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How Inertia Saved LISA Pathfinder Mission

In this  ESA image, taken with an ultra-wide angle fisheye lens Nov. 19, the LISA Pathfinder spacecraft is hidden from view, encapsulated in the upper stage of its Vega rocket.

LONDON — Europe’s LISA Pathfinder fundamental-physics satellite was successfully launched Dec. 3 on a mission to help prove Einstein’s Theory of Relativity, but it has already demonstrated – once more – Newton’s law of inertia as applied to government programs.

The launch, from Europe’s Guiana Space Center on the northeast coast of South America, also marked the end of the long demonstration phase for Europe’s Vega small-satellite launcher, which has now posted six successes in six launch attempts.

The Italian-led Vega rocket has completed its European Space Agency-financed test phase, which included multiple missions to showcase Vega’s versatility.

The Arianespace launch consortium of Evry, France, purchased 10 Vega rockets from Avio SpA of Italy, which is Vega’s industrial prime contractor. Arianespace Chief Executive Stephane Israel said Arianespace has already sold nine of these vehicles.

Getting Avio to raise the production rate for Vega to be able to handle three launches per year was a major goal in bringing down Vega’s cost, and that was achieved with the three launches conducted in 2015, compared to one in 2014.

“Vega has fully proven itself,” ESA Launcher Director Gaele Winters said after the LISA Pathfinder flight. “There will now be a smooth transition to commercial use.” Vega is designed mainly for Earth observation, science and technology-demonstration satellites.

Vega lifted off Dec. 3 from French Guiana at 1:04 a.m. local time, placing LISA Pathfinder into an elliptical parking orbit (ESA photo)
Vega lifted off Dec. 3 from French Guiana at 1:04 a.m. local time, placing LISA Pathfinder into an elliptical parking orbit (ESA photo)

The 1,906-kilogram LISA Pathfinder was built by a 40-company team led by Airbus Defence and Space, and was budgeted at 180 million euros in 2006. By 2011, after it became clear that several necessary technologies were taking more time to perfect than expected, the budget was reassessed at 400 million euros, or about $440 million at today’s exchange rates.

With the technology hurdles so high and the budget so far out of its initial envelope, LISA Pathfinder was nearly canceled in 2011. The full Laser Interferometry Space Antenna mission of three satellites was put on hold, raising the question of whether the pathfinder satellite should be maintained.

It was a rare existential crisis at Europe’s Science Program Committee, which is loath to put the brakes on missions but in this case seriously considered doing so.

The pathfinder satellite was allowed to proceed in part because its drag-free-flight-control technology was deemed valuable enough for future missions, and in part because of the natural tendency of program managers to want to maintain momentum on a program they had spent years developing – especially because of the appeal of the first-order physics questions being addressed.

LISA Pathfinder is now expected to cost around 450 million euros from ESA’s budget, plus a substantial increment coming from the national science laboratories and space agencies providing their own contributions.

ESA officials hope that the mission can be conducted jointly with NASA with a launch in 20 years or so. The subject is one possible agenda item for ESA government ministers when they meet to set a multi-year space agenda in late 2016.

After removal from its transport container, LISA Pathfinder is transferred to a work dolly in a high bay at Guiana Space Centre in Korou (ESA photo).
After removal from its transport container, LISA Pathfinder is transferred to a work dolly in a high bay at Guiana Space Centre in Korou (ESA photo).

“LISA Pathfinder is only a step – a major step, surely, but only a step – toward a much more ambitious goal of a gravitational wave mission,” ESA Science Director Alvaro Gimenez said after the launch. “That mission is now closer than ever and we will fly it sooner rather than later.”

ESA Director-General Johann-Dietrich Woerner, in remarks made before the LISA Pathfinder launch, was more cautious: “I hope we will have LISA in the near future,” he said, referring to the Laser Interferometry Space Antenna, which had been intended as the full gravity-wave mission.

NASA’s contribution to LISA Pathfinder was the experimental Disturbance Reduction System to demonstrate the ability of a solid body to float in space undisturbed – a key component to any full gravity wave detection mission.

LISA Pathfinder’s propulsion unit will gradually raise the satellite’s orbit. It is expected to reach its operating position, the Lagrangian Point 1 (L1) some 1.5 million kilometers from Earth, in mid-February and to operate for one year.

SpaceNews.com

Source: Space News

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How Inertia Saved LISA Pathfinder Mission

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