During its 1,000 days in orbit, MAVEN has made a multitude of exciting discoveries. Here is a countdown of the top 10 discoveries from the mission:
10. Imaging of the distribution of gaseous nitric oxide and ozone in the atmosphere shows complex behavior that was not expected, indicating that there are dynamical processes of exchange of gas between the lower and upper atmosphere that are not understood at present.
9. 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; this penetration is allowed by chemical reactions in the ionosphere that turn the charged particles of the solar wind into neutral atoms that are then able to penetrate deeply.
See the remaining eight discoveries here: