Japan's Hayabusa2 closes in on the asteroid Ryugu, releasing a photo of the space rock from just 25 miles away.

Hayabusa2 Tantalizingly Near Ryugu

Three and a half years after the launch, Hayabusa2 finally approaches its destination. The journey took nearly 2 billion miles (3.2 billion km.) of travel, but the probe and the asteroid will soon touch base around 174 miles (280 km.) away from Earth.

Marking the journey, Japan Aerospace Exploration Agency snapped a photo of the asteroid from just 25 miles (40 km) away using Optical Navigational Camera on Sunday, June 24. At this distance, the details of the asteroid are already amazingly clear.

Hayabusa2 project manager Yuichi Tsuda describes Ryugu in the statement, saying that while the asteroid first appeared round from a distance, then square, it is actually shaped like a fluorite or an abacus bead.

"This means we expect the direction of the gravitational force on the wide areas of the asteroid surface to not point directly down," he explains. "We therefore need a detailed investigation of these properties to formulate our future operation plans."

Tsuda notes that the rotational axis of Ryugu is perpendicular to its orbit, which will is ideal for landing and operations. However, observations also indicate a peak in the vicinity of the equator as well as a number of large craters in the asteroid's surface, which makes choosing the landing points more difficult.

About Hayabusa2

According to New York Times, the mission of Hayabusa2 is to fly to Ryugu, which is an half a mile wide and located between the orbits of Earth and Mars. Observations will last about a year and a half, after which the probe will head back to Earth and drop off some samples of the asteroid.

The spacecraft uses ion engines, which is efficient, yet not very powerful, which is why the journey to Ryugu took so long.

It won't take much more time, though. Hayabusa2 will reach its destination at a distance of 12.5 miles from the asteroid. From here, it will be able to observe the Ryugu closely for over a year.

Ryugu is a C-type carbon-rich asteroid, potentially even containing amino acids. As Gizmodo notes, it has traces of water and organic material, which could be analyzed to discover more about the solar system in the distant past.

By the end of July, the spacecraft will hover more closely to the asteroid to check the gravity field. The mission also includes a couple of touchdowns to collect some material from the surface and sub-surface of Ryugu.

Hayabusa2 will set for Earth by 2019, then release a capsule with the samples during a flyby of the planet in 2020.