But someone else keeping a close watch on the work is also experiencing a conflict of emotions - Jane Girdlestone, whose husband Mark is one of the team of divers sent down to recover the vessel.

An experienced "saturation diver" Mark is spending up to a month working 100 metres below sea level, on the floor of the Barents Sea, off northern Russia.

And although at the end of each day's work he will be hoisted up to the support ship which sits on the water's surface directly over the nuclear-powered Kursk, he remains a prisoner of the extraordinary atmospheric conditions in which he works.

At the bottom of the sea, Mark's body experiences the pressure of the water around him, which is about 10 times the pressure at sea level.

If he remains in these conditions for more than a few minutes his body tissue becomes saturated with heliox, a mix of helium and oxygen. Were he then to rise to the surface unaided, he would suffer decompression sickness, also known as "the bends".

Mark in his work "uniform"

So when he is not working, Mark is confined to a sealed pressurised chamber that is attached to the top of the support ship. He shares the chamber, which is about the size of an average bathroom, with two Russian divers.

The three are lowered to the sea floor daily in a pressurised diving bell and at the end of their mission will undergo a four to five-day decompression.

The cramped accommodation and heavy work sound unpleasant and uncomfortable, but Mark, 42, is used to it.

For several months he builds and maintains oil rigs, platforms and pipelines on the bed of the North Sea.

Although there are similarities, Jane says that in some ways the mission to recover the Kursk is like nothing he's ever done before.

While Russian officials have been playing down the potential for danger, others are more sceptical. The Kursk, which sank after an on-board explosion, went down with 18 torpedoes and 24 Cruise missiles on board. There are fears these could still explode.

Jane hugs Mark who is posing in an old diving suit

There are also fears the nuclear reactors which powered the submarine could leak radiation if disturbed.

But everyone accepts that this is one of the most ambitious deep-sea salvage missions ever. The plan is to saw off a mangled section of the hull, which was severely damaged in the explosion last August, and leave it at the bottom of the sea.

Divers will then fix 26 steel cables to the main part of the hull so it can be hoisted to the surface using hydraulic cranes.

Usually this sort of wreck would be left undisturbed. But Russia's president, Vladimir Putin, has staked his credibility on recovering the bodies of the 118 crew who died in the disaster.

Jane says the offer of a place on the Kursk mission led to some tough questions for Mark, a father of three.

"After he probably caught his breath, part of him said 'I really want this because it's ground-breaking engineering'. Part of him, I think, thought 'Yes, this really is quite dangerous - I don't want to come back with two heads'," says Jane.

A diver enters the bell that transports them to and from the sea floor

"And part of him said he would be very proud because he wanted to actually try and help the Russian families as best he could.

"He also knows that it's not the wish of all the families to raise the Kursk but it certainly is the wish of some of them. Unfortunately, with this type of job, it's all or nothing."

"The biggest fear, for me, is radiation and the second biggest fear is that something goes wrong and there's an explosion. If there was, they would certainly lose their lives."

But the team's expertise inspires confidence in her. Mark is a practised diver who spent seven years learning his skill in the Royal Navy.

In 1982 he took part in a mission to recover the navy's first submarine, HMS Holland 1, which sank in 1913.

Things have progressed greatly in the intervening 19 years and, thanks to e-mail, Jane is able to keep in daily contact with Mark while he is working.

"These days Mark can write a letter, put it in the airlock for the operations room and they will then transcribe it into e-mail form and send it to me. I can e-mail that ship back and they can send my message back down to him.

"It's fantastic. It's really kept us together," says Jane, who recalls how even a few years ago Mark lived in a news vacuum.

"Mark must have been the only person that didn't know Princess Diana had died," says Jane, recalling how, at the time, he had been on an underwater maintenance task.

So how does he while away the hours when he is not working?

Mostly eating and sleeping, she says.

"They will be performing heavy tasks so they will be getting dehydrated. [After a shift] they will want to get back into the bell [and] immediately want something to drink.

Back in the chamber they have their meals passed to them through the airlock.

The conditions and nature of the work mean that Mark will sleep up to 12 hours after an eight-hour shift.

Mark has books and might even attempt to play cards with his Russian companions, although it could be difficult since he doesn't speak Russian.

All three of them have to be vigilant about cleanliness since bacteria can multiply quickly in those conditions. And if one becomes ill, the other two will also have to be decompressed

So far though, the mission seems to have gone without a hitch. From her home in Brightlingsea, Essex, Jane Girdlestone is hoping things stay that way.