Issue #1(19) 2019 Science

LISA Pathfinder – paving the way for future studies of the gravitational universe

Simulation of two merging black holes where the colours represent quantities related to the gravitational waves emitted from the system. LISA Pathfinder is paving the way for the detection of gravitational waves from space.
Simulation of two merging black holes where the colours represent quantities related to the gravitational waves emitted from the system. LISA Pathfinder is paving the way for the detection of gravitational waves from space.
Andreas Rudolph ESA/ESOC, Darmstadt, Germany

LISA Pathfinder was a pioneering ESA technology demonstration mission with a European and NASA payload. Launched in December 2015, its aim was to put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy, testing the technology needed to develop future spaceborne gravitational wave detectors. LISA Pathfinder is paving the way for ESA’s Laser Interferometer Space Antenna (LISA), the first gravitational wave observatory in space, planned for launch in the 2030s. Here, Andreas Rudolph presents an overview of the successful and highly unusual mission and looks ahead to LISA.

Gravitational waves are ripples in the curvature of space-time produced by accelerations of massive celestial bodies such as orbiting pairs of black holes, compact binaries or other astrophysical objects. Albert Einstein postulated the existence of gravitational waves from his theory of general relativity (1915). Ground-based detectors can only measure the high frequency band of gravitational waves. A first direct detection on ground took place in September 2015, leading to the award of the Nobel Prize in physics in 2017 (Weiss, Barish & Thorne).

However, to observe lower frequency gravitational waves in the range from 10-4 to 10-1 Hz a space-based detector, undisturbed by ground motion, is required. The principle of such an observatory is that free-falling test masses, which are isolated from all external forces, will move along geodesics of the curved space-time. If a gravitational wave travels in the neighbourhood of these test masses then a tidal effect will occur and this will result in a change in distance between the two test masses. The variation in distance is only in the order of pico-metres (10-12 m) over a million kilometres but it can be measured with a high-resolution laser interferometer.

To continue reading this premium article, subscribe now for unlimited access to all online content

If you already have a login and password to access www.room.eu.com - Please log in to be able to read all the articles of the site.

Popular articles

See also

Astronautics

Turning the Solar System into our backyard

Security

Humanity is moving towards a new reality

Astronautics

Innovations in human astronautics

Popular articles

One of Asgardia’s priority missions is the birth and raising of the first human child in space. Astronautics

Asgardia’s parliament – a year of progress

Astronautics

Space industry prime directive

A coronal mass ejection caused by a huge electromagnetic explosion on the surface of the Sun. Such explosions send out billions of protons and electrons, in a superheated ball of plasma, into the solar system. Environment

Solar superstorms and their effects on Earth