On this day in 2011, NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) probe became the first spacecraft to orbit Mercury. NASA prepared the 10-year summary below explaining MESSENGER’s accomplishments from the time it was launched on August 3, 2004 through August 1, 2014. The probe later impacted the surface of Mercury on April 30, 2015.
NASA issued this high-level summary of the mission:
The MESSENGER spacecraft fundamentally changed our understanding of Mercury during its four-year orbital exploration of the planet, returning nearly 300,000 photographs and a wealth of information from its instruments. The formatted data totaling more than 10 terabytes reside in NASA’s Planetary Data System archive. Among the major findings were that Mercury harbors water ice and organic compounds at its north pole, that volcanism played a major role in shaping the planet’s surface, and that Mercury’s surface materials are more volatile-rich and chemically reduced than expected.
Our Awesome Universe 