Wikipedia
In celestial mechanics, the Lagrangian points (; also Lagrange points, L-points, or libration points) are positions in an orbital configuration of two large bodies where a small object affected only by gravity can maintain a stable position relative to the two large bodies. The Lagrange points mark positions where the combined gravitational pull of the two large masses provides precisely the centripetal force required to orbit with them. There are five such points, labeled L1 to L5, all in the orbital plane of the two large bodies. The first three are on the line connecting the two large bodies and the last two, L4 and L5, each form an equilateral triangle with the two large bodies. The two latter points are stable, which implies that objects can orbit around them in a rotating coordinate system tied to the two large bodies.
Several planets have minor planets near their L4 and L5 points (trojans) with respect to the Sun, with Jupiter in particular having more than a million of these. Artificial satellites have been placed at L1 and L2 with respect to the Sun and Earth, and Earth and the Moon for various purposes, and the Lagrangian points have been proposed for a variety of future uses in space exploration.
Usage examples of "lagrangian point".
The Earth's second Lagrangian point was on the Earth-sun line, but at the midnight point, on the opposite side of the planet from the shield's station.
The UEG and Southern Cross were certain that Liberty was still there in its Trojan Lagrangian point-Number Five-out near Luna's orbit.
Loren could still remember the launching of Excalibur from its construction cradle at the Lagrangian point between Earth and Moon.
The pull of each extended well in toward the inner Lagrangian point, the invisible line down the center of that invisible channel between the two invisible killers.
It was they who fitted the small fusion rockets into each chosen asteroid, computed the course to bring it to a Lagrangian point where it would be gravitationally trapped between the Earth and moon, and sent it to join the procession of mineral chunks that made up the cornerstone of Earth’.
Put it in the Lagrangian point between Belle Terre and the olivium moon.
The Station should be completed, and converted to a surveillance station - maybe even some kind of weapons-bearing battle station - and towed out to l5, the stable Lagrangian point two hundred and forty thousand miles from Earth, at the third corner of a triangle including Earth and Moon.