Ariane 5 Sends ATV-2 on its Way to the Space Station

by

PARIS — Europe’s ATV-2 unmanned space freighter on Feb. 15 was successfully placed into orbit aboard an Ariane 5 ES rocket and is expected to dock at the international space station Feb. 23 to deliver fuel and other cargo, and to reboost the station into a higher orbit.

During its nearly four-month stay, ATV-2 will also be used, as needed, to maneuver the station’s orbit higher or lower to avoid debris, saving the station’s on-board fuel for use after ATV-2 leaves.

ATV-2, named Johannes Kepler, will remain attached to the station until June under current planning, when it will be loaded with garbage and destroyed on re-entry into the Earth’s atmosphere over an uninhabited stretch of the South Pacific.

The launch, from Europe’s Guiana Space Center in French Guiana, was the first of a planned six Ariane 5 liftoffs for 2011. At just over 20,000 kilograms, ATV-2 is the heaviest payload ever launched by an Ariane rocket. The Ariane 5 ES version lists its maximum payload into the ATV’s 260-kilometer orbit at 20,050 kilograms. ATV-2 at launch weighed in at about 40 kilograms less than that.

It was a launch whose delay from late 2010 had irked Europe’s biggest space station backer, the German government, which openly speculated whether the ATV-2 liftoff was bumped in favor of telecommunications satellites solely to help the commercial fortunes of Europe’s French-led Arianespace commercial launch consortium.

The ATV program was developed by the 18-nation European Space Agency (ESA) as a way to pay its station-operations debt to NASA with in-kind contributions rather than in cash.

ATV-2 mission costs are estimated at 450 million euros ($612 million) in 2011 inflation-adjusted euros, according to Hans Peter Leiseifer, head of ATV engineering at ESA. The figure includes 150 million euros for the Ariane 5 launch; 220 million euros for the ATV-2 vehicle, built by a contracting team led by Astrium Space Transportation of Bremen, Germany, and Thales Alenia Space of Turin, Italy; and 70 million euros in operating costs over the four-month mission, Leiseifer told reporters during a Feb. 9 briefing.

Kris Capelle, ATV-2 mission director, said the exact date of ATV-2’s departure will depend in part on the schedule of the U.S. space shuttle, notably the number of shuttles that will dock with the station between now and when the ATV-2 must depart the orbiting facility in late August. The ATV’s maximum stay time at the station is six months. Currently NASA has two missions remaining on the manifest before the fleet is retired this year, the first of which is slated to launch Feb. 24, but the U.S. Congress has directed that NASA fly at least one more mission.

“We will wait to de-dock [ATV-2] a little later if there is a chance of a second shuttle arriving” before the European craft must depart, Capelle told the Feb. 9 briefing. “The shuttle docks to the station at an altitude of 350 kilometers, and we reboost the station to an altitude of 375-380 kilometers.”

Residual atmosphere at the station’s altitude pulls the outpost toward Earth at a rate of several 10s of meters per day. Raising it as high as possible is the goal of ATV-2, but because of the shuttle’s docking-altitude limits the maximum ATV reboost can be achieved only if there are no immediate plans for a shuttle arrival after the ATV’s departure.

The next space shuttle is tentatively scheduled to arrive at the space station Feb. 26, three days after ATV-2. The shuttle docks to the U.S.-built portion of the station, while ATV-2, which uses Russian docking technology, arrives at the Russian end of the orbital complex. For the shuttle docking to occur, Japan’s H-TV cargo carrier, which is similar to ATV but smaller, will need to be moved from its current locale to assure enough space for the shuttle’s cargo bay.

In mid-March, the three-person Russian Soyuz capsule now at the station is scheduled to return to Earth, and on April 1 a fresh Soyuz is scheduled to arrive.

As recently as a year ago, ESA officials had hoped to use the expertise gained with the ATV series to develop an ATV capable of returning cargo to Earth. In addition to adding value to the ATV missions in an era after the U.S. space shuttle’s retirement, the Advanced Reentry Vehicle would take Europe further down the road toward an autonomous astronaut-carrying capability.

The German government had been particularly keen on the idea, but has since abandoned it in the face of demands from France and other ESA governments that the total station-related operating budget through 2020 be kept to a minimum.

ESA governments, which have yet to formally approve the extension of the station’s operating life to at least 2020, are scheduled to meet March 17-18 in Paris to give their endorsement and to agree on how much they will spend on the station in the next decade.

 

RELATED ARTICLES

Station Partners Approve Delayed Launch of ATV-2 

ESA Re-entry Vehicle Tied to Station Extension