The first person the teenagers on this year's Scottish Space School meet when they arrive at their hotel in Houston, Texas, is a slim Hawaiian in jeans and a T-shirt, who joins them for their evening meal.
The leader of the schools group, Alex Blackwood of Careers Scotland, introduces the guest. "I'd like you to meet Ed Lu. He's just back from six months on the International Space Station." Twenty-five pairs of startled eyes turn to look at the affable astronaut, who gives them a smile and a wave and soon is chatting easily with the 16-year-olds from schools across Scotland.
The Scottish Space Foundation, a partnership of Careers Scotland and the Scottish Executive, has delivered a big boost to science education. For the past three years it has been taking parties of fifth years to the Johnson Space Center for a packed week of rocket science, problem-solving and socialising with spacemen. But those trips are just the tip of the iceberg.
"Schoolchildren all over Scotland take part in our science activities and workshops," says Mr Blackwood. "More than 10,000 have already met the astronauts we bring over to give presentations and chat with them in schools."
The foundation is now working with NASA to adapt the excellent educational materials it produces to the Scottish curriculum. It is hoped these will be augmented by the European Space Agency.
For the space school pupils, the focus of the Houston week is linked enterprise activities that get them working in groups to gain information, deliver presentations and build Mars roving vehicles and rockets within strict constraints of time and money. It is a demanding set of challenges that calls for ingenuity, persistence, teamwork and maturity as they learn to confront technical problems and harness varied personalities to get results.
Stimulating and satisfying though the students find the activities, the highlight of most days is rubbing shoulders with the elite band of men and women who have been in space. Bonnie Dunbar, a veteran of five space flights, has invited them for a barbecue at her beach house and Ed Lu, who has been on three space flights, has invited them as special guests to a mission debriefing for the heads of NASA. They even get to chat to English-born Mike Foale, who is spending six months on the International Space Station, and he performs back-flips at their request. (Two days later he appears on television with the US president, announcing NASA's goal of a mission to Mars.) "The guys who came last year said it would change our lives," says Lewis Allison of Inverkeithing High. "I couldn't see how, but it has. I'll go back to school all fired with enthusiasm. It has been the most amazing week of my life."
This is a virtually universal reaction from the students.
Whether attending a reception at the Consulate General or having a snack at the House of Pancakes, the space school students conduct themselves with dignity and good humour, impressing the space community and acting as wonderful ambassadors for their schools and country.
At the graduation dinner, attended by deputy first minister Jim Wallace and 15 astronauts, a speaker recalls the words of astronaut Christa McAuliffe - "I touch the future. I teach" - and commends the four teachers who have come with the Scottish pupils.
Supervising teenagers so far from home is demanding, says Jill Pringle, a physics teacher from Tynecastle High in Edinburgh. "Everyone is from different schools so it took time to get to know each other. Each day you organise, advise and sometimes comfort. It's a bit like being a parent and it's a 24 hours a day responsibility. The reward comes when you see the wonderful experiences reflected in the kids' faces."
After the graduation dinner, North Berwick High pupil Rosie Bamford accepts an award commemorating Laurel Clark, mission specialist on the Space Shuttle Columbia that broke up on its return a year ago. Rosie responds with simple eloquence: "I hope I can do justice to her memory."
Later she explains what space school has taught her about the human side of science, from the loss shared by the community when some of their number do not return from missions to the elation when a long-planned mission is crowned with success.
"We saw a film of the people in Mission Control waiting to hear from a Mars lander. You could feel the tension when no signal came for ages and they thought it might be lost. Then they were so excited when they heard it, laughing and whooping with joy. I never knew science could produce such powerful emotions," she says.
For more information about the Scottish Space School, e-mail firstname.lastname@example.org