LISA Pathfinder takes major step in hunt for gravitational waves

Nov 15, 2011
LISA Pathfinder about to enter the space environment vacuum test. Credits: Astrium UK

(PhysOrg.com) -- Sensors destined for ESA’s LISA Pathfinder mission in 2014 have far exceeded expectations, paving the way for a mission to detect one of the most elusive forces permeating through space – gravitational waves.

The Optical Metrology Subsystem underwent its first full tests under space-like temperature and vacuum conditions using an almost complete version of the spacecraft.

The results exceeded the precision required to detect the enigmatic ripples in the fabric of space and time predicted by Albert Einstein – and did it by two to three times.

In space, LISA Pathfinder will measure the distance between two free-floating gold–platinum cubes using lasers. In the ground tests currently being performed by the team in Ottobrunn, Germany, these cubes are replaced by separate mirrors.

In addition to measuring the distance between the cubes, it also measures their angles with respect to the laser beams – and the tests show an accuracy of 10 billionths of a degree.  

“This is equivalent to the angle subtended by an astronaut’s footprint on the Moon!” notes Paul McNamara, Project Scientist for the LISA Pathfinder mission.

Under perfect conditions in space, the free-floating cubes would be expected to exactly copy each other’s motions.

LISA Pathfinder with scientists in the clean room test environment. Credits: Astrium UK

However, according to Einstein’s general theory of relativity, if a gravitational wave were to pass through space, possibly caused by an event as catastrophic as the collision of two black holes, then a minuscule distortion in the fabric of space itself would be detectable.

The accuracy required to detect such a subtle change is phenomenal: around a hundredth the size of an atom – a picometre

The requirement set for the instrument was around 6 picometres, measured over 1000 seconds, which the team initially bettered in 2010.

During the latest testing, a staggering 2 picometre accuracy was obtained, far exceeding the best performance for an instrument of this type.

“The whole team has worked extremely hard to make this measurement possible,” said Dr McNamara.

“When LISA Pathfinder is launched and we're in the quiet environment of space some 1.5 million km from Earth, we expect that performance will be even better.”

The instrument team from Astrium GmbH, the Albert Einstein Institute and ESA are testing the Optical Metrology Subsystem during LISA Pathfinder thermal vacuum tests in Ottobrunn by spacecraft prime contractor Astrium (UK) Ltd.

LISA Pathfinder is expected to be launched in mid-2014 to demonstrate the technologies and endurance in space for a New Gravitational wave Observatory mission, one of the candidates for ESA’s next flagship mission, planned for a launch early in the next decade, aiming to find this final piece in Einstein’s cosmic puzzle.

Explore further: DNA survives critical entry into Earth's atmosphere

add to favorites email to friend print save as pdf

Related Stories

Measuring the universe

Aug 25, 2010

A unique antenna which could help unveil a new window on the universe by observing thousands of gravitational waves should be one of NASA's next space missions according to a group of leading US experts.

Better hearing with spaced-apart ears

Jun 02, 2011

(PhysOrg.com) -- Detectors in the US, Germany and Italy are lying in wait to gather evidence that would unveil one of Albert Einstein’s last secrets: gravitational waves. Up to now, it has not been possible ...

Searching for gravitational waves

Aug 09, 2011

Colliding neutron stars and black holes, supernova events, rotating neutron stars and other cataclysmic cosmic events… Einstein predicted they would all have something in common – oscillations in ...

Recommended for you

Rosetta's comet: In the shadow of the coma

4 hours ago

This NAVCAM mosaic comprises four individual images taken on 20 November from a distance of 30.8 km from the centre of Comet 67P/C-G. The image resolution is 2.6 m/pixel, so each original 1024 x 1024 pixel ...

DNA survives critical entry into Earth's atmosphere

Nov 26, 2014

The genetic material DNA can survive a flight through space and re-entry into the earth's atmosphere—and still pass on genetic information. A team of scientists from UZH obtained these astonishing results ...

Team develops cognitive test battery for spaceflight

Nov 26, 2014

Space is one of the most demanding and unforgiving environments. Human exploration of space requires astronauts to maintain consistently high levels of cognitive performance to ensure mission safety and success, and prevent ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.