What is the chemical composition of the dust and soil on Mars? What is the geochemical history of Mars?  How can we detect biogenic signatures of past or present life?  What can we learn about earth's environment by studying other planets? Does the surface material pose any hazard to future human explorers? How does one make valid chemical measurements in such an environment?

Chemical analyses of the surface and/or subsurface material in remote hostile extraterrestrial environments such as Mars or Europa, presents a truly daunting and unique analytical challenge.  To undertake such missions, with the slightest hope of obtaining meaningful analytical data, requires instrumentation that can withstand rigors far beyond those encountered on Earth.  In addition to mass, volume, and power constraints, such analytical instruments must be able to withstand extreme temperature fluctuations (-140 to 60^oC) and anticipate any unexpected chemical or physical conditions such an alien environment might present.
 

RCAL - A Wet Chemistry Lab for Future Rover Missions

The Robotic Chemical Analysis Laboratory (RCAL) (Figure 1) was concieved as the next generation wet chemistry analytical system for Mars and other planetary bodies. Its design was originally inspired by the MSP'01 MECA Wet Chemistry Laboratories (WCLs) [1] and most recently by the succesful analyses of the Martian soil by the four WCLs on the 2007 Phoenix Mars Lander [2-4]. The RCAL is currently in its final stages of R&D and is being proposed as a geochemical analysis instrument for future rover missions. It expands on the WCL concept by providing twenty individual sealed sample chambers mounted on a rotating carousel. (Figure 2) The soil, after delivery by an external mechanism such as a robotic arm or sub-surface drill, is loaded into a dual soil hopper.  Multiple small samples can then be taken from the hopper and delivered to the test chambers.  After the chamber is punctured, one of a set of four electrodes mounted over the carousel can be inserted into the selected chamber.  The RCAL will enable a variety of bench-top wet chemistry analyses of the Martian soil, assessing its interaction with water and various reagents, and ultimately providing unique scientific information about the geochemical and biological history of Mars. 

The research, development, and integration, of the sampling system/sensor arrays, its incorporation on the deck of a Mars lander/rover mission, and their use to analyze the surface material in a remote hostile environment, poses a unique set of scientific and analytical challenges.