Interstellar Travel: Purpose and Motivations

Front cover
Half title
Full title
Copyright
Contents
Contributors
Contributor biographies
Foreword
Introduction
Chapter 1 - Exoplanets: Where shall we go?
	1.1 Detection methods
	1.2 Exoplanets: A history
	1.3 Demographics
	1.4 Best candidates for life: Top 10
	1.5 Reconnaissance
	1.6 Summary
	References
Chapter 2 - Reconnaissance: Studying the target from afar
	2.1 Introduction
	2.2 Methods of observation
		2.2.1 Direct imaging
			2.2.1.1 Coronagraphs
			2.2.1.2 Gravitational lensing
		2.2.2 Occultation method
			2.2.2.1 Earth-size planet detections using occultation
		2.2.3 Radial velocity
			2.2.3.1 Earth-size planet detections using radio velocity
		2.2.4 Timing stellar variation
	2.3 Detecting life on an exoplanet
		2.3.1 Exoplanet flyby
			2.3.1.1 Breakthrough Starshot
			2.3.1.2 Interstellar probe
	2.4 Space and ground-based exoplanet studies: Future plans
		2.4.1 Large-scale direct imaging systems
		2.4.2 Gravitational lensing
	References
Chapter 3 - The scale of the problem: Interstellar distances, time, and energy considerations
	3.1 Cosmic distances
		3.1.1 Terrestrial distances: The metric system
		3.1.2 Interplanetary space: The Astronomical Unit
		3.1.3 Stellar/galactic distances: Light years and parsecs
		3.1.4 Across the universe: Megaparsecs and gigaparsecs
	3.2 Space transportation fundamentals
		3.2.1 Propulsive thrust
		3.2.2 Specific impulse
		3.2.3 Vehicle velocity change related to mass
	3.3 Travel times: A matter of scale
		3.3.1 Travel time to Moon and Mars using today’s technology
		3.3.2 Spacecraft have left our solar system using fly-bys
		3.3.3 Far Centaurus
			3.3.3.1 Future travel time using gravity assists
			3.3.3.2 Travel time using various advanced propulsion concepts
				3.3.3.2.1 Photon sails
				3.3.3.2.2 Solar–electric sails
				3.3.3.2.3 Fusion rockets
				3.3.3.2.4 Fusion ramjets
	3.4 Energy needs for the journey
		3.4.1 Energy sources
			3.4.1.1 Chemical combustion
			3.4.1.2 Nuclear fission
				3.4.1.2.1 Nuclear fusion
				3.4.1.2.2 Antimatter
				3.4.1.2.3 Solar
				3.4.1.2.4 Beamed energy
		3.4.2 Interstellar vehicles—Total energy needed
		3.4.3 Relativistic effects
			3.4.3.1 Time
			3.4.3.2 Kinetic energy
	References
Chapter 4 - Robots, people, or some combination—What or whom should we send to the stars?
	4.1 Context
	4.2 The origin of technological challenges
	4.3 Interstellar navigation
	4.4 Trusted autonomy
	4.5 Interacting with an interstellar crew
	4.6 Conclusion: A construct for interstellar telepresence
	References
Chapter 5 - Is a solar system-scale civilization a precursor to going interstellar?
	5.1 Human expansion into space
	5.2 The cost of exploration
	5.3 Robotic interstellar exploration
	5.4 Human interstellar exploration
	5.5 Technologies to be developed and their attendant requirements
		5.5.1 Nanoprobes
		5.5.2 Probes
		5.5.3 Von Neumann probes
		5.5.4 Space arks
		5.5.5 Slow starships with hibernated crew
		5.5.6 Fast and relativistic starships
		5.5.7 Unpredictable technological developments
	5.6 Conclusions
	References
Chapter 6 - Maintaining the biocultural health of interstellar voyaging cultures: Lessons from institutions, cultural adap ...
