Europe's second Automated Transfer Vehicle firmly docked to the International Space Station Thursday, delivering fresh equipment, rocket fuel and oxygen to the orbiting lab hours before space shuttle Discovery was scheduled to blast off with even more supplies.

Credit: ESA

Named for Johannes Kepler, the German astronomer and mathematician, the ATV arrived at the aft port of the station's Zvezda service module at 1559 GMT (10:59 a.m. EST) after a multi-hour rendezvous sequence.

"With this smooth docking, Johannes Kepler proves to be a great example of the wave of innovation 'made in Europe,'" said Simonetta Di Pippo, head of the European Space Agency's human spaceflight program. "We are more ready than ever to head into an era of autonomy in space exploration."

Docking occurred as the vehicles flew near the coast of Liberia in western Africa.

Navigating with relative GPS satellite technology and a futuristic laser system, Johannes Kepler approached the space station Thursday morning, stopping occasionally at preset hold points for engineers on the ground to evaluate the mission's progress.

The spacecraft appeared from darkness during a dramatic orbital sunrise, looming large with flashing lights just behind the space station. Resembling a Star Wars X-wing fighter, Johannes Kepler glided to a smooth docking about 10 minutes later than planned.

The space station crew reconfigured a video overlay computer inside the Zvezda module to allow them to better monitor the ATV's approach, resulting in the brief delay.

Hooks and latches engaged a few minutes later to firmly attach the Johannes Kepler spacecraft to the station, clearing the way for the shuttle Discovery to blast off Thursday at 2150 GMT (4:50 p.m. EST).

Discovery's dark orange external tank was already filled with more than 500,000 gallons of liquid hydrogen and liquid oxygen propellants at the time of the ATV's docking, but NASA was withholding final approval for the shuttle launch until the European mission safely arrived.

Space station managers didn't want the ATV docking while Discovery is also at the outpost, but the successful arrival Thursday means there will be no such conflict.

Officials worldwide have been carefully managing hectic schedules aboard the space station in recent weeks. Besides the ATV and the space shuttle, Japan's H-2 Transfer Vehicle is delivering cargo to the complex. Smaller Russian Progress freighters have also been coming and going.

The space station crew will open up the 31-inch-wide passageway between the ATV and Zvezda Friday, beginning several months of cargo transfers between the supply ship and the orbiting lab.

The second of at least five European Space Agency cargo ships, Johannes Kepler blasted off Feb. 16 aboard an Ariane 5 rocket from the Guiana Space Center on the northeastern coast of South America. The spacecraft traveled over eight days and 2.5 million miles to catch up with the space station.

Artist's concept of the ATV's laser rendezvous sensor system. Credit: ESA

ESA developed the ATV to help pay its share of the space station's operating costs. Each mission costs about $600 million, according to European officials.

The Automated Transfer Vehicle will be the largest resupply ship for the space station after the shuttle fleet is retired.

"This is very important for us and for all our partners in the ISS program since, after the withdrawal of the space shuttle, ATV will be the largest servicing vehicle left to support the Station and it is our responsibility to deliver a proper service," Di Pippo said.

Europe is weighing modifying the ATV to return experiments and other cargo from the space station to Earth.

"Thanks to its flexibility, we can think of a wide variety of new space vehicles," Di Pippo said. "ATV could evolve into a future reentry spacecraft to support future orbital infrastructures and exploration missions, carrying people and supplies to lunar orbit."

Built by Astrium, the ATV measures 32 feet long and nearly 15 feet wide. Its four solar array wings stretch more than 70 feet across. Four main engines and 20 smaller thrusters guide spacecraft in orbit.

"The ATV is a tangible proof of the technologically sophisticated space systems that Astrium, as a truly European company, can provide," said Alain Charmeau, CEO of Astrium space transportation. "Our teams in Germany and France worked together in perfect harmony, supported by superb suppliers all around the continent. We are very proud that the fully-automatic docking procedure -- the highlight of the mission -- passed off without a hitch."

The Johannes Kepler mission carries about 3,500 pounds of dry cargo in its pressurized cabin to be manually unloaded by the astronauts and cosmonauts aboard the space station. The pressurized supplies include about 1,400 pounds of crew equipment, 1,300 pounds of hardware components and spare parts, 210 pounds of experiment parts, 100 pounds of laptop computers and related supplies, and 60 pounds of spacewalk gear, according to NASA.

About 1,875 pounds of maneuvering propellant and 220 pounds of breathing oxygen will be transferred through plumbing from the ATV to the Russian segment of the complex.

The ATV's thrusters will burn more than 10,000 pounds of its own fuel to maintain the station's orientation in space and boost the lab's orbit by up to 40 kilometers, or about 25 miles, later this spring.

Johannes Kepler is currently scheduled to depart the space station June 4 and plummet back into Earth's atmosphere with a load of trash and refuse. The spaceship and its new cargo of garbage will burn up over the Pacific Ocean.