A robotic explorer released from Japanese space probe Hayabusa2 landed safely Wednesday on the Ryugu asteroid, about 300 million kilometers from Earth, for a mission that may provide new insights into the origin of life, Japan's space agency said.

The Japan Aerospace Exploration Agency said the Mobile Asteroid Surface Scout, a small box-shaped lander developed by the German and French space agencies and known as Mascot, started its final descent from 51 meters above the asteroid after it separated from Hayabusa2.

[Supplied image by JAXA]

A set of explorers released by the unmanned Hayabusa2 successfully landed on the asteroid on Sept. 22 and the main probe itself is scheduled to touch down in late October.

"We are relieved as we were able to lead the (landing) mission to success as part of a large international team," said Yuichi Tsuchida, an associate professor at JAXA and Hayabusa2 project manager.

Hayabusa2 will remain 3,000 meters from the asteroid to receive data from the lander.

Ryugu, an asteroid estimated to have a diameter of about 900 meters, travels around the Sun once every 16 months, passing near the orbits of Earth and Mars. It is believed to contain water and raw materials for life.

Mascot, weighing about 10 kilograms, will capture images and examine temperatures and soil on the asteroid surface using four observation devices including a camera and a microscope, according to JAXA.

Powered by lithium batteries, Mascot can only move for 16 hours before it runs out of power, but unlike solar-powered explorers, it can continue its survey without sunlight.

Hayabusa2 arrived at Ryugu in late June after a more than three-year, 3.2-billion km journey. The probe is due to return to Earth at the end of 2020 after making three landings on the asteroid in a bid to collect rock samples.