The 2004 launch of NASA's Messenger probe marked the start of the first mission to the innermost planet in the Solar System since Mariner 10's three flybys in 1974. Messenger is looking at the side of Mercury that Mariner 10 couldn't photograph and is studying the planet's magnetic field and dense core, which is believed to make up at least 60% of its mass.
Having completed a series of flybys, in 2011 it will enter a year-long orbit of the planet.
A key mission goal is to explain why Mercury is the only inner planet besides the Earth to have a global magnetic field.
Photo: Messenger prior to launch (NASA)
After 30 years, there is another mission to Mercury.
Sir Patrick Moore talks to Dr David Rothery about Messenger's Mercury images.
The Messenger probe is looking at the side of Mercury that Mariner 10 couldn't photograph and is studying the planet's magnetic field and dense core. Having now completed a series of flybys, in 2011 it will enter a yearlong orbit of the planet.
BBC News's Christine McGourty reports on Messenger's mission.
In a 14 January 2008 BBC News report, science correspondent Christine McGourty reports on Messenger's mission at Mercury as the spacecraft prepares for its first flyby of the innermost planet in the Solar System. She speaks with Alison Boyle from London's Science Museum.
MESSENGER (whose backronym is MErcury Surface, Space ENvironment, GEochemistry, and Ranging, and which is a reference to the Roman mythological messenger, Mercury) was a NASA robotic spacecraft that orbited the planet Mercury between 2011 and 2015. The spacecraft was launched aboard a Delta II rocket in August 2004 to study Mercury's chemical composition, geology, and magnetic field.
The instruments carried by MESSENGER were used on a complex series of flybys – the spacecraft flew by Earth once, Venus twice, and Mercury itself three times, allowing it to decelerate relative to Mercury using minimal fuel. During its first flyby of Mercury in January 2008, MESSENGER became the second mission after Mariner 10's 1975 flyby to reach Mercury.
MESSENGER entered orbit around Mercury on March 18, 2011, becoming the first spacecraft to do so. It successfully completed its primary mission in 2012. Following two mission extensions, the MESSENGER spacecraft used the last of its maneuvering propellant and deorbited as planned, impacting the surface of Mercury on April 30, 2015.