Nasa astronauts, fresh from a 12-day space flight on the shuttle Atlantis, are at their first stop today of a UK tour.
The six-strong Atlantis crew will be in Portsmouth, visiting various attractions and giving talks, as part of the tour.
They will meet as many young people as possible, culminating in a presentation to thousands of schoolchildren from all over the country at Fratton Park football ground.
"The crew's visit to Portsmouth and the presentation to schoolchildren is intended to inspire young people, not to necessarily teach them about space exploration and physics, but to reach for the skies," said James Priory, headmaster of Portsmouth Grammar School (PGS), which has organised the astronauts' visit to the city.
"The astronauts think of themselves as ordinary people doing extraordinary things," he said.
Mr Priory added: "It is apt that Portsmouth is their first stop given the strong tradition of science at PGS and that there are so many cutting-edge aerospace and defence industries in the city and its neighbouring towns."
The headmaster said he was excited at the prospect of welcoming Mission Commander Ken Ham and his crew - Garrett Reisman, Steve Bowen, Tony Antonelli, Michael Good and British-born Piers Sellers, along with a flight director and Mr Ham's wife Michelle, a veteran astronaut, astronaut trainer and flight controller.
During the tour until July 7, the crew will also visit London, Cardiff, Durham, Newcastle and Kent.