Schools are being invited to sign up to take part in a live link-up with British astronaut Tim Peake as he orbits Earth in the International Space Station next year.
The Cosmic Classroom event will give teachers and pupils the chance to simultaneously link-up with Mr Peake during his mission, named Principia.
The TES has partnered with the UK Space Agency and the European Space Agency for the 20-minute event, which will take place in early 2016. Registration opens today.
Teachers in the TES community will ask their pupils to come up with a way to spend 20 minutes in live, public contact with Mr Peake.
Lord Jim Knight, chief education adviser of TES Global, the digital education company, said: "This is a once in a generation opportunity, for British school teachers and pupils to make a live connection with a British astronaut in space. We want every teacher in the country to sign up now, to make it the world’s largest schools and space science event.
"The countdown to the Cosmic Classroom begins now."
Mr Peake launches on December 15. He is the first British astronaut to be selected by the European Space Agency and is due to be in space for six months.