'My youngest son is three and he thinks I go to space every day'

The British astronaut was part of the recent Endeavour shuttle mission, and knowing that his family could see the lights of the International Space Station shining 220 miles above Earth made being apart from them just that little bit easier.

"My children have grown up with me working at Nasa and like most kids they take it all in their stride," says the 45-year-old. "To them being an astronaut is just like any other job, but the oldest two like to look out on nights when the station is visible.

"The only problem was with my youngest son. He's only three and he thinks I go to space every day. When I didn't come back each night for two weeks he did begin to wonder if something had gone very wrong."

During the 13-day mission Dr Patrick and a team of five other astronauts orbited the planet more than 200 times, covering a distance of more than five million miles. The launch was delayed by 24 hours due to bad weather, but when the call finally came, he meticulously went through all the pre-flight checks and just before leaving grabbed a tub of marmite and a jar of his mother's marmalade. Everyone, he says, needs home comforts, especially in space.

"This was my second shuttle flight and the launch was every bit as thrilling as the first," he says, speaking from Nasa headquarters in Houston. "You feel a real heightened sense of awareness and the adrenalin rush is incredible. It takes eight and a half minutes to reach the Earth's orbit. I guess that's when you know everything is going to be ok. You can't exactly hold your breath until then, but as each minute ticks by you settle into the flight."

When he joined Nasa 12 years ago, Dr Patrick became one of only a handful of British astronauts in the history of the space progammes. He adapted quickly to the rigorous training programme, but his latest mission represented a new challenge.

Along with fellow astronaut Robert Behnken, Dr Patrick completed his first space walk as the pair fitted a capsule, complete with domed observation deck, to the existing research station, which is used to test equipment and systems needed for future missions to Mars.

"They really are the most fantastic set of windows we've ever had in space and the view is pretty incredible too," he says. "It's funny a lot of people think that space must be this incredibly quiet place. I'm sure it is, but on the shuttle there's always noise from the fans needed to keep the air circulating, so it never feels particularly peaceful.

"However when you look out and see a world without borders, it does put things into perspective. We were moving at 8km a second so every time you looked out there was something new to see and getting the chance to complete a space walk was a real privilege.

"All the training we do is tricky, but preparing for a space walk is really physical. It's a bit like learning to ski because you have aches and pains and constant falls, but after a bit of practice it starts to feel natural and that's vital when you get out there an do it for real.

"There is a sense of being disconnected from the world when you are up there, but there's not a lot of time to stop and think.

"Every five minutes of your time is accounted for. You might not know what day of the week it is, but you know what job you've got to do next. Sometimes you do look down to Earth and think, 'Oh look it's night time down there, half the world's asleep', but then there's always something to do, something to check."

The US space programme has been the subject of much debate in recent months. As the sub-prime mortgage crisis turned into a full-blown recession, the billions spent on attempts to boldly go where no man, monkey or dog has gone before have come under increasing scrutiny.

While Barack Obama has pledged $6bn to Nasa over the next five years, with the aim of getting astronauts to Mars by the mid 2030s, his decision to scrap the Constellation programme to replace the ageing shuttles has not been popular. Thousands of jobs may well be lost in the process and with just four more shuttle flights left, Dr Patrick knows he's witnessing at first hand what is undoubtedly the end of an era.

"I don't feel like I'm making history, but I do feel privileged to be able to witness a really interesting part of space exploration history and to be just a little part of this great endeavour," he says. "I know I won't be alone looking back on the shuttle era with fondness. I have great respect for all the people involved in their design, building and built and operation and I feel incredibly fortunate that I got to stand on their giant shoulders."

Dr Patrick now lives in Connecticut, but when he was accepted into Nasa's Class of '98 it was the completion of a journey which had begun thousands of miles away, in Yorkshire, many years before. Spending his early years at Ingleby Manor, near to Great Ayton, the village where Captain Cook was born, tales of the great explorer inspired his own sense of adventure. When he gathered with his family to watch the Apollo moon landings his fate was all but sealed.

"The idea that anyone could be that far away from home was almost incomprehensible and I do remember wondering how they were all going to get back safely," he says. "But the really amazing thing was they had just done it and I grew up believing that there was a chance we would all go to the moon one day.

"I definitely wanted to be a part of that, but I also wanted to be a boat designer and a pilot. I don't think I ever set my mind on specifically becoming an astronaut, it's just the way my career took me."

After graduating from Cambridge University with a degree in engineering, Dr Patrick moved to America. His head told him that was the best place to become an aerospace engineer; his heart also told him he might still make it as an astronaut.

The week-long interview for Nasa was gruelling and years of training and work in related departments followed before he got the call that would see his childhood dreams fulfilled.

"When the secretary of the chief of the astronaut office phoned, my first reaction was, 'Oh no, I must be in trouble'," says Dr Patrick, who at the time was designing the shuttle's display panels. "When they asked if I would like to be part of a shuttle flight, I didn't hesitate. Of course the answer was yes.

"That's when the hard work begins, but the training paid off. There's nothing which can prepare you for going into space that first time, but there are things that you can do to remove the sense of novelty. By the time launch day comes round you have a clear sense of how things are going to pan out. That's incredibly important because during those first few minutes you can't really afford to have anyone on board who is distracted by the sheer novelty of the experience."

Dr Patrick hopes to fly on one final shuttle mission before the spacecraft are consigned to history, but ultimately he has even grander plans.

"I would really like to do a six- month mission," he says, before adding that his wife's permission will be sought before he signs on any dotted line. "It's a big commitment, not least because it would involve a two-year training programme in Russia.

"We'll just have to see how things work out, but whatever I ended up doing I am in no doubt that space exploration has to continue. Over hundreds of years, humans have broadened their frontiers and there are now very few places on this planet which haven't been discovered and studied in detail.

"The only areas left for explorers are deep down in the oceans and up into space and it's only by finding what's out there that we can begin to piece together the jigsaw of the world we live in."