The NASA spacecraft Messenger, living out the last days of its unprecedented and unexpectedly long mission, will try to scrutinize the planet of the inner part of the solar system, facing it in two weeks.
After the consumption of the last fuel reserves on April 30, the Messenger will begin to yield to the gravitational pull of this strange world, which has been its home since March 2011. The purpose of the mission was to collect detailed geochemical and other data that will help scientists understand how Mercury was formed and developed. Mercury is one of the four rocky planets in the solar system, along with the shrouded clouds of Venus, filled with the life of the Earth and dry, cold Mars.
After two extended missions, the scientists received a six-week bonus after the engineers came up with a way to create pressure in the spacecraft's fuel tank to gain some height. The last impulse, scheduled for April 24, will help lift the probe from a height of six miles to 12 miles above the surface of the planet, adding six more days (40 orbits) for the study. "The messenger is going to create a new crater on the surface of Mercury in the near future .... but let's not be sad," NASA employee John Grunsfeld said on Thursday before the event to celebrate the results of the scientific mission.
The last days of the Messenger were one of the most productive: the device found that, despite the fact that Mercury is close enough to the Sun, the planet has ice inside craters located near the poles, which are never exposed to direct sunlight.
Image analysis reveals a dark, possibly carbon-rich material covering the ice in one crater, later named “Fuller” in honor of architect Richard Buckminster Fuller. This could happen when an ice comet or a carbon-rich asteroid crashed into Mercury.
The messenger also found bright spots inside some craters, called “relics.”
"The relics are unexpected formations. They are among the youngest features on the planet, and this suggests some sort of material instability," said leading scholar Messenger Sean Solomon from Columbia University. Similar features were found on the water-rich planet Dwarf Ceres, which is about to become the target of detailed explorations of NASA's Dawn spacecraft.
Another key result of the study are: topographic features, showing that Mercury has shrunk by more than 4 km in diameter, its core is gradually cooled, and its surface is dotted with volcanic deposits, showing the rich history of the planet.
The messenger also discovered that Mercury has a strange and unexpectedly asymmetrical magnetic field.
Solomon also noted that the most significant finding of the mission is that despite being close to the Sun, Mercury has volatile elements, such as potassium and sulfur, which should have evaporated.
The amount of volatile substances is about the same as on the planet Mars. It challenges the theory of how planets form.