The Orion capsule is poised to make its first test flight Thursday. If all goes as planned, the unmanned vehicle will orbit Earth twice before splashing into the Pacific Ocean. Kim Shiflett/NASA hide caption

itoggle caption Kim Shiflett/NASA

During the Apollo 12 mission, astronaut Alan Bean holds a container of lunar soil. The astronaut Charles "Pete" Conrad, who took the photograph, is reflected in Bean's faceshield. Bean says he used to think that in his lifetime, we'd build a base on the moon and start preparing to travel to Mars. Hulton Archive/Getty Images hide caption

itoggle caption Hulton Archive/Getty Images

The moon appeared bigger and brighter when it went supermoon on June 23, 2013 — especially when it was seen next to objects on the horizon, such as the helicopter from the original Batman television show at the New Jersey State Fair last year. Julio Cortez/AP hide caption

itoggle caption Julio Cortez/AP

China's first lunar rover separates from Chang'e-3 moon lander early Dec. 15, 2013. This picture was taken from the screen of the Beijing Aerospace Control Center in Beijing, capital of China. Li Xin /Xinhua /Landov hide caption

itoggle caption Li Xin /Xinhua /Landov

Staff members make preparations for Chang'e-3's soft-landing on the moon at the Aerospace Control Center in Beijing, on Saturday. Li Xin /Xinhua /Landov hide caption

itoggle caption Li Xin /Xinhua /Landov

The Long March-3B carrier rocket carrying China's Chang'e-3 lunar probe blasts off from the launch pad at Xichang Satellite Launch Center in southwest China's Sichuan Province on Monday. Li Gang /Xinhua /Landov hide caption

itoggle caption Li Gang /Xinhua /Landov