All the chemical and mineralogical evidence suggests that there have been no warm and wet periods in Martian history.

ECONOMIST: Martian chronicles

Once this procedure is complete, a tiny sample will be delivered to the onboard labs, Sam and CheMin, to run chemical and mineralogical analyses.

BBC: Nasa's Curiosity Mars rover to scoop sand sample

The subsequent analysis will reveal the precise chemical and mineralogical compositions present in the powder, giving scientists clues as to the likely conditions under which the rock formed.

BBC: Curiosity Mars rover spins its rock drill

The hope is that mineralogical and geochemical analysis of the three samples will allow researchers to find new ways of identifying possible Martian meteorites, both in the wild and among existing meteorite collections.

ECONOMIST: Meteorites

As well as using the rover's X-ray spectrometer on Whitewater Lake and Kirkwood to determine the chemical elements present, and thus get a better idea of their mineralogical composition, the team needs to work out the order and position of the rock layers to tell them something of their relative ages.

BBC: Nasa's 'Oppy' rover could be rolling on Martian clays