Transit of Mercury last four transits occurred on November 15, 1999; May 7, 2003; November 8, 2006; and May 9, 2016. The next will occur on November 11, 2019, and then on November 13, 2032. A typical transit lasts several hours. On June 3, 2014, the Mars rover "Curiosity" observed the planet Mercury transiting the Sun, marking the first time a planetary transit has been observed from a celestial body besides Earth. More generally, transits can also occur for Venus and were investigated in the context of searching for the hypothetical inner planet Vulcan. The most common observation to be made at a
When We Left Earth: The NASA Missions When We Left Earth: The NASA Missions When We Left Earth: The NASA Missions (or NASA's Greatest Missions: When We Left Earth in the UK) is a Discovery Channel HD documentary miniseries consisting of six episodes documenting American human spaceflight, spanning from the first Mercury flights through the Gemini program to the Apollo moon landings, the Space Shuttle, and the construction of the International Space Station. It was created in association with NASA to commemorate the agency's fiftieth anniversary in 2008. It first aired on June 8, 2008, and concluded on June 22. Each airing consisted of two hour-long episodes.