Quick work! Just eight hours after entering Martian orbit Sunday, NASA's MAVEN spacecraft sent data back to Earth that scientists quickly translated into the mission's first images. Rendered in primary colors, the ultraviolet snapshots show three different aspects of the Red Planet's atmosphere -- and give a first taste of the data to come.
Scientists with the Mars Atmosphere and Volatile EvolutioN mission hadn't officially planned on receiving significant images so quickly as the spacecraft settled into its weeks-long commissioning phase, adjusting its orbit and readying its instruments. But it was just too good of an opportunity to pass up, said lead scientist Bruce Jakosky, a planetary scientist at the University of Colorado in Boulder.
"We didn't know if we'd be able to do these observations, so we didn't announce it in advance," Jakosky wrote in an email, because it depended on how smoothly MAVEN entered Mars orbit. Because it went well, he said, "we were able to turn several of the instruments on very quickly."
The false-color images taken from the Imaging Ultraviolet Spectrograph instrument show the Red Planet from 22,680 miles above the surface in three different wavelength bands of ultraviolet light. The blue image shows UV light from the sun bouncing off of a giant cloud of scattered atomic hydrogen. The green image shows the light reflecting off of atomic oxygen -- unlike the vast hydrogen cloud, it seems to hug Mars, because oxygen is heavier and can't escape the planet's gravity as easily. The image in red shows UV sunlight bouncing off of the planet's surface -- and the bright spot near the bottom is from either polar ice or clouds. The scientists also put together a composite image from all three UV bands.
Since oxygen and hydrogen come from the breakdown of water and carbon dioxide, they offer clues as to how these key molecules moved through and ultimately escaped Mars' atmosphere, which was once thought to be quite Earth-like, boasting puffy clouds and clear lakes. But it's now less than 1% the thickness of Earth's.
In an earlier interview, Jakosky noted that the orbital insertion went so smoothly that the team had enough fuel left potentially for a full decade of work (the primary mission is set to last one year). Now it turns out that the well-executed maneuver also had some immediate benefits for MAVEN's science goals.
"This week is the only time in the entire mission that we'll have apoapsis (highest point in the orbit) this high," he wrote. "Tomorrow, we'll be lowering it and in a much smaller, lower orbit."
That's why the researchers took these observations as fast as they did, Jakosky said. MAVEN started out in a 35-hour orbit high above the planet, but it's gradually lowering itself into a much tighter, 4½-hour orbit. Up high, they can actually see the shells of oxygen and hydrogen extend to very high altitudes -- which isn't a chance they'd get later in the mission.
"Frankly, I was surprised that the IUVS team was able to turn their data into images so quickly," Jakosky wrote. "They worked through two nights to be able to do it, and I was delighted we could release them so quickly!"