	6.1 Questions and definitions
		6.1.1 Culture
		6.1.2 Institution
		6.1.3 A utilitarian path forward
	6.2 What are the challenges of an interstellar voyaging culture?
	6.3 Long-term maintenance of interstellar voyaging culture
		6.3.1 Maintaining Ultimate Sacred Postulates in an interstellar voyaging culture
		6.3.2 Sample Ultimate Sacred Postulates of an interstellar voyaging culture
		6.3.3 The dimension of time
		6.3.4 Limits to prediction of change in multigenerational interstellar voyaging
		6.3.5 Earthside concerns
		6.3.6 Exotic considerations: Hibernation, DNA voyagers and life extension
	6.4 Concluding comments
	References
Chapter 7 - Evolving humanity: What will become of us?
	7.1 Malleable humans
		7.1.1 Altered gravity
		7.1.2 Radiation
		7.1.3 Spacecraft environments, distance/isolation, and psychological
	7.2 Adapting to space
		7.2.1 Minimizing risks
		7.2.2 Psychological engineering
		7.2.3 Megastructures
		7.2.4 Designing the environment
		7.2.5 Consequences
	7.3 Designing Homo Stellaris
		7.3.1 Basic genetic engineering
		7.3.2 Advanced features
	7.4 Becoming Homo Stellaris
		7.4.1 Designer genes?
		7.4.2 Hacking the genome
		7.4.3 Epigenetics
		7.4.4 The promise of optogenetics
		7.4.5 What’s next?
	7.5 Brave new world
	References
Chapter 8 - Should we colonize (interstellar) space?
	8.1 Introduction
	8.2 The framework
		8.2.1 The astronomical value of the future
		8.2.2 Welfare subjects
		8.2.3 Is the expected value of the future positive?
	8.3 The promise and perils of space colonization
		8.3.1 Set up
		8.3.2 The promise
		8.3.3 The perils
			8.3.3.1 A brief detour on nonwelfarist considerations
			8.3.3.2 Welfarist considerations
	8.4 Conclusion
	References
Chapter 9 - The Fermi Paradox and Astrobiology
	9.1 Prologue: History of the Fermi Paradox and the Drake Equation
	9.2 Life as we know it - Earth as a case study
		9.2.1 How it all began
		9.2.2 How it all evolved
		9.2.3 Life as we don’t know it
		9.2.4 Conclusions
	9.3 Our solar system as a case study for extrasolar systems
		9.3.1 Rocky planets as habitable environments
			9.3.1.1 Earth
				9.3.1.1.1 Pre-life earth
				9.3.1.1.2 The Archaean
				9.3.1.1.3 The anthropocene
			9.3.1.2 Venus as a potential past habitable world
			9.3.1.3 Mars as a habitable world
				9.3.1.3.1 Intro to Mars
				9.3.1.3.2 First mission to look for life elsewhere
				9.3.1.3.3 Methane on Mars
				9.3.1.3.4 How habitability has shifted on Mars
				9.3.1.3.5 Future of Mars astrobiological exploration
		9.3.2 Icy moons of gas giants
			9.3.2.1 Enceladus
			9.3.2.2 Europa
			9.3.2.3 Titan
	9.4 Other solar systems
		9.4.1 The big seven
			9.4.1.1 Proxima Centauri b
			9.4.1.2 TRAPPIST-1 e
			9.4.1.3 GJ 667 C c
			9.4.1.4 Kepler-22 b
			9.4.1.5 HD 40307 g
			9.4.1.6 HD 85512 b
			9.4.1.7 Tau Ceti e and f
		9.4.2 Other habitable exoplanets: GJ 163 c, GJ 581 g, Kepler-1649 c etc…
		9.4.3 Remarks on exoplanet habitability
	9.5 The Fermi Paradox: Challenges in interstellar life detection
	9.6 Afterword
	References
Chapter 10 - Interstellar program risk/benefit trade-offs, and possible mitigation strategies
	10.1 Species risks
	10.2 Societal risks
	10.3 Societal benefits
	References
Index
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