This Demonstration shows the approximate orbits of LISA, a space-borne gravitational wave detector. LISA consists of three satellites in a heliocentric orbit, trailing the Earth by 20 degrees. The three spacecraft form an equilateral triangle 5 million km (0.033 AU) a side. In this Demonstration, the default value for the spacecraft distance is increased by a factor of 10.
The LISA orbits are designed to keep the distance between the spacecraft approximately constant over the course of an orbit. The triangular constellation is inclined by 60 degrees with respect to the ecliptic; the three spacecraft orbit the Sun in independent Kepler orbits with a semimajor axis of AU and a small eccentricity and inclination. To first order in the eccentricity , the coordinates of the spacecraft are
where the eccentricity is given by the distance between the spacecraft and , where is the initial phase.