MESSENGER is a scientific investigation of the planet Mercury, the least explored terrestrial planet. Understanding Mercury and how it was formed is essential to understanding the other terrestrial planets and their evolution. Mercury has been visited by only one other spacecraft, Mariner 10, so we know little more than its average density (the second greatest of all the planets), the composition of its atmosphere (thinnest of the terrestrial planets), the fact that it posses a global magnetic field, and its extreme variations in temperature. MESSENGER continues to lift some of the uncertainty about this innermost planet of our solar system.
The MESSENGER mission entered into orbit around Mercury after making three flybys of the planet, using data collected during the flybys as an initial guide to perform a more focused scientific investigation of this mysterious world. MESSENGER is investigating six key scientific questions about Mercury’s characteristics and environment with a set of miniaturized space instruments. The spacecraft entered Mercury orbit in March 2011 and carried out comprehensive measurements for one full Earth year. MESSENGER’s extended mission began on March 18, 2012, and ended one year later. The team is awaiting word from NASA on a proposal for a second extended mission. In the meantime, instruments aboard the spacecraft continue to gather new data on Mercury and its environment.
MASCS: Mercury Atmospheric and Surface Composition Spectrometer
LASP developed and built the MASCS instrument onboard MESSENGER. MASCS is designed to detect minerals on Mercury’s surface, and determine the abundance and components of its thin atmosphere. Data from MASCS will help answer the questions: What is Mercury’s surface made out of? How is Mercury’s atmosphere generated? Does Mercury have ice at its poles?