Since the dawn of time, the other planets in our solar system have been veiled in mystery, none more so than Mars. Who built the canals? Where are the Martians? and more recently, Why do so many probes to the planet fail to function? These and similar questions have set off much speculation over the centuries. Rather than send an interplanetary geologist to investigate, NASA has sent the rovers Spirit and Opportunity, which are sending hard facts back to Earth, so we can expect at least partial answers. The mandate of the Mars probes is to search for and characterize a wide range of rocks and soils. In particular, mission designers are looking for clues that there may have been water and/or life on the planet.
The two solar-powered, remote-controlled vehicles are bristling with scientific instruments that can gather information including:
● A pair of high-resolution, colour, charge-coupled device panoramic cameras. We have all seen images of the Martian surface taken with these devices.
● A miniature thermal emission spectrometer. This is useful in determining the mineralogy of rocks and soils from a distance by detecting patterns of thermal radiation. It may spot carbonates and clays, minerals associated with water.
● A rock abrasion tool or grinder. This item can drill a hole about 45 mm in diameter and 5.0 mm deep into a rock (not sufficient to outline a good gold deposit).
● A microscopic imager to examine close-up the surface features of selected material.
● An alpha-particle x-ray spectrometer. This will study the elemental chemistry of the Martian surface.
● A Mossbauer Spectrometer. This instrument is designed to study iron-bearing minerals, providing highly accurate determinations of their composition and abundance.
Probably nothing we discover on Mars will become an economic mineral producer. An understanding of rock formations there might someday be applied to the mineral exploration industry on Earth, but that would be far down the road. We explore for the same reasons people have always explored: To exercise our minds and imaginations.
The price tag for each of the rovers is reported to be US$400 million. That kind of money could have been used to find many mineral deposits on Earth. Compared with the investment needed to develop a world-class greenfields mining project, the cost of the rovers can be called "moderate".
The estimated cost of sending a manned mission to Mars is US$11 billion. Somewhere in that budget should be provision for a geologist and a diamond drilling team.