Mir hitting closer to NZ

Mir has passed the point of no return on its journey to destruction and Russian Space Control says the space station is now likely to splash down about 300 kilometres closer to New Zealand than had been first expected.

The fiery descent is due to begin at 1820 Friday evening NZT and should last for about 15 minutes.

Pat Helm of the Government's Satellite Re-entry Committee said despite the change to the crash site, the target zone is still over 3,000 kilometres away from New Zealand.

Prime Minister Helen Clark backed up his statement, saying Mir still posed no threat to this country.

The Russians said the defunct satellite will splash into the South Pacific Ocean about 3,600 kilometres east of Stewart Island.

That takes its final orbit away from Fiji and Tonga and closer to New Zealand than originally thought.

While it is not worried that Mir will hit New Zealand, the Government is concerned about a US fishing fleet from American Samoa.

The boats have moved into the new target zone and the Satellite Re-entry Committee is trying to get word to the boats ahead of an expected crash time of 1820 Friday evening.

"We are particularly concerned about the need to get this advice to a large fleet of American fishing vessels which have moved into the area," Clark said.

"We are going to some lengths to get messages to the fleet."

Helm said that they have direct contacts for five of the boats but are having to use other means to contact up 20 other unidentified craft.

He expected the boats will get the warning in time.

Elsewhere in the Pacific, Fiji warned its 800,000 people to stay in their houses after Thursday night, not to set out to sea and to avoid any "foreign objects".

Japan has issued a similar advisory while airlines would be informed of the space station's position in case they had to reschedule flights across the Pacific.

Tahiti was paying scant attention to Mir's fiery demise as the French territory was distracted by local elections. But government officials privately complained about Russia using the Pacific as a dumping ground, residents said.

All going according to plan

On Wednesday, Mir fell as planned to within a few hundred metres of the orbit at which mission control will begin to steer it toward Earth, a spokesman said.

Mir's controllers had been waiting for the 15-year-old space station to glide to an orbit of 220km so that they can turn on its guidance systems and steer it back to Earth on Friday.

A mission control spokesman said the station had all but reached the desired altitude, after falling 4.2 kilometres in 24 hours.

Most of Mir is expected to burn up in the atmosphere, but some large chunks will still reach Earth at high speed. Russian officials plan to steer Mir into the southern Pacific Ocean to avoid striking populated areas.

They will do that by firing Mir's engines to slow it down and send it falling at the precise moment.

Officials plan to fire a first engine burst at 0333 Moscow time (1233 NZT) on Friday, followed by a second burst at 0500 (1400 NZT) and a final one at 0800 (1700 NZT).

Fragments that do not burn up will collide with the Earth between 0920 and 0930 Moscow time - between 1820 and 1830 Friday evening in New Zealand.

The external features will have burned off Mir at about 110-100km of altitude. At 50-40km, the station's main body will begin splitting apart into 1,500 pieces.

Of the 136 tonne station, about 20-25 tonnes will smash into the ocean. Careening chunks will strike the sea in a narrow streak, only about 200km wide from north to south, but stretching through 6,000km of longitude from east to west.

© TVNZ/Reuters