CAPE CANAVERAL, Fla. How do you park a $2 billion spaceship the size of a DC 9 at a seven-story space station while both are circling the planet at 25 times the speed of sound?

Very carefully.

And as incongruous as it might sound, very, very slowly.

But both also say that bringing two such massive craft together some 220 miles (354 kilometers) above Earth is not exactly like pulling the family minivan into a parking space at the neighborhood grocery store.

"We know how to do it, but docking should never be considered a piece of cake," Halsell said in an interview with SPACE.com, especially during the final tense moments before the ships lock in a metallic embrace.

"Well be closing at 0.1 feet (3 centimeters) per second which sounds really slow but when you have two huge masses heading for each other, its pretty exciting," Horowitz added.

Almost a year after NASAs last trip to the station, Halsell and his crew are scheduled to climb aboard shuttle Atlantis and take off May 18 on an outpost-maintenance mission.

The shuttles rendezvous and docking with the station will actually begin with the launch. These are precisely timed to put the ship on a direct course to the outpost during a thundering 8.5-minute climb above the shroud of Earths atmosphere.

A two-day game of catch-up will follow as Halsell and Horowitz perform a series of periodic engine firings to gradually bring Atlantis to a point 8 nautical miles (12.8 kilometers) behind the station.

Thats when the real action begins.

"This is sort of like the pivotal point of the rendezvous," Horowitz said. "At this point, things start getting really busy."

A long burst from the shuttle jet thrusters will enable the crew to close the final gap between Atlantis and the station in relatively fast fashion 90 minutes or one spin around the planet.

All the while, the shuttles flight deck will be bustling with activity.

With Halsell watching over the controls, Horowitz will be keeping track of a step-by-step rendezvous and docking checklist so that the skipper can concentrate on the initial autopilot portion of the docking.

In the shuttle cockpit window, the docking module is visible, as the astronaut maneuvers the shuttle towards the station.

Flight engineer Jeff Williams will keep a constant eye on cockpit gauges and instrumentation to make sure all shuttle systems are performing as expected. Mission specialist Mary Ellen Weber will check out the shuttles docking ring to make certain it will latch properly with an identical device on the station.

Floating in front of a laptop computer, crew mate Susan Helms will call out information on the shuttles range to the station, as well as its closing rate, and astronaut Jim Voss will be armed with still and video cameras to document the event as it unfolds.

Meanwhile, Russian cosmonaut Yuri Usachev will act as the cockpit traffic cop.

"Ill have Yuri on the flight deck next to me with a hand-held laser; not unlike what might be used by a police officer, except its using laser energy, not radar energy, to shoot the International Space Station," Halsell said.

Laser beams bouncing back off the station give the crew a second, backup source of range and closing rate data in case problems crop up with cargo-bay lasers feeding information to the laptop computer being operated by Helms.

A view of the ISS as the sun creeps over the surface of the earth.

The real precision piloting will begin when Atlantis closes to within 2,000 feet (606 meters) of the station. At that point, Halsell will move from his cockpit seat to a flight station at the rear of the shuttles crew cabin. Then, peering out the ships back windows, the Air Force colonel will take manual control of the ship during the final, torturously slow phase of docking.

Flying along at three feet (90 centimeters) per second, Halsell first will ease the shuttle to a point 1,000 feet (303 meters) from the outpost as ground controllers "feather" the stations power-producing solar arrays so their edges face Atlantis.

Doing so will help prevent the fragile solar wings from being flexed, over-stressed or contaminated by the force -- and toxic exhaust created during shuttle thruster firings.

And as the shuttles slow creep continues, Halsell will only fire jets offset from the station to avoid damaging the arrays, which provide electrical power to run all outpost systems.

The barnstorming part of the rendezvous will come after Halsell nudges Atlantis to a point 600 feet (182 meters) directly below the station. In what amounts to a barrel roll in space, the veteran commander will fly Atlantis around to a point 350 feet (106 meters) above the station to align the shuttle with its outpost docking port.

Then, flying the shuttle tail-first and upside down, Halsell will gently ease Atlantis down to its docking port at the glacial pace that slows from a half-foot (15 centimeters) to a single inch (2.5 centimeters) per second.

All this must be done within minutes as Atlantis and the outpost pass over a Russian ground station. And Halsell must hit his target within a mere 3 inches (7.6 centimeters) in order for 96 latches on both the shuttle and station docking rings to snap shut a must for an airtight seal between the craft.

Its been done before, and it will have to be done over and over again during 15 years of station construction and operations. But some astronauts say the inherent difficulty of a shuttle docking at the station is largely lost on the general public.

"I dont know if most people realize how complex an effort this is," said Weber.

"I mean, we have two vehicles that are going at over 17,000 m.p.h. (27,350 kilometers per hour), both on slightly different paths, and we need to bring them together and dock them at a rate thats about a 10th of a foot per second," she said. "So its an incredibly complicated thing."

Like most self-assured pilots, though, Halsell who has been training more than a year in simulators to do the job expects the high-flying hookup to come off without a hitch.

"Weve practiced it many times," he said, "so I feel confident that well do great."