Image copyright Mitsubishi Heavy Industries, Ltd./JAXA Image caption Yukinobu Sato was working as a contractor for the space agency Jaxa

A man working on a project for Japan's space agency (Jaxa) took his own life in 2016 because he was overworked, Japanese authorities have ruled.

Yukinobu Sato, aged 31 at the time, was working as a contractor on a satellite project for Jaxa and was under extreme stress, a review has said.

He had been assigned unachievable targets and was working over 70 hours of unpaid overtime a month, it added.

Japan has introduced a law to try to end the culture of long working hours.

The legislation, which came into force this week, limits overtime work to 45 hours a month and 360 hours a year in principle, the Kyodo news agency reports.

Companies that violate the rules could face fines of up to 300,000 yen (£2,046).

There were an estimated 200 deaths linked to overwork in Japan in 2017.

A lawyer representing Mr Sato's surviving family said the young contractor was working multiple 16-hour shifts.

He confirmed that "karoshi" (death from overwork) had been recognised by labour authorities as the cause of death, the Asahi Shimbun newspaper reports.

Mr Sato's employer, Software Consultant, told the newspaper it would take measures to prevent future incidents, while Jaxa said it would assess the situation to see if it could improve any of its own policies.