NASA Mission Provides Its First Look at Martian Upper Atmosphere October 14, 2014 The hydrogen and oxygen coronas of Mars are the tenuous outer fringe of the planet’s upper atmosphere, where the edge of the atmosphere meets space. In this region, atoms that were once a part of carbon dioxide or water molecules near the surface can escape to space. These molecules control the climate, so following them allows us to understand the history of Mars over the last four billion years and to track the change from a warm and wet climate to the cold, dry climate we see today. MAVEN observed the edges of the Martian atmosphere using the Imaging Ultraviolet Spectrograph (IUVS), which is sensitive to the sunlight reflected by these atoms.

The Newest NASA Mars Mission Is Already Unraveling The Mystery Of Mars’ Missing Atmosphere  OCT. 15, 2014 This water has broken apart into its atomic components, hydrogen and oxygen, and once hydrogen reaches the upper atmosphere of Mars it escapes into space because it is extremely light and so is weakly bound by Mars’ gravity. It’s escape process like these that remove water from Mars, Chaffin explained, and may have “dominated the history of Martian climate change.”

The hydrogen slipping away from the planet is shown by the bright white band around the red circle, which marks the outline of Mars. The band is bright because the hydrogen atoms are reflecting the sunlight that is shining on that half of Mars during daytime.

Carbon is heavier than hydrogen and so is located closer to the surface as shown in the image below. Carbon dioxide is the most abundant molecule in the Martian atmosphere and, because it is a greenhouse gas, may have established conditions on early Mars for liquid water.

Oxygen is also a heavy element and is therefore more strongly bound by Mars’s gravity. However, chemical interactions between light particles and oxygen atoms in the atmosphere can heat oxygen atoms up to the point where they have enough energy to rise to the upper atmosphere and escape into space.

Most of the oxygen shown in this image is cold oxygen, but the fuzzy part of the image on the list portion of the planet is hot oxygen that is escaping into space. Oxygen is perhaps the most useful element to study because it is produce from the breakdown of both carbon dioxide and water.

An artist’s concept depicts Comet Siding Spring (2013 A1) hurtling towards Mars. Closest approach to Mars comes on October 19, 2014. (NASA)

Three views of an escaping atmosphere, obtained by MAVEN’s Imaging Ultraviolet Spectrograph. By observing all of the products of water and carbon dioxide breakdown, MAVEN’s remote sensing team can characterize the processes that drive atmospheric loss on Mars. (University of Colorado/NASA)

A comet will give Mars a historically close shave next weekend, and NASA aims to be ready for the dramatic cosmic event. The space agency has already trained a number of its science assets on Comet Siding Spring , which will zoom within 87,000 miles of Mars on Oct. 19 — about one-third the distance between Earth and the moon. And NASA’s fleet of Red Planet orbiters and rovers will be watching on the big day, studying the comet and its influence on Mars’ atmosphere. (Wochit)

A general view of Mars, captured by Mastcam:Left onboard NASA’s Mars rover Curiosity on January 27, 2013 (AFP Photo/NASA / JPL-Caltech / MSS/AFP/File)