It is stressful orbiting space, so astronauts have to seize any opportunity for fun – and for Richard Searfoss, veteran of three space missions, that came from watching novices getting to grips with their weightlessness. "They tended to move around too quickly so they would float into walls and hit their heads," he says. "It was always fun to play jokes on them."
A taste for teasing is one of the lesser known necessities for a stable space trip. "My philosophy when I became commander was that we have to take our work very seriously but not ourselves," says Searfoss, 57. "If you build a culture of fear of ever making a mistake, it is no good so you need a measure of humility."
He demonstrated this philosophy on one new colleague during a pre-flight food tasting session, when the astronauts choose their menus for an expedition. "This guy was really picky and rejected every third dish that he tasted, so I took note of what he disliked the most and had the lab change his choices to those. I then had my menu replaced by his. When we were in orbit we all enjoyed watching his horror when he opened his colour-coded meals, then, before it became too heated, I swapped mine with his."
The son of a US air force pilot, Searfoss grew up during the US push for the moon and set his heart on space exploration as a child. He graduated from the US air force academy in Colorado with a degree in aeronautical engineering and completed a master's in aeronautics at the California Institute of Technology. After 10 years as a fighter and test pilot in the air force, he was one of 23 would-be astronauts selected by Nasa from 2,500 applicants.
It's a rigorous technical, physical and mental selection procedure which includes some unexpected medical taboos. A previous history of kidney stones immediately disqualifies a hopeful, for instance, because of the buildup of minerals in the body during a flight. And personality traits can be almost as crucial as technical expertise. "The sort of stuff you learn in preschool is what counts," Searfoss says. "Team work, getting along with other people, a willingness to subvert your ego – it's a fine line between personal ambition and recognising that you can't do any of it without team support."
When Searfoss first commanded an expedition, he was warned to be aware of the "matrix".
"I was told that this was the relationships between everyone in the crew," he says. "They will take care of the technical side if you keep their morale well oiled. If I could go back 30 years I would definitely be more people oriented. At the time I was technically oriented and saw everything in black and white, but being shut in a space ship with a team of others certainly teaches you about human nature."
Surprisingly, it was wonder rather than fright that Searfoss felt on his first mission in 1993. "Once you're in orbit you've already finished the most dangerous part of the job, which is the launch," he says. "For the first 45 minutes I couldn't see anything because I was strapped in and we were nose high, but when I got out of my seat the shuttle was upside down and I saw a panorama of some desert part of the world and it was so spectacular that I wondered how I was ever going to get my work done because I just wanted to stay glued to the window."
Searfoss retired from Nasa in 2003 and is currently test piloting commercial space flights. He also designed the spacecraft cockpit for the Tom Cruise film Oblivion and advised the Hollywood star and his fellow actors on realistic dialogue and movements while in orbit.
Only those with an unwavering passion – as well as a degree in engineering, natural sciences or medicine and at least three years of related professional experience – should consider space travel beyond the big screen, he says, for quite apart from the intensity of the work, both training and missions involve prolonged absences from family. "The most challenging emotional aspect was saying goodbye to my kids when I went into quarantine a week before a flight," he says.
Nasa only selects 20 candidates from about 4,000 applicants every two years, and the European Space Agency has only recruited three times since its foundation in 1975, although it urges anyone interested to start gaining qualifying experience now in time for the next unspecified round. Those motivated by the perceived glamour of space travel will swiftly be weeded out. "You don't do it to be a hero," Searfoss says, "but because you love the technology and the science."'
It is this commitment to the practical aspects that enable astronauts to keep a level head in the face of their own mortality.
"I experienced an emergency on the launch of my second mission when the hydraulics failed and the alarms sounded," Searfoss says. "But my philosophy is that if anything goes wrong it will either be one part of the system and there are very clear procedures to fix it, or else it will be like Challenger [the space shuttle that disintegrated on launching in 1986] and there'll be nothing you can do.
"It's always in the back of your mind that you might die, but fear is a good thing – it keeps you sharp."