eLISA Mission

Key Features

eLISA's spacecraft in a near-equilateral triangular formation and the "cartwheel" orbits. Credit: NASA

eLISA - Triple Orbit


Dr. Benjamin Knispel

Albert Einstein Institute Hannover


Tel.: +49 (511) 762-19104

Fax: +49 (511) 762-2784


Callinstr. 38

30167 Hannover, Germany


Key features of eLISA are interferometric measurement of distances, million-km long baselines, drag free spacecraft based on inertial sensors, and the familiar “cartwheel”-orbits.

eLISA uses precision laser interferometry across 106 km of space to compare separations between test masses that are protected by the spacecraft from non-gravitational disturbances. The distance measuring system is a continuous interferometric laser ranging scheme, similar to systems used for radar-tracking of spacecraft.

One of eLISA´s key features is the set of three orbits in a near-equilateral triangular formation, described under the mission concept. The eLISA orbits ensure a stable thermal environment, minimising thermal disturbances on the spacecraft and the inertial test masses. Another key technology of eLISA are free-falling test masses inside each spacecraft. The test masses will be undisturbed by forces other than gravitation.

A new technology, the so-called “drag-free” operation, allows the spacecraft to follow the test masses, all the while shielding the test masses from spurious forces.

next chapter: 

no content specific images

no content specific videoclips found

no content specific sounds

No Scientific Papers

no content specific publications

No news attached to this article