Here are the first results of the measures collected by the instruments on board the Mars Atmosphere and Volatile Evolution NASA, thanks to which begins to take shape the complex web of interactions between the solar wind and the Martian atmosphere.
The first scientific results begin to arrive from the probe MAVEN NASA, dedicated to the study of the atmosphere of Mars. After having entered the orbit of the Red Planet last September, started the calibration phase of its tools and have also passed without any problems the close encounter with Comet Siding Spring, MAVEN started from 16 November to do what it is designed: the science of the highest level.
The first analysis of the data collected immediately put in evidence the presence of a process through which the solar wind can penetrate into the deeper layers of the Martian atmosphere, thus contributing to its impoverishment. “We are beginning to shed light on the chain of events that cause the loss of atmosphere on Mars,” says Bruce Jakosky, principal investigator of MAVEN. “During the mission we can reconstruct in detail what happens, reconstructing how the atmosphere of this planet is changed in time.”
MAVEN is designed to move on an orbit which allows it to cross the ionosphere of Mars – the shell of charged particles which is located in an area between about 100 and 500 kilometers above the surface – which serves as a protective shield to the planet, deflecting ions in the solar wind. However this shield seems not be so impenetrable. The Solar Wind Ion Analyzer of MAVEN, one of its onboard instruments, has surprisingly recorded a stream of particles from the sun that are able to penetrate into the deeper layers of the upper atmosphere and ionosphere of Mars. When the solar wind comes in contact with the offshoots of the atmosphere, its ions gain electrons, becoming neutral atoms and allowing them to spread more easily to altitudes much lower, in the ionosphere to reappear again in the form of charged particles.
This transformation, which contains particles of the solar wind back to the state of ions, is allowing researchers to understand how the solar wind interacts with the Martian atmosphere and how it will be eroded.
To support and integrate these observations, there are also data that are coming from other tools MAVEN. The Neutral Gas and Ion Mass Spectrometer (NGIMS) is working to analyze the gas composition of the upper atmosphere of Mars and better understand the relationship between this region and those related to the lower layers. And then there STATIC (Suprathermal and Thermal Ion Composition) that already a few hours after its activation has identified the ‘polar plumes’ composed of ions that are leaving the atmosphere of Mars. In short, MAVEN just seems to keep its promises and is going to give us a new and unprecedented environmental pollution of the Red Planet.