**Conflict of interest**

*Mars Exploration - A Step Forward*

advances in the coming decades. As soon as technology readiness allows it, returning samples to Earth for analysis with the best available instrumentation is the next reachable step in the exploration effort. In this framework, the Mars Sample Return (MSR) program is designed as a joint effort between NASA and ESA, defining a complex sequence of missions beginning with the Perseverance rover, selecting and caching the first samples. Later, an ESA rover will be sent sometime during the decade (2026?) to retrieve and store the samples to be placed in a Mars Ascent Vehicle (MAV) that will place the samples in orbit, where they will wait until a

These complex mission designs, launches, and operations' sequence will constitute a major milestone in the Martian exploration, where the next step will be the

The robotic exploration of Mars is a consequence of humanity's awe toward our red neighbor and has become a reality when technology has reached the needed maturity, also influenced by other socio-economical aspects. The space race of the 1960s and the 1970s was the starting point of the Martian exploration and is a good example of how technological development was pushed beyond unimaginable limits thanks to the social, political, and economic support. In the late 1970s, however, the race had already been won over by the United States, and economies were suffering the petrol crisis. This resulted in a loss of momentum in the exploration missions to Mars, and the missions to Mars stopped until the implementation of the

The MEP is an ambitious program for the exploration of Mars, which was conceived as an exploration effort based on an international collaboration, aimed at joining efforts among the different space agencies worldwide. This set a new era in the exploration of Mars, where not only collaboration between Agencies is needed for mission's preparation, but also cooperation is required among different instruments once on Mars to give proper answers to scientific challenges. This has resulted

into complex rover designs and missions where a suite of experiments works

paving the way for the human exploration of the red planet.

one of the most transcendental questions of humankind: Are we alone?

Authors acknowledge Spanish institutions: Instituto Nacional de Técnica Aeroespacial (INTA) and Universidad de Valladolid (UVa), as supporting institutions for authors professional activities, and Ministerio de Ciencia e Innovación (MICINN) for its funding support through grants ESP2014-56138-C3-1-R, ESP2014-56138-C3-2-R, ESP2107-87690-C3-1-R, ESP2107-87690-C3-3-R.

The decade of the 2020s will set new milestones in the Martian exploration paradigm, not only for pushing the technological limits and conquering new dimensions of explorations (helicopters, subsurface drilling), but also achieving the final step in the Mars studies evolution observations (with telescopes from Earth, from orbit, *in situ* from surface, etc.), bringing home (Earth) Martian samples for its study,

In this new era, the collaboration between instruments, rovers, missions, and, finally, agencies and political actors will be key to obtain the best results to, ultimately, unravel the mysteries of our red neighbor and, who knows, maybe answer

return-trip ship captures them to bring them to Earth for analysis.

design of *in situ* manned missions to Mars.

Martian Exploration Program in the 1990s.

altogether for a common goal.

**Acknowledgements**

**6. Conclusions**

**106**

The authors declare that they have no conflicts of interest with respect to research, authorship and/or publication of this book chapter.
