[meteorite-list] MAVEN Spacecraft Detects Aurora and Mysterious Dust Cloud around Mars

[Ron Baalke]

March 18, 2015
     
NASA Spacecraft Detects Aurora and Mysterious Dust Cloud around Mars

NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft has observed 
two unexpected phenomena in the Martian atmosphere: an unexplained 
high-altitude dust cloud and aurora that reaches deep into the Martian 
atmosphere.

The presence of the dust at orbital altitudes from about 93 miles (150 
kilometers) to 190 miles (300 kilometers) above the surface was not 
predicted. Although the source and composition of the dust are unknown, there 
is no hazard to MAVEN and other spacecraft orbiting Mars.

"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.

The cloud was detected by the spacecraft's Langmuir Probe and Waves (LPW) 
instrument, and has been present the whole time MAVEN has been in operation. 
It is unknown if the cloud is a temporary phenomenon or something long 
lasting. The cloud density is greatest at lower altitudes. However, even in 
the densest areas it is still very thin. So far, no indication of its 
presence has been seen in observations from any of the other MAVEN 
instruments.

Possible sources for the observed 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. However, no known process on Mars can explain the appearance of dust 
in the observed locations from any of these sources.

[Image]
A map of IUVS' auroral detections in December 2014 overlaid on Mars' 
surface. The map shows that the aurora was widespread in the northern 
hemisphere, not tied to any geographic location. The aurora was detected in 
all observations during a 5-day period.
Image Credit: University of Colorado

MAVEN's Imaging Ultraviolet Spectrograph (IUVS) observed what scientists have 
named "Christmas lights." For five days just before Dec. 25, MAVEN saw a 
bright ultraviolet auroral glow spanning Mars' northern hemisphere. Aurora, 
known on Earth as northern or southern lights, are caused by energetic 
particles like electrons crashing down into the atmosphere and causing the 
gas to glow.

"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," 
said Arnaud Stiepen, IUVS team member at the University of Colorado. "The 
electrons producing it must be really energetic."

The source of the energetic particles appears to be the sun. MAVEN's Solar 
Energetic Particle instrument detected a huge surge in energetic electrons 
at the onset of the aurora. Billions of years ago, Mars lost a global 
protective magnetic field like Earth has, so solar particles can directly 
strike the atmosphere. The electrons producing the aurora have about 100 
times more energy than you get from a spark of house current, so they can 
penetrate deeply in the atmosphere.

The findings are being presented at the 46th Lunar and Planetary Science 
Conference in The Woodlands, Texas.

MAVEN was launched to Mars on Nov. 18, 2013, to help solve the mystery of how 
the Red Planet lost most of its atmosphere and much of its water. The 
spacecraft arrived at Mars on Sept. 21, and is four months into its 
one-Earth-year primary mission.

"The MAVEN science instruments all are performing nominally, and the data 
coming out of the mission are excellent," said Bruce Jakosky of CU LASP, 
Principal Investigator for the mission.

MAVEN is part of the agency's Mars Exploration Program, which includes the 
Opportunity and Curiosity rovers, the Mars Odyssey and Mars Reconnaissance 
Orbiter spacecraft currently orbiting the planet.

NASA's Mars Exploration Program seeks to characterize and understand Mars as 
a dynamic system, including its present and past environment, climate cycles, 
geology and biological potential. In parallel, NASA is developing the human 
spaceflight capabilities needed for its journey to Mars or a future 
round-trip mission to the Red Planet in the 2030's.

MAVEN's principal investigator is based at the University of Colorado's 
Laboratory for Atmospheric and Space Physics, and NASA's Goddard Space Flight 
Center in Greenbelt, Maryland, manages the MAVEN project. Partner 
institutions include Lockheed Martin, the University of California at 
Berkeley, and NASA's Jet Propulsion Laboratory.

For images related to the findings, visit:

http://www.nasa.gov/maven

-end-

Dwayne Brown
Headquarters, Washington
dwayne.c.brown at nasa.gov 
202-358-1726

Nancy Neal-Jones / Bill Steigerwald
Goddard Space Flight Center, Greenbelt, Md.
nancy.n.jones at nasa.gov / william.a.steigerwald at nasa.gov 
301-286-0039 / 301-286-5017

Jim Scott
University of Colorado, Boulder, Colorado
jim.scott at colorado.edu 
303-492-3114