In Situ Analysis
Pros. The advantages of in situ analyses on Mars include the following:
Cons. The disadvantages of in situ studies of martian samples include the following:
Value of Complementary Approach
In situ measurements conducted in the context of a sample-return mission have the following desirable characteristics:
Various methods have been proposed to acquire martian samples. These include grab sampling (using a scoop or arm on a lander or collection of airborne dust during a flyby through the upper atmosphere), sampling a variety of rocks and soils by using a rover, obtaining subsurface samples using a drill, conducting a Phobos sample return that might contain Mars ejecta from large impacts, or collection by astronauts.
To maximize the astrobiological potential of a sample return from Mars, it will be important to recover a wide range of materials from a well-characterized site of astrobiological interest. This requirement immediately raises a longstanding strategic question: Is it appropriate to wait until sufficient knowledge has accumulated to identify the “right sample” or to get a sample from the best place identifiable today? Proponents of the “right sample” approach typically argue that spending billions of dollars to return the “wrong sample” would be a major setback to the Mars Exploration Program. The biggest concern about getting the “right sample” is that, once this approach