On October 19, two European Space Agency spacecrafts arrived at Mars, right on schedule. But while one crash-landed on the red planet’s surface (ESA scientists are still trying to figure out what happened to poor ol’ Schiaparelli), the other safely inserted itself into orbit. And last week, the ExoMars orbiter sent home its first images.
An onboard camera called CaSSIS—Color and Stereo Surface Imaging System—snapped these pics. In the past weeks, it has blinked online for just a few hours at a time, taking experimental shots, like a beginner art student pointing her camera at nothing in particular. This is in advance of the orbiter’s main job: sniffing out and cataloguing trace gases like methane, a possible indication of life. After ExoMars’ other instruments identify a gas, it’s CaSSIS’s job to look around on the Martian surface to figure out what source might’ve dealt it.
CaSSIS powered up for the first time in space for a fully-configured testing phase and generally, things look pretty good. The scientists needed to know whether everything worked: how quickly the camera could capture images, how fast the telescope rotated, whether the images overlapped correctly so they could be stitched together. The camera was a lot more sensitive to light than they expected—which was a nice surprise, says Antoine Pommerol, a planetary scientist at the University of Bern in Switzerland. And CaSSIS has great, sharp focus, which you can see in the images. But sometimes, the scientists found, the camera’s aim is off: a short lag means it might miss a particular feature on the surface that it’s trying to capture.
CaSSIS isn’t as high-res as some cameras on other Mars spacecraft (like NASA’s Mars Reconnaissance Orbiter, for instance), but it has other capabilities. For one, it comes equipped with four different color filters, which allow scientists to tease out the mineralogy of the surface, telling one iron-based mineral from another, or whether an area is rife with olivine or just has high clay content. And CaSSIS takes stereo images, which lets researchers assemble the photos to reconstruct particular areas in 3D. That’s useful for keeping track of Mars’s various slopes, which can slump because of ice condensing or subliming away.
Those capabilities will come in handy when the data-gathering portion of the mission begins in earnest in 2018. Then, CaSSIS will photograph specific, promising target sites suggested by scientists and the public. “It’ll be a firehose of data,” says Nicolas Thomas, the principal investigator on CaSSIS. Before that, though, the team has to make sure everything works just right, and that means test shots like the ones above, where they couldn’t really choose what they were imaging.
These are no planetary glamour shots. “We didn’t bother putting it in color, purely because it was boring,” says Thomas—the areas they photographed were so full of dust that they completely covered the mineralogy underneath. (Though, does anyone really ever tire of photos from other planets?) Scientifically, they’re valuable because they tell Thomas and the rest of the CaSSIS team that the instrument is working. They can use the information to develop better calibration tools, populate a database of targets, and generally get ready for the real deal.
And this camera work is important, Thomas says, because it’s vital to have instruments monitoring the Red Planet—especially as the current ones age. “Mars is a lot more geologically active than we imagined 15 years ago,” he says. “Things change.” And science needs pics of those changes, or they (basically) didn’t happen.
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