Ariane 5 Launches Final ATV Mission to Station
KOUROU, French Guiana — Europe’s Ariane 5 heavy-lift rocket on July 29 successfully launched the fifth and final Automated Transfer Vehicle (ATV) cargo carrier toward the international space station, marking the beginning of the end for a program whose most important legacy may be a U.S.-European partnership of mutual dependence in manned spaceflight.
Weighing 20,300 kilograms — including adaptors in addition to the vehicle itself — ATV-5 was placed into a 260-kilometer orbit and was reported in good health by its ground managers at the European Space Agency. The vehicle is carrying some 7,000 kilograms of fuel, water, food and other supplies.
Director General Jean-Jacques Dordain announced shortly after the launch that ATV-5’s solar panels had been deployed successfully.
It is scheduled to dock automatically to the space station Aug. 12, where it will stay for about six months before being loaded with garbage and sent on a destructive re-entry into Earth’s atmosphere over the South Pacific.
ATV-5 has two mission elements that set it apart from its four predecessors, which were launched between March 2008 and June 2013.
The first uses a radar and three visible- and infrared-spectrum cameras to examine the station in a “fly under” maneuver before docking. During the maneuver, the ATV will approach to within 3.5 kilometers of the station to image it in ways that ground teams hope will be useful for future space surveillance and rendezvous activities with “non-cooperative targets” and orbital debris removal attempts.
The second element comes into play during ATV-5’s descent into the atmosphere over the South Pacific. The four preceding ATVs were guided into a steep dive into the atmosphere to minimize the area in which any debris that survived re-entry fell into the ocean.
At NASA’s request, ESA decided to have ATV-5 enter the atmosphere at a much shallower angle, spending more time in the upper atmosphere to simulate the behavior of the space station when the time comes to retire it.
The station weighs some 420,000 kilograms, is composed of multiple modules and has a vast field of solar arrays, but similarities between the basic configuration of the two vehicles make it useful to see how ATV-5 breaks up over a longer flight through the atmosphere.
NASA, which is the station’s general contractor, wants to continue operating the space station until 2024 and is waiting for the other space station partners — Russia, Japan, Europe and Canada — to signal their intentions. Currently the other partners are committed only until 2020.
The end of the ATV program deprives the station partners of the only vehicle that, by itself, could deorbit the space station. Current planning is to use two or three Russian Progress vehicles for the job.
ESA officials said their agency is set up to perform research and development and not to build identical copies of the same hardware. In the meantime, NASA had contracted with Space Exploration Technologies Corp. of Hawthorne, California, and Orbital Sciences Corp. of Dulles, Virginia, to deliver freight to the station.
Japan’s HTV freighter continues in operation, leaving four vehicles to handle station resupply — enough to meet the requirements.
The ATV has been used by ESA to pay its 8 percent share of the station’s common operating costs. At the end of the ATV-5 mission, ESA will have paid NASA the European share of operations through 2017.
For the remaining three years — or perhaps longer — ESA has agreed to use many ATV technologies to provide NASA with the service module for the U.S. agency’s Orion Multi-Purpose Crew Vehicle.
The current agreement carries ESA’s role only through the construction and delivery of a first Orion service module and provision of components for a second service module. NASA retains the intellectual property to the ESA work and could assign a U.S. contractor to do it if the ESA-NASA cooperation accord does not continue.
But NASA and ESA officials have said the goal is that ESA will remain on the “critical path” for NASA’s human spaceflight program by continuing to provide the service module.
ESA’s most immediate space station goal is to secure its member governments’ commitment of some 205 million euros ($279 million) needed to complete the current Orion service module work.
Many in Europe regret that ATV is being retired so early, but ESA officials said the cost of delivering a kilogram to orbit aboard ATV was too high to continue the program.
William H. Gerstenmaier, NASA associate administrator for human exploration and operations, said July 29 that while ATV is a formidable vehicle, the station partners have taken steps to compensate for its retirement.
The station’s onboard fuel reservoirs have been filled, Gerstenmaier said. In addition, the orbital complex flies at a higher orbit than it did during the years when it was being assembled. Station controllers have also learned to save fuel by maneuvering the solar arrays to reduce atmospheric drag.
NASA has also learned to maneuver the station without fuel, which costs some $10,000 per pound to deliver to orbit. The Zero-Propellant Maneuver uses the small control momentum gyroscopes on board to make small adjustments.