Science and technology minister Hagiuda Koichi says a capsule brought back by Japan's Hayabusa2 asteroid probe contained at least 5.4 grams of samples. That's more than 50 times the targeted volume.
Hagiuda spoke to reporters on Friday after observing the ongoing work to analyze the samples by the Japan Aerospace Exploration Agency, or JAXA.
A group of Japanese scientists have developed a new method to safely analyze samples from Mars by trapping microorganisms in calcium carbonate crystals.
The United States is planning to collect soil from Mars to study past life. The Japan Aerospace Exploration Agency also plans to bring back samples from Mars' moon Phobos in 2029.
Japan's asteroid probe Hayabusa2 will return a capsule containing samples from the asteroid Ryugu to Earth in early December.
Japan's education ministry announced that Hayabusa2 is scheduled to drop the capsule onto an Australian desert on December 6.