By Jerry Knight
Washington Post Staff Writer
Tuesday, November 17, 1998; Page A1

Before dawn this morning, in the basement of Intelsat headquarters in Northwest Washington, four people began sending messages to 25 satellites orbiting 22,000 miles above the equator.

One by one, they signaled the satellites that carry phone calls, transmit television programs, handle hotel and airline reservations, and transfer money from bank to bank: Warm up thrusters. Start gyros. Enable de-spin action nutation motors. Switch communications to high-power, wide-range. Set safety systems. Shut down all nonessential functions.

Prepare for meteor storm – the most intense barrage of meteorites hurtling toward Earth in 32 years.

In a two-day meteor storm that peaks this afternoon, thousands, perhaps tens of thousands, of tiny particles of space dust will rush past the planet as the Earth and the meteorites slip by each other at 200 times the speed of sound. The space junk is refuse flung out from the tail of the comet Temple-Tuttle, which circled past the sun in February.

None of the meteorites – most no larger than a grain of sand – will be big enough to shoot through the Earth's atmosphere without burning up. But while mankind seems safe, the meteors could be dangerous, perhaps fatal, to the 600 satellites and spacecraft orbiting the globe.

"The probability that a geosynchronous communication satellite will have a single hit is somewhere in the neighborhood of 1 in 500," said Stephen J. Stott, director of satellite engineering support and processes for Intelsat, the international consortium of government and private agencies that operates communications satellites from its Connecticut Avenue headquarters.

Because the Earth and its satellites spin around the sun in one direction – counterclockwise – and the meteorites are swooping in from the opposite direction, they could collide head-on at 44 miles per second, Stott explained. The danger is not that a satellite will take a rock in the windshield, but that an electrical spark caused when the particle hits could disrupt satellite electronics.

With 600 targets, the 1-in-500 odds mean it is quite likely that something will get hit. But whether the collision disrupts any of the vast number of businesses that depend on satellites will be determined by what gets hit and how well satellite operators have protected their fleet.

The attack was easily predicted by astronomers, who identified Temple-Tuttle's schedule almost two centuries ago. Its orbit is so precisely timed that the storm's peak is expected at 2:43 p.m., with the leading edge having moved in overnight.

In Asia – where the storm will peak in the middle of the night – the night sky will sparkle with thousands of tiny streaks an hour. Here, the meteorites will not be visible by day, but if skies are clear tonight, there should be something of a show near the constellation Leo, for which this meteor storm is named.

Only about 100 satellites were in orbit the last time this meteor storm swept the earth, in 1965. Since then, satellites have become essential to the world's commerce, communications and entertainment.

Some satellites are hunkering down to avoid the cosmic dust storm. The Hubble Space Telescope has been turned so its fragile lens faces away from the incoming debris. Some military spy satellites also have been temporarily shut off.

But the big communications satellites Intelsat operates carry so much vital information that they must be kept working.

Stott is confident that Intelsat's precautions will boost the odds of a damaging hit to more like 1 in 5,000. "In the most likely scenario, there will be some very minor traffic interruptions that may or may not be significant," he said. "We're not expecting to see a satellite fall out of the sky. In the worst-case scenario, one or two satellite operators may have five- or 10-minute outages."

Stott and the other scientists and engineers who manage satellite systems began more than a year ago to prepare their space fleets for the Leonid showers. By yesterday morning, the defense of the satellites was down to the final stages, spelled out in a methodical game plan.

When the peak of the storm hits this afternoon, operations manager Andy Lopatin and four veteran controllers will be at consoles sending signals to space, working with lead controller Nolan Adams, who was an air traffic controller at National Airport before joining Intelsat.

Directing satellites is "highly stressful work," Adams said. In the control tower at National, he explained, "you can see it coming, you see the traffic backing up, but here you never know."

Even with optical and electronic telescopes and radar trained on the meteorites, controllers won't know there's been a hit until warnings go off on two big computer screens.

Intelsat controllers tweaked each of the satellites yesterday, positioning them against a hit. Each satellite is almost as big as a minivan, bristling with antennas. Most of them sprout a pair of solar power panels, stretching out to a 90-foot wingspan.

The panels normally rotate, always automatically aimed at the sun to produce maximum power. But controllers yesterday signaled each satellite to stop turning its panels briefly, sacrificing power to put them in a less vulnerable position.

When the storm hits, the panels will point directly at the incoming meteorites. Instead of a target as big as a barn, the meteors will fly toward only the two-inch-thick edge of the solar arrays and the 10-foot-square body of the craft.

Satellites routinely are struck by stray meteorites, triggering static-electricity charges much like those felt by a person shuffling across a carpet on a dry winter day.

One model of Intelsat satellite fires its thruster rockets when it is hit by a surge of static, Stott said. Those thrusters will be shut off to avoid accidental misfiring.

On the rest of the fleet, the thrusters will be warmed up so they can be used to immediately nudge the satellite back into proper orbit if a meteorite knocks it astray. Controllers also will power up the de-spin action nutation motors, which stop the satellite from wobbling.

Intelsat's first warning of a Leonid problem may come from an experimental static-monitoring system developed by engineer Ahmet Ozkul.

Ozkul's monitors look like electrocardiograms as they display flashes measuring the static hitting the satellites. Yesterday, engineers knew they hadn't seen anything yet.

Ordinarily, the spikes reach 25 to 50 volts, but one monitor recently signaled 1,600 volts, the highest reading yet recorded. "We think that was the Leonids," Ozkul said.