This is not a movie trailer. This is a real space mission pitch.

Scientists are often accused of doing great science, but not doing very good at selling their science.

Perhaps this very cool 'trailer' is a sign things are changing around that?

It's for LISA—the Laser Interferometer Space Antenna—a European proposal to put three laser-equipped spacecraft into an Earth-trailing orbit and configured in a triangle with each side measuring one million kilometres. It uses lasers between the craft to measure separations down to picometres.

The goal? To detect that elusive phenomenon the gravity wave.


I like it!

This is how the mission purpose is described on the project website:

Gravitational waves are fundamentally different from electromagnetic waves.
Electromagnetic waves, created by the acceleration of electrical charges, propagate in the framework of space and time. Gravitational waves in contrast, created by the acceleration of large bulks of mass, are waves of the spacetime fabric itself. They cause a change in the quadrupol moment of the mass distribution or in other words, time-varying changes in distance between free macroscopic bodies. 

eLISA/NGO will observe passing gravitational waves directly by measuring the tiny changes of distance between freely falling proof masses inside spacecraft. Key features of eLISA/NGO are interferometric measurement of distances, long baselines of 2 x 106 km, drag free spacecraft based on inertial sensors, and the familiar “cartwheel”-orbits.

The relative distance change between two freely falling bodies caused by a passing gravitational wave is exceedingly small, because spacetime is an extremely stiff elastic medium. For example: Gravitational waves of a typical white dwarf binary at a distance of 50pc create a periodic change of only 10-10 m in distance between two test masses, separated by a sufficiently large distance.

A suitable instrument for measuring such small length changes over a broad band of low frequencies is a laser interferometer with an arm length as large as possible and long integration times, the primary impetus for a space-borne detector. 

Hence eLISA/NGO can be thought of basically as a Michelson interferometer in space with an arm length of 1 million km. The arm length has been carefully chosen to allow observation of most of the interesting sources of gravitational waves.

The eLISA/NGO mission consists of one “Mother” and two “Daughter” spacecraft orbiting the Sun in a triangular configuration.

The three satellites, separated by a distance of 1 Mio km, will form a high precision interferometer that senses gravitational waves by monitoring the changes in distance between free falling test masses inside the spacecraft.

A key feature of the eLISA/NGO concept is a set of three orbits maintaining a near-equilateral triangular formation, without the need for station-keeping. Depending on the initial conditions of the spacecraft, the formation can be kept in an almost constant distance to the Earth or be allowed to slowly drift away to about 70 x 106 km, the outer limit for communication purposes.

The centre of the formation is in the ecliptic plane 1 AU form the Sun and 20° behind the Earth. The plane of the triangle is inclined by 60 deg with respect to the ecliptic. These particular heliocentric orbits for the three spacecraft were chosen such that the triangular formation is maintained throughout the year, with the triangle appearing to rotate about the centre of the formation.

eLISA/NGO will coherently measure the stretching and squeezing of spacetime, including frequency, phase, and polarisation. Hence it will shed light on the origin of gravitational waves - large-scale violent cosmic events - and trace the motions of distant matter directly.

Here's hoping it gets funded.