The Japan Aerospace Exploration Agency has decided to postpone publication of a detailed analysis of particles collected from the sample container carried by the Hayabusa asteroid probe.
The report had been scheduled to come out in September, but now JAXA is looking at December or later.
It will take more time than originally expected to collect the particles because they are smaller than earlier assumed, JAXA said.
Munetaka Ueno, a senior JAXA official, said the agency wants to analyze the particles with extreme care because repeating the process will be difficult.
The agency had planned to collect the particles from the container and isolate those which may have come from the asteroid Itokawa before handing them over to researchers across the country for a more detailed analysis.
Under current plans, however, it will take several hours to collect one particle measuring just a few thousandths of a millimeter in diameter, according to JAXA.
The particles were found in the container inside the capsule released by Hayabusa in June after a seven-year round trip to Itokawa.
Hayabusa, which means falcon in Japanese, made an unprecedented round trip to an astronomical body other than the moon.
After its launch from Earth in May 2003, Hayabusa returned after landing on Itokawa in November 2005. It traveled some 6 billion km, surviving a series of technological problems that often threatened its return but put it three years behind schedule.