Tiny robots send home 1st photos from asteroid's surface

Two tiny robots dispatched to the surface of an asteroid from a Japanese spacecraft have sent home their first photos.

The Japan Space Exploration Agency confirmed Saturday that the two Minerva-II-1 rovers had landed successfully after being released from the Hayabusa2 spacecraft a day earlier.

"The two rovers are in good condition and are transmitting images and data," JAXA said in a blog post. "Analysis of this information confirmed that at least one of the rovers is moving on the asteroid surface."

Images sent back by the rovers show the asteroid's gravelly, rocky surface, and some are blurry because the robot that took them was "hopping" at the time.

The two rovers — each about the size of a small cookie tin, 18 centimetres in diameter and seven cm high — are to capture images of the asteroid and measure surface temperatures before a larger rover and a lander are released later. The rovers move by "hopping" up to 15 metres at a time because the extremely weak gravity on the asteroid makes rolling difficult. They can continue jumping as long as their solar panels and power last, JAXA said.

The spacecraft is set to release a German-French lander called MASCOT carrying four observation devices in early October and a bigger rover called Minerva-II-2 next year.

Hayabusa2, launched in December 2014, is due to return to Earth in late 2020.

The spacecraft arrived near the asteroid, about 280 million kilometres from Earth, in June. Ryugu's orbit is between Earth's orbit and that of Mars.