is a very challenging environment, the target is small and fast but any new knowledge they are able to obtain will be very useful," he added.

This article originally appeared on the South China Morning Post (SCMP).

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