Mariner 10 was a NASA probe whose primary objective was to observe the atmosphere, surface, and physical characteristics of Mercury and Venus. It was a low-cost mission completed for under $98 million.[6] Mariner 10 was launched at 12:45 am EST on November 3, 1973, from Cape Canaveral.[7] Since Mercury is so close to the Sun it was too difficult to incorporate an orbit around Mercury in the route so Mariner 10 orbited the Sun.