TOKYO, Dec 4, 2020 (BSS/AFP) – Call it a special delivery: after six years
in space, Japan’s Hayabusa-2 probe is heading home, but only to drop off its
rare asteroid samples before starting a new mission.
The fridge-sized probe, launched in December 2014, has already thrilled
scientists by landing on and gathering material from an asteroid some 300
million kilometres (185 million miles) from Earth.
But its work isn’t over yet, with scientists from Japan’s space agency JAXA
now planning to extend its mission for more than a decade and targeting two
new asteroids.
Before that mission can begin, Hayabusa-2 needs to drop off its precious
samples from the asteroid Ryugu — “dragon palace” in Japanese.
Scientists are hoping the capsule will contain around 0.1 grams of material
that will offer clues about what the solar system was like at its birth some
4.6 billion years ago.
The samples could shed light on “how matter is scattered around the solar
system, why it exists on the asteroid and how it is related to Earth,”
project manager Yuichi Tsuda told reporters ahead of Sunday’s drop-off.
The material is in a capsule that will separate from Hayabusa-2 while it is
some 220,000 kilometres above Earth and then plummet into the southern
Australian desert.
They were collected during two crucial phases of the mission last year.
In the first, Hayabusa-2 touched down on Ryugu to collect dust before
firing an “impactor” to stir up pristine material from below the surface.
Months later, it touched down to collect additional samples.
“We may be able to get substances that will give us clues to the birth of a
planet and the origin of life… I’m very interested to see the substances,”
mission manager Makoto Yoshikawa told reporters.
Protected from sunlight and radiation inside the capsule, the samples will
be collected, processed, then flown to Japan.
Half the material will be shared between JAXA, US space agency NASA and
other international organisations, and the rest kept for future study as
advances are made in analytic technology.
– Two new asteroid targets –
After dropping off its samples, Hayabusa-2 will complete a series of orbits
around the sun for around six years — recording data on dust in
interplanetary space and observing exoplanets.
It will then approach the first of its target asteroids in July 2026.
The probe won’t get that close to the asteroid named 2001 CC21, but
scientists hope it will be able to photograph it as it completes a “high
speed swing-by”.
Getting so close could also help develop knowledge about how to protect
Earth against asteroid impact.
Hayabusa-2 will then head towards its main target, 1998 KY26, a ball-shaped
asteroid with a diameter of just 30 metres. When the probe arrives at the
asteroid in July 2031, it will be approximately 300 million kilometres from
Earth
And the target poses significant new challenges, not least because it is
spinning rapidly, rotating on its axis about every 10 minutes.
Hayabusa-2 will observe and photograph the asteroid, but it is unlikely to
land and collect samples, as it probably won’t have enough fuel to return
them to Earth.
Still, just making it to the asteroid will be a feat, said Seiichiro
Watanabe, a Hayabusa-2 probe project scientist and professor of planetary
science at Nagoya University.
“It’s like an athlete who scored two tries at a Rugby World Cup game
attempting to compete in the Olympics, 10 years after switching over to
figure skating,” he told reporters.
“We had never expected that the Hayabusa-2 would carry out another
mission… but it’s a scientifically meaningful and fascinating plan.”
The mission extension comes with risks, including that Hayabusa-2’s
equipment will degrade in deep space, but it also offers a rare,
comparatively cost-effective way to continue research.
The probe is the successor to JAXA’s first asteroid explorer “Hayabusa”,
which means falcon in Japanese.
That probe brought back dust samples from a smaller, potato-shaped asteroid
in 2010 after a seven-year odyssey, and was hailed as a scientific triumph.