'However, if I can be a role model for young girls and women in Japan as the first Japanese woman to fly to the ISS [International Space Station] and work as a mission specialist in space, then I am very happy to have that honour.

'I certainly hope other women will follow me in my footsteps,' she added. 'I would like to encourage young women to keep up with their interests and pursue their careers throughout their lives.'

Yamazaki left Jaxa as she is expecting her second child at the end of the month and hopes her nine-year-old daughter, Yuki, and her new child will also follow their dreams, no matter how far that takes them.

'When I was a child, I liked to watch the stars in the sky, which made me interested in space,' she said. 'I also liked to watch science-fiction movies like Star Wars, and I believed that we would all go into space when we grew up.

'At the time, I was interested in becoming a schoolteacher, so when I found out that a teacher, Christa McAuliffe, was going to be an astronaut on board the space shuttle Challenger, I felt that it was possible for space and teaching to be connected.'

After earning a bachelor's degree in aerospace engineering from the University of Tokyo in 1993 and a master's degree in the same subject in 1996, she joined the National Space Development Agency, the predecessor of Jaxa.

Yamazaki was involved in a series of development projects, notably of the Japanese Experiment Module system and the ISS centrifuge.

Selected in February 1999 as an astronaut candidate, she received astronaut certification in September 2001, was approved as a flight engineer at the Yuri Gagarin Cosmonaut Training Centre in Russia in May 2004, and was certified as a mission specialist at Nasa's Johnson Space Centre in February 2006. The training, she admits, was tough.

'We had to learn many things during the astronaut-candidate training; how to fly a T-38 jet airplane, how to survive in the sea, how to communicate in English and Russian, and of course, I had to learn the space shuttle and ISS systems.

'The hardest part for me was going through the high-intensity training and doing everything in a second language. It was like school and challenging, but it was also fun.'

Being an astronaut is a 'very equal-opportunities profession', she said, with men and women expected to train and work equally. The only added element was making sure that she got the balance between her work and the family right - and she says the support and understanding of her husband, Taichi, were important.

Yamazaki was launched into space aboard the shuttle Discovery in April last year to help in the assembly of the ISS. The STS-131 mission delivered more than 6 tonnes of supplies to the station, including scientific experiments and spare parts.

During the 15 days of the mission, Yamazaki's major role was as loadmaster managing the transfer of all the supplies to and from the logistics module. The transfer took more than 100 hours to complete. She also operated the space shuttle's robotic arm to inspect for damage to the wings or nose and used the ISS's arm to berth and unberth the Leonardo Multi-Purpose Logistics Module to and from the station.

'It was breathtaking,' she said. 'The mission was very busy, but whenever I had a chance to look through the window, I felt the Earth was so beautiful, and it looked alive.'

Back on Earth, she was in great demand as a public speaker. And she was heartened by the number of girls and young women expressing an interest in becoming involved in space programmes.

Some hurdles do remain to be overcome in Japanese society, she believes, before true equality can be achieved.

'The cultural barriers seem to still exist but there are lots of choices now for women, for example working or staying home or both,' she said.

'However, there are not many choices for men. I would say that if men have more flexibility and can achieve balance between work and the family, then that will help achieve true equality.'

For her part, Yamazaki aims to make exploration programmes more accessible to the public.

'Of course I miss the feeling of being in space, so I will pursue a different way of being able to go back there someday,' she said. 'It would be nice if we could travel to space more easily, as if we were just going on a family tour.

'As I wanted to become a teacher in my childhood, my ambition is to open a school on the moon someday,' she said. 'I really would like space to be more accessible to everyone in the near future.'

Female pioneers

1 Soviet cosmonaut Valentina Tereshkova became the first woman in space, piloting Vostok 6 on June 16, 1963.

2 Svetlana Savitskaya, also from the former USSR, was the first woman to walk in space during an expedition to the Salyut 7 space station.

3 It took the US two decades to follow suit, with Sally Ride becoming the first American woman to enter space on the Challenger shuttle.

4 In 1994, Chiaki Mukai blazed a trail in Japan by becoming the country's first woman in space.

5 Iranian-American Anousheh Ansari showed that going to space need not just be for work when she became the first woman to fly there as a tourist in 2006.