NASA's MAVEN sends back its first results from Mars
Sen—NASA’s latest probe to reach Mars has sent back its first data to provide clues as to why the planet lost most of its atmosphere.
Mars Atmosphere and Volatile Evolution (MAVEN), which went into orbit on 21 September, has given scientists their first look at a storm of energetic solar particles at the Red Planet.
It has also taken, for the first time by any probe, ultraviolet images of the tenuous oxygen, hydrogen, and carbon coronas surrounding Mars, and allowed a comprehensive map to be made of highly variable ozone in the atmosphere underlying the coronas.
Planetary scientists are thrilled by the data that MAVEN has sent them. But it is only the beginning. Instruments aboard the probe will continue to be calibrated and tested over the next couple of weeks, as MAVEN continues to lower its orbit, before the spacecraft begins its primary science mission in early to mid-November.
The testing will include the MAVEN mission’s Electra telecommunications relay to transmit data between NASA’s latest surface rover, Curiosity, and Earth.
Bruce Jakosky, MAVEN principal investigator at the University of Colorado, Boulder, said in a statement: “All the instruments are showing data quality that is better than anticipated at this early stage of the mission.
“All instruments have now been turned on—although not yet fully checked out—and are functioning nominally. It’s turning out to be an easy and straightforward spacecraft to fly, at least so far. It really looks as if we’re headed for an exciting science mission.”
The storm of high-speed solar energetic particles (SEPs) were blasted from the Sun by a flare that produced a coronal mass ejection on 26 September. Such storms can damage a satellite’s sensitive electronics, but at Mars it is thought they might have helped strip away its atmosphere.
Three images obtained by MAVEN’s Imaging Ultraviolet Spectrograph demonstrate the processes by which atoms of gas escape the martian atmosphere. Image credit: NASA/University of Colorado
MAVEN’s Solar Energetic Particle instrument was able to observe the disturbance caused as the SEPs arrived at Mars on 29 September.
SEP instrument lead Davin Larson of the Space Sciences Laboratory, of the University of California, Berkeley, said: “After traveling through interplanetary space, these energetic particles of mostly protons deposit their energy in the upper atmosphere of Mars.
“A SEP event like this typically occurs every couple weeks. Once all the instruments are turned on, we expect to also be able to track the response of the upper atmosphere to them.”
By observing the hydrogen and oxygen coronas of Mars, MAVEN was recording the tenuous outer fringe of the planet’s upper atmosphere, where it meets space. It is in this zone that atoms which were once a part of carbon dioxide or water molecules near the surface can escape to space.
Since these molecules control the climate, following what happens to them allows NASA scientists to understand the history of Mars over the last four billion years and learn why it changed from having a warm and wet climate to the cold, dry climate observed today. MAVEN used its Imaging Ultraviolet Spectrograph (IUVS), which is sensitive to the sunlight reflected by these atoms, to observe the coronas.
MAVEN remote sensing team member Mike Chaffin, of the University of Colorado, said in a statement: “With these observations, MAVEN’s IUVS has obtained the most complete picture of the extended Martian upper atmosphere ever made.
“By measuring the extended upper atmosphere of the planet, MAVEN directly probes how these atoms escape to space. The observations support our current understanding that the upper atmosphere of Mars, when compared to Venus and Earth, is only tenuously bound by the Red Planet’s weak gravity.”
Finally, IUVS also created a map of the atmospheric ozone on Mars by detecting the absorption of ultraviolet sunlight by the molecule.
MAVEN remote sensing team member Justin Deighan, also of the University of Colorado, said: “With these maps we have the kind of complete and simultaneous coverage of Mars that is usually only possible for Earth.
“On Earth, ozone destruction by refrigerator CFCs is the cause of the polar ozone hole. On Mars, ozone is just as easily destroyed by the byproducts of water vapour breakdown by ultraviolet sunlight. Tracking the ozone lets us track the photochemical processes taking place in the Martian atmosphere.”
This weekend, along with other international spacecraft orbiting Mars, MAVEN will be manouevred to help it avoid being hit by any dust particles from Comet Siding Spring (C/2013 A1) as it passes less than 139,500 km (87,000 miles) from the Red Planet.