Lunar lander. Artwork of a lunar lander touching down on the Moon. This lunar lander is part of NASA's Constellation Program, a US space program announced in 2004, which is intended to put astronauts back on the Moon by 2020. The lunar landers will carry crews of four astronauts down to the Moon's surface from an orbiting Orion spaceship. After exploring the Moon, the crew will ascend back to orbit and use the Orion spaceship to return to Earth.