However, the criteria for deciding how each of them should be used, and in what combination, are not usually stated and probably were never formally developed. CHEX believes that decisions regarding the mix of robots and humans to explore the Moon and Mars, and to carry out other scientific investigations in space, should be made with explicit cognizance of the relative strengths and weaknesses of each evaluated in the context of well-defined and specific tasks to be performed. Activities ideally suited to humans include those requiring the techniques of intensive field study and tasks requiring complex, physical articulation combined with expert knowledge and the ability to adapt to new situations. Assessment of complex natural systems makes excellent use of the human capability for serendipitous discovery and response.
Robots have several obvious advantages.
They are inherently expendable and thus should be used in situations in which the risk to humans is excessive or for which there is no clear advantage to using humans. Robots excel at performing repetitive, tedious tasks that are amenable to programming and that do not need or take advantage of unique human capabilities. Lastly, robots can have a duty cycle that is uninterrupted by the need to rest, sleep, or perform the mundane tasks that devour so much time in the everyday life of humans. Although humans offer specific advantages in the exploration of planetary surfaces, they have their limitations as well. Because of the harsh environments of the Moon and Mars and the amount of challenging physical work involved, safety considerations will always constrain the amount of time available for people to explore and perform scientific tasks.