North Islanders may catch a glimpse of the doomed Mir space station tonight before its final, dramatic journey home.

If skies are clear, Mir should be visible to Aucklanders for up to two minutes in the northwestern sky at 7.42 pm. The 140-tonne space station will rise in the northwest, pass the Seven Sisters and travel between Jupiter and Saturn before blinking off as it passes into the Earth's shadow.

For Hamiltonians the view should be about the same, but further south things get hazier.

Wellington could catch a glimpse of Mir towards the northwest at 7.42 but it will be low in the sky and make a briefer appearance. The space station probably will not be visible for long enough for South Islanders to see it.

But if things go badly wrong with the planned deorbit, timed for 6 pm tomorrow NZT, Mir will go into freefall and watchers could catch glimpses of it for a few days as it circles uncontrolled around the globe.

Meanwhile, New Zealand maritime authorities are trying to contact a fleet of American fishing boats thought to be sailing in the Mir crash zone.

Maritime Safety Authority deputy director Tony Martin said a message was being sent to the area in the Pacific Ocean where the fleet of about 20 vessels is thought to be.

"We've been running navigational warnings for a while but we will target the area more specifically," he said.

Mission controllers in Moscow were early today due to finalise details of the schedule that will bring Mir hurtling through the atmosphere into the spacejunk graveyard between New Zealand and Chile.

Most of the space station is expected burn up as it hits the Earth's atmosphere, but up to 20 tonnes of debris could survive.

American restaurant chain Taco Bell plans a bizarre publicity stunt. It has put a floating target near Mir's re-entry point and if the core of the space station hits it, everyone in the United States will get a free taco.

It has bought an insurance policy to cover the cost.

Herald Online feature: Mir re-entry