Lagrange points

Despite no clear commitment to return to the Moon or venture to Mars, there are a number of committed individuals and groups who have produced countless plans and studies for deep-space exploration, hoping for the day when these plans turn into reality. Aside from a return to the Moon, human exploration of Mars and visits to far-flung asteroids, another target for future human exploration often features in these plans—the so-called “gravity parking sites” in space. Called Lagrange (or Lagrangian) points, these are great expanses of space at which the gravitational forces of the Sun and the Earth are equalized, so any spacecraft placed there could remain in place with little effort. Within the Earth-Moon system there are five such points. They are far enough away from the Sun or planetary bodies that they make ideal places to situate observation platforms,

such as ultra-cold telescopes that measure temperature fluctuations in space. Lagrange points are found around other planets and could be used to site remote operations centers intended to control robotic vehicles to explore the less hospitable places in the solar system more easily.

The L2 point is about 1 million kilometers from Earth and is the target location for the James Webb (infrared) Space Telescope, the replacement for the Hubble Space Telescope. Placing the spacecraft at this point makes servicing from Earth extremely difficult, and until the appearance of Orion or a similar spacecraft it will be impossible for several years to come. Once we have the capability to send crews to these points, they will be able to service and repair the range of telescopes currently being planned to be located there, extending their useful life and expand­ing their science program as in the case of Hubble. It may also be possible to perform construction tasks with large space structures or spacecraft at these points before sending them to the distant reaches of the solar system.

These locations could provide useful preparation points for trips to Mars and for controlling automated spacecraft on the Moon—a sort of Mission Control in space. With the development of more artificial intelligence spacecraft, operating a control room from deeper into space where communications would be much quicker would clearly be more advantageous than waiting for signals sent between

Earth and Mars that would need a 40 min round trip. As Gemini was a step for Apollo to the Moon, perhaps Lagrange points will be a stepping stone to deep-space human exploration missions.