When we look up at the night sky, we can’t help but be in awe of all of the planets we can see with the naked eye. Mercury has always been a bit of an enigma, however, due to its proximity to the Sun and its relative lack of visibility. For centuries, scientists have been trying to unlock the secrets of this planet, but it was only in 2004 that a spacecraft was finally sent to do just that.The spacecraft was called MESSENGER, and its mission was to explore the planet Mercury. It was a joint mission between NASA and other international space agencies, including the European Space Agency and Japan’s Institute of Space and Astronautical Science. It took off from Earth in 2004 and arrived in orbit around Mercury in 2011.
For four years, MESSENGER carried out its mission to unlock the secrets of Mercury. One of its most important accomplishments was determining the surface composition of the planet. This allowed us to get a better understanding of its geological history and revealed some fascinating details about its internal magnetic field. Additionally, MESSENGER confirmed that polar deposits on Mercury were dominantly composed of water-ice.
One of the most remarkable things about this mission was that it pushed human technology to its limits. MESSENGER had to endure incredibly high temperatures as it flew close to the Sun and carried out its mission near Mercury’s orbit. Its thermal protection system allowed it to survive these extreme conditions, allowing us to gain a wealth of knowledge about this mysterious planet. MESSENGER’s mission ended in 2015 when it slammed into Mercury’s surface after having successfully completed its orbit around the planet. The spacecraft gave us a much better understanding of this mysterious world and helped us unlock some of its secrets,We now know more about Mercury than ever before, thanks to this mission.
Exploring Mercury with MESSENGER.
MESSENGER was launched at 06:15:57 UT Aug. 3, 2004, into an initial parking orbit around Earth. After that, its PAM-D solid motor fired to put the spacecraft on an escape trajectory into heliocentric orbit at 0.92 × 1.08 AU and 6.4 degrees inclination to the ecliptic. To reach Mercury, MESSENGER had to make several gravity-assist maneuvers through the inner solar system, including one flyby of Earth (Aug. 2, 2005), two flybys of Venus (Oct. 24, 2006, and June 5, 2007), and three flybys of Mercury (Jan. 14, 2008, Oct. 6, 2008, and Sept. 29, 2009). The gravity-assist techniques allowed the spacecraft to overcome the problem of massive acceleration that accompanies flight toward the Sun while also conserving propellant for its orbital mission.
Once in orbit around Mercury in March 2011, MESSENGER began collecting data about the planet’s geology, magnetic field and chemical composition. The spacecraft captured stunning images of the planet’s craggy surface and intricate topography. It also revealed evidence of an ancient ocean beneath its surface which could have existed for billions of years. Additionally, MESSENGER discovered new information about Mercury’s magnetic field and its complex interactions with the solar wind – findings that could help scientists better understand how planets form in general.
The mission also provided invaluable pieces to the puzzle of how the solar system evolved over time and offered insight into our planet’s own history. For example, during a flyby of Venus in 2006, MESSENGER relayed back a vast amount of data about the planet’s upper atmosphere which helped scientists better understand our own climate change. The spacecraft also studied particle and fields characteristics of Venus which were coordinated with ESA’s Venus Express mission – providing even more insights into our own planet’s evolution over time.
On September 2009, MESSENGER’s mission to explore Mercury took an unexpected turn when the spacecraft entered a safe mode and, as a result, collected no data on Mercury. Fortunately, the spacecraft revived seven hours later and was finally able to enter orbit around Mercury at 00:45 UT March 18, 2011. This was nearly seven years after launch; however, it marked the start of an incredible mission. A mosaic of our solar system taken by MESSENGER on February 18, 2011 was truly remarkable. It showed all the planets of our solar system except Uranus and Neptune! The spacecraft had also taken nearly 100,000 images of the surface of Mercury and the data collected revealed some amazing findings.
The high concentrations of magnesium and calcium discovered on Mercury’s night side were one such finding. Further studies revealed that there was a significant northward offset of Mercury’s magnetic field from the planet’s center. Additionally, there were large amounts of water in Mercury’s exosphere and evidence of past volcanic activity on the surface. In order to further explore these findings and monitor the solar maximum in 2012, NASA decided to extend MESSENGER’s mission by a year. During this extended mission, three engine firings helped reduce the orbital period from 12 hours to 8 hours. By April 20, 2012, MESSENGER had taken its 100,000th photograph from orbit and had globally mapped both in high-resolution monochrome and in color, the entire surface of the planet.
On April 30, 2015, MESSENGER crash-landed on the surface of Mercury after 11 years in space. The mission was filled with unexpected surprises and groundbreaking discoveries, including the unprecedented discovery of water ice at Mercury’s poles. The spacecraft’s journey began in August 2004 with the launch of the MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) mission. This spacecraft was designed to take pictures of Mercury and study its environment and composition. The original mission was meant to last only one year, but was extended until March 2015 due to its success.
The most remarkable discovery made during MESSENGER’s mission was the evidence of frozen water at Mercury’s poles, even though the planet’s rotational axis has almost no tilt. This finding contradicted previous theories about the planet’s environment and provided valuable insight into the formation of our solar system. In addition to its breakthrough discoveries, MESSENGER also set records during its extended mission. In February 2014, the spacecraft took its 200,000th orbital image, far exceeding initial expectations. That summer, controllers began gradually moving MESSENGER to a very low orbit to conduct a new research program. On Christmas Day 2014, it became clear that the spacecraft had run out of propellant and would likely crash on Mercury in late March 2015.
On April 16, 2015, NASA announced that MESSENGER would impact Mercury by April 30th. After one last maneuver to raise the orbit enough to continue science activities into early spring, the spacecraft eventually ran out of fuel and slammed into the planet’s surface at about 8,750 miles per hour (14,080 kilometers per hour). This collision created a new crater near the Janácek crater in Suisei Planitia,the impact marked the end of a remarkable mission that revealed much about our solar system.