The link-up with the school in Kenton, was coordinated by Nasa
Pupils from a north-west London school chatted to an astronaut in space as part of their science project.
The pupils from the Michael Sobell Sinai School in Kenton questioned Canadian astronaut Greg Chamitoff from the International Space Station.
The 180 girls and boys, aged between nine and 11, asked Mr Chamitoff various questions via a live teleconference link.
The live connection was made to the station, in orbit above Hawaii.
Head teacher Vivienne Orloff said the live link to space had enriched the children's education.
"This experience makes science real for them. It's not something that you get from a textbook."
The astronaut's cousin, 41-year-old Karen Diamond, a music publisher from Wembley, has two daughters at the school, four-year-old Amelia and six-year-old Jessica, and arranged the link-up.
She said: "It is wonderful to do this for the school and for all the other pupils as well."
Mr Chamitoff, an avid Star Trek fan, began his ambition to be an astronaut from the age of six, after visiting Cape Canaveral.
He gave some advice to pupils of the school, some of whom said they wanted to follow in his footsteps, saying: "Be the best that you can be at what you do and work very hard."
He added: "I am too old now to visit the moon as an astronaut, but I am hoping to go to the moon on holiday some day."