Why do we need humans on Mars to search for life?

Why astronaut are essential to the astrobiological exploration of Mars

Jonathan Clarke

Humans have been exploring Mars from orbit for 55 years and the martian surface for 44 years via robotic missions.  Currently there are five active Mars orbiters and one active rover.  Another two orbiters and two rovers will be sent to Mars in the next two months.  Hopefully a few of these will be successful.  Robotic missions have collected almost all the data we have about Mars. However to truly explore Mars we will need direct human presence.  While robotic stations and orbiters are ideal for monitoring the martian environment  on the surface and from orbit, and are crucial as pathfinders and scouts, their capabilities are extremely limited compared to astronauts with regard to detailed exploration and study of the martian surface, including astrobiology.

Based on reasonable extrapolation of Apollo experience to likely constraints of crewed Mars missions, these are likely to be several orders of magnitude faster, and more capable than even the most capable robotic missions in exploring the planet.  This conclusion is supported by comparing the amount of effort required to discover and understand life’s earliest habitats on Earth in regions such as the Pilbara of western Australia.  No likely advance in robotic technology, is likely to narrow the gap, especially when robotic capabilities have been consistently over sold over the past 50 years. Furthermore, many advances in robotic missions, such more capable and compact instruments, advantaged materials, and improved power sources, are likely to advance also crewed missions and their supporting equipment such as tools, instruments, environment suits, vehicles, and habitats.

Crewed missions on Mars will not eliminate the need for robotic missions, but will shift their focus towards specific, human centred, roles.  Mars orbiting satellites, automated environmental monitoring stations, automated machinery for resource utilisation in support of Mars bases, teleoperated equipment for exploration of especially hazardous nor fragile locations, will proliferate. Roboticists need not fear obsolescence!

Direct human presence on Mars will also require shifts in our perception of planetary protection and methods of astrobiological exploration, more appropriate to human capabilities. These may contrast with present standards which are driven by someone arbitrary values and the constraints of the limited methods available to robotic exploration.