NASA鈥檚 Mars Reconnaissance Orbiter has sent home its first close-up pictures of the Red Planet. They show a portion of a massive canyon as well as bright patches of what appears to be water ice near Mars鈥檚 north pole.
MRO went into orbit around Mars in March. It is equipped with the most powerful camera ever sent to another planet, the High Resolution Imaging Science Experiment (HiRISE).
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The camera took some pictures shortly after arriving at Mars, when it was in a much wider orbit around the Red Planet (see New Mars probe delivers stunning colour image).
Now, it has beamed back images taken from less than 300 kilometres above the planet鈥檚 surface. The new images were taken on 29 September and show parts of Mars in unprecedented detail.
Grand canyon
One image shows Ius Chasma, a branch of the planet鈥檚 colossal Valles Marineris canyon. Long worm-like features at lower right appear to be sand dunes shaped by wind.
Layered rock, seen especially in the bright areas at mid-right and lower left, may hold clues to Mars鈥檚 past, says HiRISE team member Nicolas Thomas of the University of Bern in Switzerland.
The number of craters present there can be used to estimate how much time has passed since the layers were laid down, Thomas says. This will help 鈥減iece together some sort of sequence of events鈥� at the site, he told 快猫短视频.
A second image shows an area at 86.5掳 north, very close to the north pole. Layers of dust mixed with ice can be seen in a sloping cross section, possibly caused by sunlight sublimating frozen carbon dioxide on a hillside.
The layers are laid down with different thicknesses as a result of variations in Mars鈥檚 climate. HiRISE鈥檚 unprecedented resolution will allow the layers to be probed in finer detail than ever before in order to understand these climatic shifts, Thomas says.
The images will help tide scientists over until they can physically drill down into the polar ice caps to investigate the planet鈥檚 past, Thomas says: 鈥淭he only way we can do this now is with remote sensing using a high-resolution camera.鈥�
Melting water
Among the database of more than 5000 targets the HiRISE science team hopes to look at, Thomas is particularly keen on studying places where gullies have cut into steep slopes on the planet. Some scientists believe these features were carved by melting water ice (see Landslips, impacts and eroding ice revealed on Mars).
HiRISE has also taken some colour images, which the science team is still processing and plans to release in a few days. 鈥淔rom working on it, I can already tell you that it鈥檚 going to be good,鈥� says Thomas.
An image has also been obtained with MRO鈥檚 Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). It has lower resolution than HiRISE but can make detailed measurements of the light spectrum of the areas it looks at, which allows it to map out their chemical compositions.
The image was taken on 27 September and shows three views of the same long strip of Mars鈥檚 northern polar region. The left hand strip was made with visible light and is close to true colour. The other two strips show the strip in two different combinations of infrared wavelengths. In the right-hand strip, ice appears blue and dust yellow.
