Japan's Hayabusa2 successfully touches down on asteroid Ryugu to collect rock sample

Probe expected to return in 2020 to bring the rock sample back to Earth

Japanese spacecraft Hayabusa2 has successfully touched down on asteroid Ryugu in an attempt to collect rocky material from its surface.

A live webcast of the Japan Aerospace Exploration Agency's (JAXA) control room showed dozens of scientists monitoring the data before exploding into applause after they received a confirmation signal that Hayabusa2 had successfully landed on asteroid's surface.

"National Research and Development Agency/ Japan Aerospace Exploration Agency executed the asteroid explorer Hayabusa2 operation to touch down the surface of the target asteroid Ryugu for sample retrieval," JAXA said in a statement.

"Data analysis from Hayabusa2 confirms that the sequence of operation proceeded, including shooting a projectile into the asteroid to collect its sample material. The Hayabusa2 spacecraft is in nominal state. This marks the Hayabusa2 successful touchdown on Ryugu."

The touchdown happened on Thursday evening at around 11:30 pm GMT. Earlier, JAXA had delayed the descent for about five hours.

Ahead of starting to descend from 20km above the surface, the craft dropped a 'target marker' on to the surface to be used as a guide.

After successful landing, the probe fired a 5g tantalum pellet into the surface at a speed of 300 metres/second to kick up the dust, which scientists hope should have been collected by the sampler horn present in the craft's underbelly. Because the sampler instrument is one metre long, it was vital that the touchdown site has no rocks more than 50 centimetres in height.

"We made the ideal touchdown in the best conditions," said Hayabusa2 project manager Yuichi Tsuda.

Hayabusa2 was launched in December 2014 and arrived at Ryugu in June 2018.

The one-kilometre-wide asteroid Ryugu is located about 300 million kilometres from Earth and is classified as a primitive C-type space rock. Scientists believe this relic, which dates back to the early days of our Solar System, could provide significant information about the conditions that prevailed when Solar System had just formed.

The touchdown operation was originally planned for October 2018, but it was delayed for a few months after JAXA found that Ryugu's surface was much more rugged than expected. It took JAXA almost four months to find a suitable location on the asteroid for sample collection.

The probe is expected to return to Earth with the collected sample in 2020, when it will drop the sample packet in Woomera, Australia, on a fly-past.