Mars Atmosphere and Volatile Evolution (MAVEN) arrived in orbit around the Red Planet in September of last year. It’s mission is to determine what happened to Mars atmosphere and water.

Since then it has encountered some unexpected phenomenon including a perpetual dust storm and an aurora that reaches deep into the thin Martian atmosphere.

The dust cloud, which stretches from 93 miles to 190 miles above the surface was not expected and has been ongoing for as long as MAVEN has been in orbit.

It was originally detected by the spacecraft’s Langmuir Probe and Waves (LPW) instrument, but it’s source and composition are unknown.

“If the dust originates from the atmosphere, this suggests we are missing some fundamental process in the Martian atmosphere,” said Laila Andersson of the University of Colorado’s Laboratory for Atmospherics and Space Physics (CU LASP), Boulder, Colorado in a statement.

Although the cloud has been present for at least five months, it is still unknown whether it is temporary or a permanent feature of the Martian atmosphere.

Despite it’s longevity, the cloud is very thin even in the lower atmosphere where it is the most dense. None of MAVEN’s other instruments have detected the cloud to date.

NASA has listed several theoretical sources of the dust cloud including “dust include dust wafted up from the atmosphere; dust coming from Phobos and Deimos, the two moons of Mars; dust moving in the solar wind away from the sun; or debris orbiting the sun from comets.”

No phenomenon occurring on Mars, that NASA is aware of, could account for the clouds in the observed locations.

It is not known if there is any relationship between the long-lasting dust cloud and mysterious plumes spotted on the Red Planet in 2012. In March and April of that year plumes, of unknown origin and composition, were seen reaching up to 155 miles into the Martian atmosphere.

Those plumes covered several hundred square miles and remained visible for 10 days. Similar phenomenon have been observed in the past, but none were as large or long lasting.

On December 20 of last year, MAVEN also spotted a bright, ultraviolet aurora across Mars northern hemisphere. These “Christmas lights”, as NASA researchers refer to them, were similar to the aurora seen on Earth, generated by our magnetic field. Mars has no magnetic field of its own.

“What’s especially surprising about the aurora we saw is how deep in the atmosphere it occurs – much deeper than at Earth or elsewhere on Mars. The electrons producing it must be really energetic,” said Arnaud Stiepen, IUVS team member at the University of Colorado.

The source of the aurora appears to be, according to NASA researchers, energetic particles from the sun. MAVEN’s Solar Energetic Particle instrument detected a large and sudden surge in electrons as the aurora began. The loss, billions of years ago, of Mars magnetic field allows particles to directly strike the atmosphere. The solar activity sparked an energy field 100 times more powerful than that produced by a standard house current, allowing the aurora to penetrate deep into that atmosphere.