Russia risks losing control of its orbiting Mir space station if the Kazakh government continues to ban launches of Russian rockets that could resupply Mir, officials said today.

In the latest crisis to hit Russia's troubled space program, Kazakh officials prohibited Russia from using the Baikonur cosmodrome that Russia has rented for years after a Russian Proton rocket exploded in the air July 5, scattering potentially toxic debris across Kazakh territory.

Meanwhile, within the last two weeks, the aged Mir station, orbiting 223 miles above Earth, sprang a slow leak. Russia originally had planned to deliver more oxygen, water and equipment to Mir's three-man crew as early as Saturday, after a Wednesday liftoff, but the Soyuz rocket that will carry the cargo spacecraft is still sitting on the launch pad.

Yuri Koptev, who heads the Russian Space Agency, said the crew of one French and two Russian astronauts is not in any danger. Even if they are unable to identify and seal off the leak, the air pressure inside the station would remain at a safe level for five months, he said. The astronauts are scheduled to return to Earth next month.

But without supplies and the necessary equipment, the crew will be forced to return to Earth without ensuring that the space station can be steered from the ground, Koptev said. In that case, he said, the possibility of a malfunction would be high. "And then we will be in a situation many times worse, when a 140-ton and uncontrolled monster is bobbing up there, coming down . . . in an uncertain location," he said.

Kazakh officials are making the most of the explosion of the Proton rocket, which carried a military communications satellite. In a rare occurrence for the highly reliable Proton, one of the rocket engines malfunctioned minutes after takeoff. Television footage showed a large piece of metal that reportedly dropped into an elderly woman's vegetable garden, narrowly missing her granddaughter.

The fire resulting from the spillage of fuel laid waste to at least 1,200 acres of farmland and pasture. Koptev said most of the highly toxic fuel, heptyl, burned in the atmosphere and did not damage the land. But Kazakh officials said rivers and wells are poisoned and people may have to be evacuated.

Environmental concerns aside, Kazakh officials are clearly using the accident to make a point about Russia's failure to pay its annual rent of $115 million for the cosmodrome. The Russian media have reported that Kazakhstan owes Russia more than Russia owes Kazakhstan, but Russia is hardly in a position to argue.

It needs the launch pad, not just for Mir, but to send up commercial satellites. The commercial launches provide the financial underpinning for the cash-strapped Russian space program. For months last year, they were its only income.

Baikonur is also where the Russians plan to send up the long-delayed service module for the international space station. But the service module launch is not scheduled until November, by which time the dispute presumably will have been settled.

If Russia cannot persuade Kazakhstan to allow it to supply the Mir, the astronauts will be recalled between Aug. 15 and 20, as planned, but without completing their tasks, Koptev said. The space agency's plan called for a reconfigured Mir to continue to orbit, unmanned and steered by ground controllers.

CAPTION: The Kazakh government is blocking Russia's use of this launch pad at Baikonur to fire a Soyuz rocket with a cargo supply craft for the Mir space station.