ESA’s Lisa Pathfinder Mission Faces 2 Year Delay

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PARIS — Europe’s Lisa Pathfinder satellite is likely to be delayed until 2014, nearly two years later than its most-recent schedule, because of failures of two key elements during final testing, European Space Agency (ESA) officials said Feb. 3.

Program managers are expected to decide in mid-April whether to change the technologies used in the equipment or continue with their use. The new delay is likely to add up to 30 million euros ($41 million), which would bring the mission’s total budget, including launch and operations, to nearly 350 million euros.

Lisa Pathfinder is designed to test technologies for the much larger Lisa, or Laser Interferometry Space Antenna, mission that ESA and NASA are considering as a bilateral effort to launch around 2022 to measure gravitational waves from black holes and other astronomical sources.

The U.S. and European agencies had agreed that certain aspects of the Lisa mission were too challenging to be agreed to without a demonstration mission. Lisa Pathfinder is that mission.

The mission was budgeted at 185 million euros in 2006, a figure that rose to 227 million euros a year later.

One of the two components that failed in late 2010, a hydraulic launch lock that is part of the satellite’s Caging Mechanism Assembly, had caused problems earlier in tests. These glitches were later blamed on debris found in the launch lock’s hydraulic actuator.

The launch lock’s purpose is to keep Lisa Pathfinder’s sensitive test mass in place as the rocket climbs through the atmosphere and transmits vibrations to the satellite.

Giuseppe Racca, Lisa Pathfinder’s project manager at ESA, said his team will spend the next several weeks deciding whether to maintain the hydraulic actuator or replace it with a mechanical actuator.

The second issue that is delaying the program is its advanced Field Emission Electric Propulsion, or FEEP, micropropulsion system. During an early set of flight tests, the FEEP gear worked better than needed, Racca said in a Feb. 3 interview. But in a more recent set of tests, it demonstrated less-stable propulsion capability.

Program managers are now debating whether to stick with the FEEP technology or replace it with a tested U.S. system called the Colloid microthruster.

Racca said the 1,900-kilogram Lisa Pathfinder is scheduled for launch on the third flight of Europe’s new Vega small-satellite launcher. Vega’s inaugural flight has been delayed and is now not expected to occur before late this year.

One reason the nearly two-year delay will not cost more is that the Lisa Pathfinder satellite “is nearly completed,” Racca said. “It’s a shame these issues occurred so late in the program, but the satellite can be stored for a modest investment.”

NASA and ESA officials have said that if they decide to join forces on the larger Lisa mission, they would nonetheless not start full construction of the satellite before viewing the results of Lisa Pathfinder.