Thousands of people flocked to an exhibition in Japan on Sunday to see a capsule from the Hyabusa space probe which was hoped to have brought asteroid dust to Earth.

Some 1,800 people were queuing in Tokyo to see the heat-proof pod, which had travelled in space with the unmanned craft for seven years, even before the exhibition opened in the morning, a Japan Aerospace Exploration Agency (JAXA) spokesman said.

More than 7,000 had visited the first public showing of the capsule by early evening, he said, adding that the space agency expects as many as 50,000 people during the five-day exhibition.

The capsule, which journeyed billions of kilometres (miles), was fired back to Earth in June.

Technical problems had plagued the Hyabusa, which at one stage spun out of control and lost contact with JAXA for seven weeks, delaying the mission for three years until the asteroid and Earth re-aligned.

When it finally latched onto the potato-shaped Itokawa asteroid, a pellet-firing system designed to stir up dust malfunctioned, leaving it unclear how much material the probe was able to gather.

Scientists hope any dust samples from the ancient asteroid in the capsule could help reveal secrets about the origins of the solar system.

The space agency has said it found "minute particles" of what it hopes is asteroid dust in the capsule, but it is expected to take months to get the final results of the analysis.

The Hayabusa project has generated great excitement in Japan.

"I was so impressed that such a small thing came back to Japan after a seven-year space journey," said one of the visitors. "It is just amazing."