The two Minerva-II robots are created to take advantage of the asteroid's low gravity, making long hops across its surface. The operation started when the probe was approximately 55 metres over rough rocky surface of the asteroid, as told by the mission team.
The MINERVA-II-1 - which stands for Micro Nano Experimental Robot Vehicle for Asteroid - separated from the spacecraft at a height of around 50 m (164 feet) from the asteroid's surface.
Japan is in the process of landing two unmanned rovers on a distant asteroid, according to the country's space agency, nearing completion of a task which it has previously described as the equivalent of hitting a 6-centimeter (2.4-inch) target at 20,000 kilometers (12,400 miles) away.
So far so good, but JAXA must still wait for Hayabusa2 to send the rovers' data to Earth in a day or two to determine whether the release of the probes succeeded, officials said.
Yuichi Tsuda, JAXA project manager said: We are very much hopeful.
"We are now working to confirm if there are images capturing the MINERVA-II1 landing".
In October, Hayabusa2 will release another lander, made by the German Aerospace Center, called MASCOT.it will also hop across the asteroid in a similar way as the rovers.
The probes - which can jump to move around - will investigate the asteroid's surface by taking pictures and using other instruments. The pair of rovers, collectively known as MINERVA-II1, is attached to the bottom of the Hayabusa 2 spacecraft and will be released on September 21.
JAXA also revealed it had lost communication with the robots, writing: Communication with MINERVA-II1 has now stopped. The Hayabusa-2 will then depart in December 2019, bringing the rocks back to Earth for researchers to study.