Touch and keep going
BY THE TIME you read this there may have been big news from Japan about the analysis of soil from the interior of a nearby asteroid. Excavated in 2019, the samples were spectacularly returned to Woomera in South Australia last December, with the Australian Space Agency and other local organisations working closely with the Japan Aerospace Exploration Agency (JAXA).
Why is this such a big deal? The target asteroid, Ryugu, is of a type known to have survived from the
Solar System’s infancy, 4.6 billion years ago. Along with rock, minerals and ice, it’s rich in carbon-containing compounds, raising the possibility of finding life’s building blocks in its soil.
The interior sample returned to Earth in December is a first in the robotic exploration of asteroids. It’s significant because the Sun’s radiation modifies the asteroid’s pristine material on the surface, but not at depth. No wonder the analysis is so eagerly awaited.
The technology behind this feat is extraordinary.The JAXA spacecraft Hayabusa2 was launched in
December 2014 and rendezvoused with Ryugu in June 2018. It then spent 14 months orbiting the asteroid, during which landers were deployed and surface and subsurface samples extracted, before it departed for Earth in November 2019.
But the spacecraft itself is destined never to return home. Flying by our planet on 5 December last year at 6km/s, it jettisoned the sample capsule for landing at Woomera and continued on its way. Protected by an aeroshell, the capsule became a spectacular fireball seen by many in Coober Pedy before deploying a radar-reflective parachute. A radio beacon helped its speedy recovery soon after landing. Then, after just 44 hours in Australia, the sealed capsule was whisked off to Tokyo to be opened and its contents analysed.
However, that’s not the end of the Hayabusa2 story.The spacecraft uses highly efficient solar-electric propulsion and, with almost half its supply of xenon fuel remaining, its mission is being extended to investigate two other asteroids. It will fly by an unusual L-type asteroid (2001 CC21) in July 2026, and then rendezvous with a fast rotating micro-asteroid (1998 KY26) in July 2031.
Truly, Hayabusa2 is the gift that keeps on giving!