The MESSENGER mission to Mercury: Development history and early mission status

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission, launched 3 August 2004, will be the first spacecraft to orbit the planet Mercury. Mercury holds answers to several critical questions regarding the formation and evolution of the terrestrial planets. The MESSENGER mission will fly by Mercury in 2008 and 2009 and will orbit Mercury for one Earth year beginning in March 2011. The >14 kW m−2 solar thermal input and the large velocity change required to reach Mercury orbit make this a very challenging mission from thermal and mass perspectives. MESSENGER overcomes these challenges with innovative applications of existing technologies and materials. Seven miniaturized instruments, along with the spacecraft telecommunications system, satisfy all scientific objectives of the mission. The Mercury flybys are preceded by gravity assists at the Earth (2005) and at Venus (2006 and 2007). This paper offers an overview of mission history and objectives, spacecraft and payload, current status, and data acquisition plans.