Mars and the Mars Atmospheric Climate Observatory (MACO)

Mars is a very diverse and interesting place that has fascinated humans for many generations. Evidence continues to mount that Mars has had a very active hydrological cycle over its history. Enormous flood channels much larger than anything on Earth reveal that liquid water existed on the surface, if only briefly, and may have flowed into a shallow ocean at northern high latitudes. It is now understood that Mars’ obliquity varies from ~5^o to 45^o over million year time scales dramatically altering the latitudinal distribution of solar heating. Based on evolving geological evidence and modeling results, this heating apparently drives dramatic changes in the distribution of surface water which apparently moves from high latitudes during present conditions to low latitudes at high inclinations. It is not clear if the hydrological cycle in the present climate is in equilibrium or if it is slowly evolving.

Critical to understanding past (and future) behavior is understanding the present hydrological cycle and the processes controlling it. As with Earth, I am very interested in the Martian hydrological cycle and using our ideas developed for Earth to measure and reveal its many secrets.

MACO

William Folkner (JPL) and I conceived the Mars Atmospheric Climate Observatory (MACO) in 2001 in response to NASA’s Mars Scout PI-led mission announcement of opportunity. Mars Scouts are essentially a Discovery-class Principal Investigator-led mission focused on Mars. MACO centers around satellite to satellite radio occultation measurements to profile the atmosphere plus shorter observations to measure dust and aerosols. MACO was one of 10 missions selected to receive funding from NASA to develop our concept (http://www.spacedaily.com/news/mars-scouts-01b2.html). The MACO science concept as defined after the first Mars Scout opportunity is summarized in Kursinski et al., (2004).

Because we could not fit MACO within the then cost cap, we did not submit a proposal in 2002 (and we certainly were not alone). The mission selected for the first opportunity is the Phoenix lander (PI: Peter Smith at UA).

In early 2006, NASA announced the second Mars Scout opportunity with almost a 50% higher cost cap ($475M). We both expanded and refined MACO and submitted the proposal July 2006. We are presently awaiting the announcement, nominally in November, of the 3 Scout concepts selected to proceed into Phase A studies. If MACO is ultimately selected as the 2011 Scout, Phase B will begin January 2008 with launch in late 2011 and a Martian year of operations beginning about a year later. We will build and test the 2 key US instruments at University of Arizona.