TOKYO • Japan's Hayabusa2 probe began descending yesterday for its final touchdown on a distant asteroid, hoping to collect samples that could shed light on the evolution of the solar system.
"At 9.58, we made a 'Go' decision for the Hayabusa2 probe's second touchdown," the Japan Aerospace Exploration Agency (Jaxa) said in a statement.
By early afternoon yesterday, Jaxa said the probe had descended around 5km and was on track to touch down today on the Ryugu asteroid, some 300 million km from Earth.
If successful, it would be the second time it has landed on the desolate asteroid as part of a complex mission that has also involved sending rovers and robots.
The mission hopes to collect pristine materials from beneath the surface of the asteroid, which could provide insights into what the solar system was like at its birth some 4.6 billion years ago.
To get at those crucial materials, an "impactor" was fired in April from Hayabusa2 towards Ryugu in a risky process that created a crater on the asteroid's surface, and stirred up material that had not previously been exposed to the atmosphere.
"It would be safe to say that extremely attractive materials are near the crater," Dr Yuichi Tsuda, Hayabusa2 project manager, told reporters ahead of the mission.
Hayabusa2's first touchdown was in February, when it landed briefly on Ryugu and fired a bullet into the surface to puff up dust for collection, before blasting back to its holding position.
The second touchdown requires special preparations because any problems could mean the probe loses the precious materials already gathered during its first landing.
The touchdown will be the last major part of Hayabusa2's mission, and when the probe returns to Earth next year, scientists hope to learn more about the history of the solar system and even the origin of life from its samples. At about the size of a large refrigerator and equipped with solar panels to keep it powered, Hayabusa2 is the successor to Jaxa's first asteroid explorer Hayabusa - Japanese for falcon.