by Staff Writers
Paris (ESA) Jan 25, 2016
After a six-week journey, LISA Pathfinder arrived at its destination today, an orbit around a point of balance in space where it will soon start testing technologies crucial for exploring the gravitational Universe.
LISA Pathfinder is testing the key elements that could be used for a future mission to detect gravitational waves - ripples in spacetime predicted by Albert Einstein in his General Theory of Relativity. To this end, it will release two test masses into near-perfect free fall and measure their motion with unprecedented accuracy.
LISA Pathfinder was launched on 3 December 2015 and arrived today in its orbit around 'L1', the first libration point of the Sun-Earth system, a virtual point in space some 1.5 million km from Earth towards the Sun.
LISA Pathfinder's arrival came after a final thruster burn using the spacecraft's hard-working propulsion module on 20 January. The small, 64-second firing was designed to slightly change its speed and just barely tip the craft onto its new orbit about L1.
Since launch, the propulsion module raised the orbit around Earth six times, the last of which kicked it towards L1.
"We had planned two burns to get us into final orbit at L1, but only one was needed," says Ian Harrison, Spacecraft Operations Manager at ESA's ESOC operations centre in Darmstadt, Germany.
Separation after arrival 1.5 million km away
"Heat and vibration from the regular, hot thrusters on the propulsion module would cause too much disturbance during the spacecraft's delicate technology demonstration mission," notes Ian. "Primary propulsion during the rest of the mission will be provided by cold-gas microthrusters to keep us at L1."
These small thrusters were used in the hours after separation to kill the spin and stabilise the spacecraft.
Big ears provide global coverage
During this evening, the craft will be slowly turned to point towards Earth and, around midnight, establish a full communications link via ESA's New Norcia ground station, Australia.
Next week, LISA Pathfinder's trajectory will be fine-tuned with a series of three microthruster bursts, taking it onto its final orbit, a 500 000 + 800 000 km orbit around L1.
L1 was chosen because it is a quiet place in space, far away from large bodies such as Earth and is ideal for communications.
Preparing to test future technology
Last week, the laser that will measure the most precise free-fall ever obtained in space was switched on and tested.
Next month, the two identical test cubes will be released in two steps. First, the launch lock fingers on the eight corners of each cube will be retracted on 3 February. Then, other mechanisms that secure the cubes will be released on 15 and 16 February.
This will enable the craft to begin, on 1 March, demonstrating that we can measure the separation of target masses with the extremely high accuracy required to measure gravitational waves from space in the future.
The relative motion of the two cubes will be measured by laser to within a staggering a billionth of a millimetre.
LISA Pathfinder at ESA
The Physics of Time and Space
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|