A story that began 11 years ago has finally come to an end. NASA’s Messenger spacecraft crashed into the surface of Mercury on April 30. The spacecraft launched from Cape Canaveral Air Force Station on Aug. 3, 2004. Traveling at 10.68 kilometers per second, the 7.9 billion-kilometer journey took just over six years and seven months to complete. Messenger was one of only two spacecrafts ever to orbit Mercury. The first was Mariner 10 in 1974-1975, and it has provided many data concerning the planet. Making contact on March 18, 2011, the spacecraft has successfully carried out two missions over the course of four years.
There were several objectives of the mission, including determining core composition, surface composition, nature of the exosphere, geological history and the nature of the global magnetic field. The first extended mission of Messenger was to map the surface of the planet. The images give a glimpse of the planet’s history through the structure of its surface. The main obstacle to the mission was Mercury’s close proximity to the sun, which would put stress on the orbit of the spacecraft, and the heat released from the surface of the planet posed a threat to the sensitive equipment. Once these two factors were accounted for, the spacecraft entered its 12-hour orbit around the planet. The craft completed its primary goal and its extended mission over the course of two years, providing scientists with thousands of pictures and the first evidence of water at the northern and southern poles of the planet.
From the data of Messenger, mission scientists have published several papers concerning topics from surface composition, which is composed of notable levels of magnesium and calcium in the dark zones (areas located at the poles forever shaded from the sun’s rays), to volcanic activity. Much of the history of the planet is littered with volcanic eruptions and meteorite impacts that have taken place over millions of years. The turbulent history of the planet has left it scarred with craters and flat, smooth plains where lava once flowed. Additional data has shown the presence of organic compounds present in the permanently shadowed pools of water ice located at the poles of the planet.
The craft received its second, and final, mission extension on March 17, 2013. The second extension lasted two years and ended with the crash in April. On the day of the crash, scientists used the last of the fuel to slow the descent and obtain images of the surface as the spacecraft hurtled toward the surface of the planet. Hundreds of images were transmitted successfully back to Earth, but thousands more from the crash will remain forever lost. It will be several years before another spacecraft makes its way to that sector of our solar system, and when it does, it will find a new crater on the planet’s surface.
The information for this article was supplied by NASA.