The MESSENGER

Four years of prime orbiting experience around Mercury has given scientists on Earth a lot to smile about. The MESSENGER spacecraft, a probe built by NASA in an effort to study the closest planet to our Sun, has recently crashed into Mercury after its mission has been declared finished. The probe left Earth in 2004, reached Mercury in 2008, and has orbited the planet since 2011. Throughout all this time, MESSENGER has been sending meaningful data back to scientists about the rocky planet, but most notably about its magnetic field. In fact, the most valuable data about Mercury's magnetic field was taken in the fall of 2014 and in early 2015, when the probe flew as low as 15 kilometers above the surface - as compared to 200 and 400 kilometers as it used to. The purpose behind orbiting so low was to collect data on the intrinsic magnetism of rocks on Mercury's surface. The results of analysis showed that the magnetic field of Mercury is extremely ancient, dating back to 3.7 and 3.9 billion years old. This compares to the planet's initial formation, which is believed to be dated at approximately 4.5 billion years ago. "If we didn't have these recent observations, we would never have known how Mercury's magnetic field evolved over time," said Johnson, also a scientist at the Planetary Science Institute. "It's just been waiting to tell us its story." Besides Earth, Mercury is the only planet within the inner solar system known to host such a magnetic field. Interestingly enough, how did engineers even get MESSENGER in orbit around Mercury without it getting pulled into the Sun? Surely the gravitational interactions would have perturbed the probe out of its initial orbit, even the temperatures would have melted it! Thankfully, even though the challenges were immense, the engineering team managed to keep MESSENGER out of trouble by: 1. Attaching a protective sunshield to keep the side of the probe facing the Sun cool. 2. Designing specific elliptical orbits so that the probe would have time between each orbit to cool off. 3. Keeping it away from the Sun's gravitational pull by designing an orbital maneuvering system around Mercury. Talk about mission success!