Following the last Apollo lunar mission in 1972 and the subsequent Apollo missions in Earth orbit, including the Apollo-Soyuz joint American and Soviet mission and the Apollo Skylab missions, America's manned space program migrated to the Space Shuttle. The shuttle is set to retire in 2010 and America will have no manned space program unless conceptual plans for a program called "Constellation" are brought to fruition. Under the Constellation program, NASA would return crews to the moon in a vehicle called the "Altair" lander that borrows heavily from the experience gained in landing the Lunar Module on the lunar surface during Apollo. This plastic model is being used to scale up mock-up versions of the lander for purposes of design and feasibility testing.