How can life or traces of extant or extinct life, like biomolecules or pre-biotic compounds, respectively, be detected on other planets and moons - within our solar system and beyond? Which missions, tools, sensors have to be developed for their detection and measurements? Moreover, how can geophysical parameters and other environmental conditions be measured that have a bearing on habitability? These are the key questions of ‘Tools and Strategies for Exploration for Planetary Habitability’. It is well accepted in the planetary community that an understanding of habitability requires space missions that are equipped with remote sensing instruments for geological and mineralogical mapping or for in-situ measurements on planetary surfaces. NASA and ESA are planning future planetary space missions, and they support the development of new technologies for these missions according to their programs. However, traditionally space mission instrumentation is rather crude and of limited performance if compared to capabilities in Earth-based laboratories, at least when (analytical) in-situ instruments are concerned.
Among the reasons are: limited availability of mass and power resources, harsh thermal environments, mechanical launch (and landing) loads, and year-long space travel under high radiation levels. Sensors have to be small and low weight but highly reliable and autonomous in operation.
On the other hand, extreme sensitivity is needed for in-situ instruments looking for organic compounds and biogenic molecules because of their low concentrations: the Viking missions have established an upper bound for organics for Mars in the near-surface soil in the ppm range (e.g. Biemann et al., 1977), with no single molecule measured thus far. Several models suggest degradation of organic compounds in the current Martian environment (e.g., Zent and McKay, 1994; Stoker and Bullock, 1997; Yen et al., 2000).
Planetary landing missions with analytical objectives often need to acquire samples of either loose soil or from rocks with subsequent mechanical preparation prior to analyses. Artificial intelligence on board of landed missions could be a useful asset to decide if a sample is worth investigation at all and if yes, with which sensors. This capability would dramatically improve the efficiency of surface operations. By the nature of space missions, the seemingly simple tasks in a laboratory turn to be very difficult for an unmanned space vehicle. For example, Mars rovers were tested in a desert environment on Earth with many life traces. Most of the rovers were unable to autonomously detect traces of life.