A European cargo ship the size of a double-decker bus is primed for its maiden flight to haul fresh supplies toward the international space station.
Jules Verne, a massive unmanned cargo ship built for the European Space Agency is set to launch from the Guiana Space Center in Kourou, French Guiana. A modified European Ariane 5 rocket will loft the nearly 21-ton Jules Verne into orbit from its equatorial launch site on the northern coast of South America at 1:03 a.m. Kourou time Sunday (11:03 p.m. ET Saturday).
"It's the biggest spacecraft we've built in Europe and by far the most complicated," said John Ellwood, ATV mission manager for the ESA.
Jules Verne is the first of a new fleet of unmanned spacecraft, called Automated Transfer Vehicles (ATVs), to launch fresh supplies to station crews through at least 2015. The 32-foot (10-meter) long cylinder with a diameter of about 14.7 feet (4.5 meters) and a roomy cargo hold for food, clothes, new equipment and rocket fuel for the space station.
It is the first new spacecraft in nine years to join the flotilla of U.S space shuttles, Russia's manned Soyuz and unmanned Progress spacecraft that make station-bound flights, NASA officials have said.
"The ATV, as a logistics vehicle, carries almost three times the hardware, fuel, water and oxygen that a Russian Progress carries," said NASA's space station program manager Mike Suffredini. "It is a major contribution to the program."
For its inaugural flight, Jules Verne is packed with propellant and equipment for the station's three-astronaut crew, though ATVs are designed to haul up to 10 tons of supplies to orbit, according to ESA officials. The launch was delayed from a planned late Friday EST liftoff to late Saturday to double check work on its spacecraft separation system.
Jules Verne is due to spend about a week chasing the space station after launch, then park about 1,243 miles (2,000 kilometers) from the station to await the departure of NASA's shuttle Endeavour before proceeding with rendezvous demonstrations. The U.S. space shuttle is scheduled to launch March 11 on a 16-day construction flight to deliver a Japanese-built room and Canadian robot to the space station.
A European first
Built by France's EADS-Astrium, Jules Verne and its fellow ATV spacecraft are Europe's first spacecraft to launch and rendezvous with a crewed orbital outpost. ESA partner nations have spent $1.9 billion (1.3 billion euros) developing the spacecraft as part of a barter system to send future European astronauts and experiments to the space station.
"It's an extremely exciting vehicle for us," said ESA station program manager Alan Thirkettle, adding that the spacecraft has been under development since 1998. "It contains a number of new technologies."
Chief among those new technologies is the ATV's videometers, a visual-based navigation system that relies on lasers to home in on the space station.
Jules Verne and other ATVs will use a global positioning satellite (GPS) system to maneuver within about 816 feet (249 meters) of an aft docking port on the station's Russian-built Zvezda service module, then activate the videometer to beam laser pulses at a set of reflectors near the berth. By analyzing the light patterns reflected back, the videometer should be able determine precisely how far the ATV is from its docking port.
The spacecraft is also equipped with a secondary, radar-like sensor — called a telegoniometer — to monitor its position, mission managers said.
During two demonstration days, as well as the final docking, ESA flight controllers at the agency's new ATV control center in Toulouse, France, will put Jules Verne through its paces and test vital collision avoidance maneuvers to ensure the spacecraft won't crash into the space station should its rendezvous attempt go foul.
Unlike Russia's unmanned Progress ships, which can be remotely guided in by astronauts from a console inside the station, Jules Verne and other ATVs are fully autonomous.
"They cannot drive us in like they can a Russian Progress," Ellwood said. "All they can do is essentially press a red button if they feel we're being unsafe, and send us away."
Expedition 16 flight engineer Yuri Malenchenko, a Russian cosmonaut, and commander Peggy Whitson of NASA are the prime ATV controllers for Jules Verne's flight. Malenchenko performed the first-ever remote controlled docking of an unmanned Progress cargo ship from inside Russia's Mir Space Station in 1994.
"We're absolutely confident with the safety aspects of this spaceflight," Suffredini said.
Ellwood added that each ATV is also equipped with a complete backup system to take control of the spacecraft should its primary systems fail.
"We really have two spacecraft in the middle of this very great bird," Ellwood said.
Thirkettle said ESA plans to launch five ATVs to the space station by 2015 in order to secure a six-month slot aboard the space station for a European astronaut every other year. Astronauts recently delivered Europe's other major contribution, the Columbus laboratory module, to the station last month.
The interior of each ATV can be loaded with up to eight racks worth of equipment for astronauts to retrieve once the spacecraft reaches the space station. They are also designed to use their rocket engines to boost the station into a higher orbit and transfer new fuel into tanks inside outpost's Russian-built thrusters.
Each unmanned cargo ship is designed to stay docked at the station for about six months, then be filled with trash and other unneeded items for disposal in the Earth's atmosphere.
"We're now really feeling that Europe is really coming to the space station," Ellwood said.