Maiden launch of Europe's resupply ship gets new date
BY STEPHEN CLARK
Posted: February 10, 2008
Europe's first Automated Transfer Vehicle, an intricate 43,000-pound resupply ship, will have to wait two more weeks to begin its voyage to the international space station after managers ordered a delay to add a "final level of robustness" to the crucial mission, officials said last week.
The ATV has been grounded at its South American launch site since its arrival at the base last summer. After months of assembly, fueling, problem-solving, and packing, the satellite is almost ready to go, said Alan Thirkettle, the European Space Agency's international space station program manager.
Senior agency leaders met last Wednesday to formally approve a 15-day delay in the mission, which is now scheduled for a March 8 blastoff from Kourou, French Guiana. The first ATV, named Jules Verne, will ride into space at the point of a beefed up Ariane 5 rocket.
Liftoff is set for 0424:47 GMT (11:24:47 p.m. EST March 7) during an instantaneous launch window.
Officials opted to postpone the mission to pace themselves before committing the ATV to launch, Thirkettle said.
"It's a matter of prudence," he said.
ESA did not purchase insurance for the $1.9 billion mission, but they instead designed the ATV with several levels of redundancy and conducted additional testing to offset the risk, according to Thirkettle.
Conceivably, the cargo-laden craft could have still launched this month. The ATV was ready for the move to the final assembly building to be attached to the top of its Ariane 5 booster early this week. The rocket will be prepared to receive its payload by the middle the week, Thirkettle said.
But that would have required an army of engineers and technicians to work long hours and weekends.
Control teams in Europe also strongly recommended completing more mission simulations to ensure they were ready to support the flight, which is hailed as the most complex ever attempted by ESA.
"You give a ground segment three weeks and that's three more weeks of simulations," Thirkettle said.
The ATV's mission has been first in line for Arianespace since late last year, but it has been hit with more than a month's worth of delays since then.
The setbacks should not impact the company's busy commercial manifest for the rest of the year, which includes seven Ariane 5 launches, said Aaron Lewis, Arianespace spokesperson.
"Last year, at one point, we demonstrated our ability to launch eight payloads in five months," Lewis said. "Likewise, this year, we don't anticipate any problems in managing our manifest."
Launching on March 8 would push back the ship's arrival at the space station from mid-March until at least March 30. The ATV would have until April 5 to pull into port at the rear end of the station's Zvezda service module, based on strict sun angle requirements and station traffic.
Engineers have established rigid solar angle restrictions because the sun's glare could interfere with the ATV's suite of optical rendezvous sensors, which are needed to approach the station at close distances.
Officials must also consider visiting space shuttles, Soyuz capsules and Progress vehicles. The ATV cannot dock to the station when a shuttle is present or when Russian vehicles are arriving or departing.
The timeline calls for the ATV to launch March 8 and gradually raise its orbit to the altitude of the space station during the next 10 days during space shuttle Endeavour's scheduled visit.
European controllers expect to begin two days of critical demonstrations after the shuttle undocks from the station, currently set for about March 23. If those tests go as planned, the ATV could dock by the end of March, Thirkettle said.
ESA officials are eager for the ATV to get to the station before Soyuz and space shuttle missions in April.
"If we move too late, we would have problems docking with the space station," Thirkettle said.
The ATV carries enough propellant to loiter in a parking orbit for up to several months to wait out a flurry of visiting spacecraft, but managers don't expect it to come to that.
"We're actually more flexible in space than we are on the ground," Thirkettle said.