**4. Other applications**

In this section, we give a brief overview of alternative applications of PLA for the characterization of exotic environments, for example, at deep sea levels, or the exploration of the surface of extraterrestrial bodies—planets and comets.

Spectroscopy techniques are increasingly becoming important in deep-sea exploration and geochemical assessment of solids and liquids, as they enable rapid, in-situ measurements. Laser-induced breakdown spectroscopy (LIBS) has also been used for the deep-sea exploration [17], that is, the examination of soil, or of water composition. The setup consists of a laser source and an optical bench that is placed in a container that can sustain high hydrostatic pressures and has allowed real-time analysis of the ocean ground. It is expected that similar LIBS apparatus could be used in the future missions involving the exploration of planetary surfaces. In these cases, the laser source could be used to ionize materials of the surface to be probed, which are then introduced into a Time-of-Flight Mass Spectrometer (TOF-MS).
