NASA's Mars Atmosphere and Volatile Evolution Mission (MAVEN) that completed 1,000 Earth days in orbit around the Red Planet on Saturday has come up with multiple discoveries, revealing how the Sun stripped Mars of most of its atmosphere.MAVEN is the first spacecraft dedicated to understanding Mars' upper atmosphere and began its primary science mission in November 2014. The spacecraft aims to determine the role that loss of atmospheric gas to space played in changing the Martian climate through time. "We're excited that MAVEN is continuing its observations. It's now observing a second Martian year, and looking at the ways that the seasonal cycles and the solar cycle affect the system," said Gina DiBraccio, MAVEN Project Scientist at NASA, in a statement.MAVEN has also measured the rate at which the Sun and the solar wind are stripping gas from the top of the atmosphere to space, along with the details of the removal processes.It has been observed that a layer of metal ions in the Martian ionosphere results from incoming interplanetary dust hitting the atmosphere.
The spacecraft also discovered that some particles from the solar wind are able to penetrate unexpectedly deep into the upper atmosphere, rather than being diverted around the planet by the Martian ionosphere."MAVEN has made tremendous discoveries about the Mars upper atmosphere and how it interacts with the sun and the solar wind," said Bruce Jakosky, Principal Investigator, University of Colorado, Boulder. "These are allowing us to understand not just the behaviour of the atmosphere today, but how the atmosphere has changed through time," Jakosky added.MAVEN observed the distribution of gaseous nitric oxide and ozone in the atmosphere that showed unexpectedly complex behaviour.This complexity indicated that there are dynamical processes of exchange of gas between the lower and upper atmosphere that are not understood at present.