Curiosity celebrated two years on Mars on August 5, 2014, and is continuing its progress across the surface of the planet. In a tweet on September 2, 2014, Curiosity shared its view of the path ahead and proclaimed, “Head for the hills! I’m driving towards these hills on Mars to do geology work & also search for clouds.”

In this news post from astrobio.net, Dr. Robert M. Haberle, Planetary Scientist at NASA Ames and a team member for the Rover Environmental Monitoring Station (REMS), explains why clouds on Mars are relevant to Curiosity’s astrobiology goals.

REMS is an environmental monitoring station and was contributed to the Mars Science Laboratory (MSL) mission by the Centro de Astrobiologia (CAB) in Spain, one of the NASA Astrobiology Institute’s international partners.