Photo/IllutrationA press room monitor shows applause breaking out in the control room of the Sagamihara complex of the Japan Aerospace Exploration Agency on July 11 after confirmation was received that the Hayabusa 2 space probe made a second landing on the asteroid Ryugu. (Ryo Ikeda)

  • Photo/Illustraion

The Hayabusa 2 space probe has landed on the asteroid Ryugu, but scientists were still waiting to see if it collected underground samples that could provide clues on how the solar system was created.

Officials of the Japan Aerospace Exploration Agency (JAXA) announced around 11 a.m. on July 11 that they had received data confirming Hayabusa 2 made its second landing on the asteroid about 240 million kilometers from Earth.

After it descended to about 300 meters above Ryugu, the probe was no longer under the control of JAXA scientists. It made the final descent based on information gathered from equipment on-board.

JAXA officials said they had also observed signals indicating the probe had risen from the surface as planned. But final confirmation will take more time because data sent by Hayabusa 2 reaches Earth in about 13 and a half minutes.

The probe first landed on Ryugu in February and is believed to have collect samples of surface sand and rocks. In April, Hayabusa 2 dropped an explosive on the asteroid to create an artificial crater.

The second landing near that crater is intended to collect what JAXA hopes are the world’s first underground samples from an asteroid. JAXA scientists had also confirmed that the probe fired a bullet into the surface to kick up sand and rocks for collection by the probe.

“The probe worked so perfectly that it felt like a rehearsal,” Takashi Kubota, a JAXA senior project member, said about the day's developments.

If the second collection is successful, Hayabusa 2 will have far surpassed its predecessor, but it still faces the difficult task of returning to Earth in as intact a condition as possible.

Some within JAXA had suggested aborting the second landing and having the probe return to Earth with the samples collected from the first landing.

There were concerns about the risk of losing the surface samples if the probe was damaged on the second landing, making its return to Earth more difficult.

Hayabusa 1 was damaged when it landed on another asteroid, the Itokawa, in 2005.

But JAXA scientists learned from that first mission and conducted numerous simulations using the successor probe. They were confident that a second landing could be pulled off.

The second landing was about the last chance for Hayabusa 2 because surface temperatures on Ryugu were increasing as the asteroid’s orbit was bringing it closer to the sun.

Plans call for Hayabusa 2 to leave Ryugu by the end of this year and return to Earth toward the end of 2020.

Ryugu has a diameter of about 900 meters and is believed to contain more carbon than the Itokawa asteroid, leaving open the possibility that Ryugu holds organic substances.

Most asteroids have an orbit that is outside that of Mars. But Ryugu has a rare orbit that periodically brings it closer to Earth, making it easier to observe.

At the same time, it is classified as a potentially dangerous asteroid because of the possibility that it could collide with Earth.