Moon missions are essential to the exploration of more distant worlds. Extended lunar stays build the experience and expertise needed for the long-term space missions required to visit other planets. The moon may also be used as a forward base of operations on which humans learn how to replenish essential supplies, such as rocket fuel and oxygen, by creating them from local material.
Such skills are essential to the future expansion of human presence into deeper space.
The Constellation Program has near-term scientific objectives as well. Although humans have visited the moon before, our closest neighbor still harbors its own scientific mysteries to be explored—including the investigation of water ice near the moon's poles.
Future human moon missions will be preceded by robotic reconnaissance launches, between 2008 and 2011, to scout landing sites that may have the most resources available to astronauts. The moon's south pole is considered particularly promising because it is rich in hydrogen and may be home to water ice as well.
A New Spacecraft
These new NASA missions are being spearheaded by the development of a state-of-the-art new spacecraft—but one with a retro feel.
The Orion crew exploration vehicle echoes the design of the original Apollo missions but updates its systems with modern technology. The new capsules will also be larger, with three times the volume capacity and the ability to accommodate a four-person crew. The new size has led NASA officials to describe the mission as "Apollo on steroids."
The Orion capsule, which launches attached to a solid rocket booster and Apollo-like upper stage, is seen as a safer and more reliable design for future space exploration than the now-familiar space shuttle.
Once in space the flexible Orion vehicles will take astronauts to and from the International Space Station. They will also enter lunar orbit, a position from which landers can repeatedly visit the moon's surface.
The Orion capsules, which may be reused up to ten times, will parachute to Earth like those of yesterday—though they will arrive on dry land rather than via ocean splashdowns.
In the years beyond 2020, these spacecraft may aid in assembling Mars-bound vehicles in orbit to take the first humans to the red planet.
