As it re-enters, Mir is expected to break up into thousands of pieces, some weighing as much as 700 kg (1,500 pounds).
A final decision on when to "scuttle" the platform depends on whether a cargo ship carrying extra fuel is able to dock with Mir later this month, said Russian space agency spokesman Konstantin Kreidenko.
The unmanned Progress vessel is scheduled for launch on Thursday this week from the Baikonur cosmodrome in Kazakhstan. It will attempt to dock with the station on 22 January, Kreidenko said.
Progress vehicles have routinely docked with Mir in the station's 15 years of operation, but some have required manual steering from cosmonauts inside the station.
Russia has an emergency crew standing by to fly to the Mir in case the latest Progress flight fails to dock using the automated system.
No guarantees
After fuel from the Progress is taken on board Mir, Russian ground controllers will fire rockets on the station to slow its orbit and send the platform hurtling into the thicker layers of Earth's atmosphere.
As it re-enters, Mir is expected to break up into thousands of pieces, some weighing as much as 700 kg (1,500 pounds).
Most of them will burn up in the denser air, and the remainder will splash down into the Pacific around 1,500 km (900 miles) east of Australia.
Senior space experts have warned that there are no guarantees the hazardous ditching operation will go smoothly.
The decision to close this chapter in Russia's space programme follows several glitches in recent years, including a serious fire and a near-fatal collision with a cargo ship in 1997.
International future
On 25 December, the command centre lost radio contact with the space station, causing concern that it might spin out of control and fall to Earth at random.
According to sources within the Russian aerospace agency, the breakdown in communications, which lasted almost 24 hours, may have been caused by a faulty battery.
After considering various options aimed at prolonging the space station's operational life, Moscow decided last month that the pioneering craft had come to the end of its useful life.
Russian Prime Minister Mikhail Kasyanov signed a decree on 30 December ordering the destruction of the Mir space station as soon as was practicable.
The Russians are expected to concentrate resources on the new International Space Station.