sentence: Satellite imagery shows that there is frozen ground water on the planet.
sentences_before: The 'colonization of Mars' by humans is an ongoing debate among scientists. They want to colonize the planet Mars.
sentences_after: That makes Mars the best choice for a thriving colony off the Earth. The Moon has been proposed as the first location for human colonization. However, Mars has a thin atmosphere. Because of this, it has potential to host humans and other organic life.
concept_name: satellite imagery
headings: Colonization of Mars
categories: Mars Space colonization