PARIS (AFP) - An advertising stunt in which a golf ball will be whacked into orbit from the International Space Station (ISS) has met a chilly reception from scientists, who say the scheme is risky and adds to the growing problem of space junk.

Russian cosmonaut Pavel Vinogradov is to take on the role of a celestial Tiger Woods under a deal between a Canadian golf club manufacturer and the cash-strapped Russian Space Agency (RSA).

In one of three space walks planned from the ISS over the next six months, Vinogradov will climb aboard a special platform and swing a special gold-plated six iron and seek to enter the record books for the longest-ever golf drive.

If all goes well -- and NASA, the prime agency in the building and running of the ISS, gives its approval -- his ball will orbit the Earth for about four years, travelling up to 3.36 billion kilometers (2.1 billion miles) before eventually burning up upon friction with the atmosphere.

"Every single record for distance in the golf industry will be shattered," says Element 21 Golf Co. [E21], the Toronto firm behind the scheme.

Fitted with a small radio transmitter, the ball can be tracked by golf fans on their home computer, says the company, which says it will give the club to charity.

Scientists, though, are less than gleeful.

In theory, it should be easy to hit the ball for a huge distance.

After all, US astronaut Alan Shepard exulted that his two historic 1971 golf shots on the Moon, where gravity is a sixth of the Earth's, went "miles and miles and miles".

On the ISS, orbiting the Earth at a height of some 350 kilometers (218 miles), gravity is negligible and friction is zero, which should make it a golfer's dream.

But, as experienced golfers will tell you, driving that little white ball with the right force and in the right direction is a lot harder than it seems, even on a terrestrial course.

The task is that much harder in a thick spacesuit, which leaves little room for a decent swing or flexing the joints.

The ball thus could quite easily be mis-hit and travel only a couple of metres (a few feet), or be hooked or sliced and sent in entirely the wrong direction.

As a result, it could accidentally land in the same orbital plane as the ISS: station and ball would both whizz around the planet on the same track at slightly different intervals in time.

And what that means is a remote risk of a collision, capable of damaging or even destroying the ISS, depending on the angle, velocity and site of impact.

"There's a lot of room in space, but orbital mechanics is a wonderful thing, and things tend to come back to where you launched them from," said Heiner Klinkrad, acting head of space debris at the European Space Agency (ESA).

"For the ISS, the most probable collision velocity in the worst-case scenario is somewhere at 10 to 11 kilometres (six to 6.5 miles) per second.

"This thing is certainly larger than a centimetre (half an inch), which means it would certainly penetrate the shields of the space station if it hits at this speed."

Jean-Michel Contant, secretary general of the International Academy of Astronautics (IAA), a Paris-based forum on space research, suggested that Vinogradov's boots be strapped to the platform and that he make a few practice swings on a tethered ball before doing the big drive.

"If safety criteria are respected, this exercise could be useful as a teaching tool for children and students and be fun for the broad public," he said.

"But it holds out no scientific benefits... and if the worst-case scenario happens, it won't be fun at all."

Another problem is that of space junk, especially from exploded satellites and boosters, which is becoming a worrying threat to satellites and travellers.

"The international recommendations are that you should not throw out unnecessary objects, and I wouldn't qualify a golf ball as a mission-related object," Klinkrad tartly observed.

The junk region of most concern is between 900 and 1,000 kilometers (560-620 miles) above Earth, where there are many navigation, communication and weather satellites. The golf ball would be far below this height.

Bill Ailor, a director of the Center for Orbital and Reentry Debris Studies at The Aerospace Corporation in El Segundo, California, told the British weekly New Scientist there were about 300 operational satellites in this low-orbit zone.

These could in theory be at risk from the ball as it slowly spirals towards Earth, "but the chance of something like that happening is probably very low," said Ailor.

NASA spokesman Doc Mirelson said the planned golf drive was being vetted for safety by the agency's engineers. He said he was unable to say when this review would be completed.

E21 did not return phone requests for further information about the stunt.