Astronaut Joe Tanner is preparing for the first construction mission to the International Space Station since the Columbia disaster in 2003.
Joe Tanner is one of Nasa's most experienced astronauts
Nasa veteran Mr Tanner, whose family come from Wales, is set for his fourth space flight on Sunday.
His grandfather was a head teacher in Llanddewi-Brefi in Ceredigion.
The village became famous after being featured in the Little Britain comedy series - the home of Dafydd, who claims to be "the only gay in the village".
Illinois-born Mr Tanner, a cousin of the first National Poet for Wales Gwyneth Lewis, visited Llanddewi-Brefi primary school in 1995.
A CAREER IN SPACE
1984: Joe Tanner joins Nasa after serving as a US Navy pilot
1992: Selected as an astronaut
1994: First space mission aboard Atlantis
1997: Performs first of two space walks during a mission to repair Hubble telescope
2000: Performs three space walks during a 10-day mission to work on space centre
His mother also grew up in the area and was a pupil at nearby Tregaron High School.
A veteran of three shuttle flights and five space walks, his latest mission aboard the shuttle Atlantis will last 11 days. The six crew will resume assembly of the $100bn International Space Station.
It will be the first construction flight to the station since the Columbia disaster. Nasa has since flown two missions designed to test safety upgrades.
Father-of-two Mr Tanner is one of Nasa's most experienced astronauts and has logged more than 30 days (742 hours) in space.
His experiences partly inspired his cousin Gwyneth Lewis to write a collection of poems called Zero Gravity, which she wrote after his shuttle mission in 1997.
Meanwhile, another relation, second cousin Maelgwyn Davies, from near Aberaeron, Ceredigion, has been invited to Sunday's launch.
Little Britain's Daffyd made Llanddewi-brefi famous
"Five members of the family will be going across to see it," he said.
"Although we haven't seen each other for four years, Joe said then that his next mission would probably be his last. He wants to move into management.
"His mission will involve a space walk and he will help fit new solar panels to the space centre."
As for Llanddewi-Brefi, Mr Tanner's links with the village are genuine unlike its fictional famous son Daffyd (sic), "the only gay in the village".
However, there has been a genuine Dafydd in space. Canadian Dafydd Rhys Williams, whose family is from Bargoed, south Wales, was the first man to fly the Welsh flag in space in 1998.
Dr Williams is preparing for his second mission, although he does not yet have a launch date.