UNLIKELY as it might sound, a space probe lands on the seared surface of Venus and a man steps out into temperatures of 485 degrees C, where the atmospheric pressure could crush a submarine and where the clouds consist of hydrochloric and sulphuric acid.

He's one of five male and female astronauts on a six-year, 8.3 billion mile mission to visit every planet in the solar system and, even in a titanium suit tested in a blast furnace, he's feeling the heat too much to hang around making speeches about giant leaps for mankind.

The scene is from the opening minutes of BBC1's two-part Space Odyssey: Voyage to the Planets, a spectacular and inspirational dramatisation of a journey into space from the production team that made Walking With Dinosaurs.

This time, their special effects wizardry has been used for a dramatised journey into distant space, but the results are just as riveting.

"There's far more science fact in this series than science fiction," says producer Chris Riley. "Everything in the series is possible, if a little improbable. All the facts have been meticulously researched and we draw on the best knowledge that we have, so you can enjoy it as a drama but take away facts for the pub quiz too."

Chris is addressing a gaggle of journalists gathered in Mission Control at the European Space Agency (ESA) just outside Amsterdam, a real space HQ which doubles as Mission Control for the fictional voyage shown in the programme.

BBC researchers came here to use it as a model for their own set, but the ESA's press department saw a golden opportunity to raise their profile and invited the BBC to use the real thing for the location shoot, free of charge.

For Chris Riley it was a formidable freebie: "It gave a wonderful, realistic edge to the series. And we're competing against $100m movies here, so it was a tall order to pull something off as compelling as a top movie for a fraction of the money. Sometimes we thought we had bitten off more than we could chew."

Hollywood helped out though. Internal sets for the mile-long spacecraft Pegasus were adapted from interiors for the International Space Station as depicted in disaster movie The Day After Tomorrow; space suits and shuttle craft came courtesy of the company who supplied Apollo 13, Clint Eastwood's Space Cowboys, The Core and moonshot mini-series From The Earth To The Moon.

Writer and director Joe Ahearne has also used real footage from the ESA and from US Space Agency NASA, blending real space walks with the programme's own digital effects and stunts. "We have tried to blur the boundaries between the real missions and ours," says Ahearne.

In less skilful hands it could have been space travel's badly stitched answer to Frankenstein's monster, but the outcome is a seamlessly fused drama-documentary that exerts real tension as the crew take on highly dangerous tasks in the utmost isolation of horribly hostile alien environments.

Chris Riley also produced recently repeated astronomy series The Planets, but he feels the human drama here adds a vital extra: "The Planets told the story of 160 robotic missions to other planets but what was lacking was the human experience," says Chris.

Tom Hanks' hit 90s movie Apollo 13, telling the nail-biting survival story of the '70s moon mission which almost went tragically wrong, showed the way. "For young people, the walk on the moon - if they believe it at all - is really as remote as the Second World War. This is the series for the generation that missed Apollo," says Chris.

Perhaps it's hardly coincidental that, topping a long list of specialist advisers on the series, is Dr David Scott, Commander of the Apollo 15 moon mission.

Along with MIR space station veteran Jean-Pierre Haignr, Scott was one of the key instructors at the production's own space school, set up to train the five actors cast as astronauts in the mysteries of space travel - Martin McDougall as Commander Tom Kirby, Joanne McQuinn as geologist Zoe Lessard, Michelle Joseph as biologist and chemist Nina Sulman, Mark Dexter as medic John Pearson, and Yugoslavian-born Rad Lazar as Russian flight engineer Yvan Grigorev.

Three weeks of space school studies were supplemented by two days of intensive weightlessness training at Russia's Yuri Gagarin Cosmonaut Centre in Star City, near Moscow.

"Trying to do a series about space without going weightless would be like trying to make a scuba diving series without going underwater," says Chris.

Cast and crew endured mass nausea in exchange for the thrill and privilege of being among the tiny number of non-astronauts ever to experience the sensation.

All these efforts to make Space Odyssey realistic must have paid off. Even Chris sometimes had to pinch himself as a reminder that it was fiction. "I'd wake up in the middle of the night in a cold sweat, wondering whether I'd be able to keep the crew alive for six years..."

l Space Odyssey: Voyage to the Planets is on tonight and on November 16, at 9pm on BBC1.