Japan's space agency said Wednesday its Hayabusa2 probe has departed from an asteroid after completing its mission of collecting samples and will consider releasing them at a height equivalent to the distance between Earth and the Moon.
The probe's homeward journey, previously scheduled to start by the end of the year, was brought forward to Wednesday morning after it successfully accomplished its planned tasks. It will travel around 800 million kilometers to deliver the samples to Earth in November or December next year.
One option for the delivery is having the space probe drop a capsule containing samples from the Ryugu asteroid at a height of around 400,000 kilometers to avoid the Earth's gravitational pull and disruption of its trajectory, the Japan Aerospace Exploration Agency said.
(Image of Hayabusa2 space probe and the Ryugu asteroid)[Courtesy of JAXA]
"We will be targeting a point on Earth," the probe project manager Yuichi Tsuda said.
JAXA had initially planned for a similar operation with the first Hayabusa, which unintentionally ended up entering the Earth's orbit.
Hayabusa2 was launched to discover clues about the formation of the solar system and the origin of life, with the asteroid's subsurface rock, unaffected by solar flares, believed to have retained the same state since the solar system was formed 4.6 billion years ago.
The released capsule is projected to land in the desert of southern Australia, JAXA said.
"We're grateful to (the Hayabusa2) for fulfilling its challenging endeavors and we would like it to carry on with its final task," JAXA's mission manager Makoto Yoshikawa said.
Although the Hayabusa2 will keep clear of the Moon, there are options to release the samples from near its orbit.
"This is what we wanted to achieve with the first Hayabusa's mission," a JAXA source said.
Hayabusa2 began traveling away from Ryugu at a speed of around 0.09 meters per second and will continue to take images of the asteroid.
The space probe will adjust its position when it is 65 km from Ryugu, a distance beyond the asteroid's gravitational pull. It is expected to do so sometime around Monday.
The probe will then test its ion engine, its main source of propulsion, through Dec. 2 before accelerating and traveling to Earth's vicinity.
With more than 110 papers already published based on the Hayabusa2's findings, the data collected from the space probe are expected to continue to be used to support Japan's research on asteroids.
The Hayabusa2 will go on another mission once the samples are released to Earth.
Launched in December 2014 from the Tanegashima Space Center in southwestern Japan, Hayabusa2 reached Ryugu in June last year.
The probe touched down on Ryugu twice and succeeded in collecting the first-ever asteroid subsurface samples after creating an artificial crater by shooting a copper projectile at the asteroid.
If organic matter is found in the samples, it could lead to a potential breakthrough in looking at the formation of the solar system and life on Earth.