VoyagerHaving spent six years wrangling with various mission profiles for a “Grand Tour” of the outer solar system, made possible by a favorable planetary alignment occurring only once every 175 years, NASA finally authorizes a very stripped-down version of its original ambitious Grand Tour plans. The Mariner Jupiter/Saturn ’77 mission will consist of two twin unmanned spacecraft to be launched in 1977, each on a course to explore Jupiter, and then to use Jupiter’s gravity to deflect them to Saturn. These spacecraft will be renamed Voyager 1 and Voyager 2 just a few months before lifting off.