**Author details**

Robert J. Reynolds1,2\* and Mark Shelhamer3

1 Mortality Research and Consulting, Inc., USA

2 Translational Research Institute for Space Health, Baylor College of Medicine, USA

3 The Johns Hopkins University School of Medicine, USA

\*Address all correspondence to: rreynolds@mortalityresearch.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**9**

*Introductory Chapter: Research Methods for the Next 60 Years of Space Exploration*

*DOI: http://dx.doi.org/10.5772/intechopen.92331*

Feiveson AH. Last word on viewpoint:

Challenging the notion that only "big-n" studies are worthwhile. Journal of Applied Physiology. 2014;**116**(9):1254. DOI: 10.1152/japplphysiol.00214.2014

[2] Festinger LA. Theory of Cognitive Dissonance. California: Stanford

[3] Hill AB. The environment and disease: Association or causation? Proceedings of the Royal Society of Medicine. 1965;**58**(5):295-300. DOI: 10.1177/003591576505800503

[4] Pearl J. Causality. Cambridge: Cambridge University Press; 2009. DOI: 10.1017/CBO9780511803161

[5] Reynolds RJ, Bukhtiyarov IV, Tikhonova GI, Day SM, Ushakov IB, et al. Contrapositive logic suggests space radiation not having a strong impact on mortality of US astronauts and Soviet and Russian cosmonauts. Scientific Reports. 2019;**9**:8583. DOI: 10.1038/

s41598-019-44858-0

[1] Ploutz-Snyder RJ, Fiedler J,

Justifying small-n research in scientifically amazing settings:

University Press; 1957

**References**

*Introductory Chapter: Research Methods for the Next 60 Years of Space Exploration DOI: http://dx.doi.org/10.5772/intechopen.92331*
