Mars has been in the news a lot lately, because of a series of exciting discoveries made possible by an armada of spacecraft. Watching how these revelations have forced some established concepts off the table and allowed new ideas to emerge, I feel somewhat hesitant to discuss how my own contributions may stand the test of time. Planetary science, though, is not for the overly cautious—its practitioners stretch the limited available data to its limits, and are hardened to the notion that mistakes will be made in its interpretation.

My foray into Mars science began when I analyzed meteorites as a Harvard geology graduate student. These meteorites turned out to be Martian rocks, blasted off the planet’s surface by impacts. The number of these Martian meteorites has now expanded to more than 30, due largely to new recoveries from Antarctica and African deserts. My most-cited papers are those that review and synthesize what we have learned from several decades of research on the mineralogy, petrology, and geochemistry of these samples. If there is a lesson here for young researchers, it is that staying focused on a topic (rather than dabbling) pays dividends. That is not to say that scientists should not delve into new projects. Rather, they should continue long-term interests and layer on new ones as they gain experience.

Because of my Martian meteorite research, I was viewed as a person who knew a great deal about Mars rocks and so in 1996 was invited to participate in NASA’s Mars Pathfinder, a rover mission which offered the first opportunity to analyze rocks on the planet’s surface. Since then, I have participated in the Mars Global Surveyor and Mars Odyssey orbiters, both of which are presently mapping the planet using remote sensing, and the Mars Exploration Rovers (Spirit and Opportunity), both of which continue to explore locations on the surface. Some of my other highly cited papers (which commonly have students as coauthors) have dealt with discoveries about Mars rocks and soils made during these spacecraft missions.

The common thread in my research on Mars is planetary materials—rocks and dirt. The minerals that make up rocks and soils, their textures, and the abundances of the elements and isotopes that comprise them all provide constraints on the composition of Mars and the processes that have shaped its surface and interior over time. This information is gathered either by measurements made in the laboratory or by remote sensing instruments (usually spectrometers of some sort), and my research involves both approaches. But what makes planetary science most interesting is its interdisciplinary nature. Planetary materials constitute only a modest niche in planetary science, and these scientists who use imagery to study landforms and construct geologic maps, or who analyze geophysical data to study aspects of planetary interiors may outnumber planetary petrologists, geochemists, and spectroscopists. Data from all these sources fit together (usually) to make a coherent story, and fitting the puzzle pieces together is great fun. We’ve only scratched the surface, and there’s plenty of room for new scientists.