Space shuttle Endeavour is on course to dock with the International Space Station at 12:17 p.m. EDT today, kicking off a busy eight-day stay to exchange resident crews, perform three spacewalks and deliver supplies and equipment.

Illustration of Endeavour docked to the International Space Station. Photo: NASA TV/Spaceflight Now

The terminal rendezvous phase will begin at 9:57 a.m. EDT with the shuttle trailing the station by about 9.2 statute miles. From there, Cockrell and Lockhart will oversee a series of computer-controlled rocket firings designed to place the shuttle at a point 600 feet or so directly below the space station.

At about that point, Cockrell will take over manual control and pilot Endeavour in a slow loop up to a point 300 to 400 feet directly in front of the lab complex as both spacecraft race through space at five miles per second.

"We're going to come underneath it," Cockrell said. "We just tell the autopilot to start tilting the tail towards the Earth and then we scoot it along so that, as it tilts toward the Earth, we end up in front of the space station. It's kind of quasi-magic, but it works.

"And then, while we're up here in front of the space station, the computer or the autopilot just holds the tail pointed straight at the Earth, and then we just guide it left, right, and in and out, down towards the station."

The station will be oriented with its long axis in the direction of travel. A pressurized mating adapter mounted on the forward end of the Destiny laboratory module will face Endeavour. Destiny, in turn, is attached to the U.S. Unity module, a multi-hatch gateway linking the lab to the rest of the station.

Directly across Unity from Destiny is a pressurized mating adapter leading into the Russian Zarya propulsion and cargo module. Zarya, in turn, is attached to the Russian Zvezda command module at the aft end of the station's long axis.

A Progress supply ship currently is docked to Zvezda's aft port while the on-board crew's Soyuz lifeboat is docked to a downward-facing port on the Russian-built, NASA-financed Zarya module. Another Russian docking port in a module attached to Zvezda is currently vacant.

Extending 90 feet up from the Unity module's zenith hatch is the Z1 truss and P6 solar array, which provides the bulk of the station's current power. The P6 array ultimately will be repositioned at the end of the station's main truss, the first element of which was installed during the most recent station assembly mission in April.

The station's Quest airlock module, which will be used for all three of the upcoming STS-111 spacewalks, is attached to Unity's right-side, or starboard, hatch.

Positioned directly in front of the station's long axis, Cockrell will manually guide Endeavour in so the docking system in the shuttle's cargo bay can mate with its counterpart on the pressurized mating adapter, or PMA. After hooks and latches engage, the two spacecraft will be locked together.

"It's really a fun piloting task," Cockrell said. "It's like driving a ship. You make very small inputs that take a long time to occur; but once they occur, they're very hard to stop. So it's something you need to do very precisely and it takes a lot of practice.

"So we go in very slowly and gradually, we slow down at about 30 feet away from the docking port and just look through a zoomed-in camera at the target. The target has a little set of alignment guides on it and we make sure that we're all lined up, that the two vehicles are exactly in plane.

"And then, from 30 feet in, we just hold a steady rate and we crash into the station," he joked. "That's a very slow crash. It's one-tenth of a foot per second. It's as slow as a snail would crawl."

After leak checks, hatches between the two spacecraft will be opened and station commander Yuri Onufrienko and his two Expedition 4 crewmates, Daniel Bursch and Carl Walz, will welcome the shuttle/Expedition 5 crews on board. After a safety briefing, the combined crews will get down to work.