via the Times.
During the recent deliberations over what NASA should be doing with its astronauts, one suggestion was missions towards one of the Lagrange points, where several space telescopes orbit or are stowed. Objects with large amounts of mass, like planets, stars or moons, create dents in space-time in which they sit. If you have a system of one object orbiting near another, Lagrange points, peaks and troughs in space-time, will appear. There are five of them. In the Earth-Sun system there’s one in front and one behind of the Earth, one either side at the points of Earth’s orbits sixty degrees down from the tangent to where Earth presently is and finally one on the point of Earth’s orbit at the opposite side of the Sun.
As these are peaks and troughs, moving from one to another is simply the same as dropping down or moving up a slope. This is a little different from the normal way of moving a spacecraft which is to imagine a series of orbits about the Earth initially, then the Sun if the probe needs to travel interplanetary, then around the destination. Spacecraft need to boost themselves from one orbit to the next.
Now a team of scientists has worked out the positions of the various Lagrange points (Sun-planet and planet-moon) in order to open up the sloping way of moving about to spacecraft. Leader, Professor Shane Ross of Virginia Tech university, in the United States, believes that the method will not lead to any significant developments in interplanetary space, but it could well improve say missions designed to observe moons in other planetary systems – such as Cassini’s observations of Titan and Enceladus at Saturn.