MESSENGER Begins Fall Toward Sun

NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft was successfully launched this morning at 11:15:56 a.m. PST. The spacecraft will be the first mission to the planet Mercury in 30 years and will be the first spacecraft to ever orbit the innermost planet of our solar system.

When falling toward the Sun, like falling toward the Earth without a parachute, an object begins to accelerate. The fuel requirements for a direct flight to Mercury are cost prohibitive, so MESSENGER will take a looping route using the gravity of the Earth and Venus to slow itself down to the appropriate speed to be captured by Mercury. MESSENGER will arrive at the planet in 2011 to begin a one year mission. Only 40 percent of the planet has been photographed, and most of the images are low resolution.

Because the spacecraft will be operating so close to the Sun, a sunshade is required. The instruments behind the sunshade will enjoy room temperature.