MESSENGER

MESSENGER (for Mercury Surface, Space Environment, Geochemistry, and Ranging) is a Mercury probe launched in 2004 by NASA. It carried out its first Mercury flyby observation in 2008, and after two more such flybys, it entered Mercury orbit in 2011 for a planned one-year primary mission and continued operation until 2015 when it was deliberately crashed into the surface. Instruments:

• MDIS - Mercury Dual Imaging System.
• GRS - Gamma-ray Spectrometer.
• NS - Neutron Spectrometer.
• XRS - X-ray Spectrometer.
• MAG - Magnetometer.
• MLA - Mercury Laser Altimeter.
• MASCS - Mercury Atmospheric and Surface Composition Spectrometer.
• EPPS - Energetic Particle and Plasma Spectrometer.
• RS - Radio Science.