All timelines of future events are just extrapolations of the past, but relatively good predictions are possible if we recognize the complexities. Technology in particular has a way of confounding prognosticators, as it races far ahead of expectations along some avenues while stagnating in others once believed to be imminently explosive. The reasons for this are numerous, but boil down to the fractal nature of progress - i.e., every advance brings its own problems and issues to work out, so a given achievement only occurs if the limit of its recursive problem-solution loop converges on a practical, economical system.
Using this understanding, I offer the following timeline, which I construct not so much as specific predictions but as an average distribution of advances along increments that make technological sense. In other words, one specific advance may in reality occur only 5 years after the one that facilitates it, and give rise to the next logical advance 15 years later, but my predictive standard would guess that it would happen 10 years after its immediate cause and give rise to its immediate effect 10 years later. Timeline after the fold.
I should note, as I do in the title, that I consider this an "optimistic" timeline. This is because I completely ignore any major circumstance that could seriously disrupt progress - e.g., global catastrophe, war, political or economic upheaval, etc. I am not happy with this timeline, as it places the most glorious progress outside my expected lifespan, but I remain hopeful that mankind (and my own health) will pleasantly surprise me. This is, of course, total speculation, but I love it just the same.
Note: I haven't speculated on developments in space-based solar power, because it's at the nexus of too many variables, and could literally happen in a decade or a century.
2010-2020:
- Initial commercial manned suborbital and orbital flights.
- Initial private robotic exploration (Google Lunar X-Prize)
- Initial, small-scale private manned orbital installation(s).
- Total orbital capacity: 15 people at a time.
- Total permanent ET population: 0
2020-2030:
- Thousands of manned suborbital flights per year.
- Number of people to orbit per year: 20
- A couple more private, manned orbital installations.
- Three more private robotic expeditions to the Moon, and possibly one to an asteroid.
- American or international manned lunar expedition, using a lot of commercially-derived hardware.
- Initial orbital fuel depot.
- Total orbital capacity: 20 people at a time.
- Total lunar surface capacity: 5 people at a time.
- Total permanent ET population: 0
2030-2040:
- Point-to-point suborbital transport.
- Tens of thousands of suborbital flights per year, for tourism or transportation.
- Number of people to orbit per year: 50
- Five to ten private, manned orbital installations.
- A few high-capability corporate/industrial robotic lunar missions, some under contract from NASA, the military, or other governments.
- Numerous small-scale academic and commercial lunar robotic operations.
- A few more private robotic expeditions to asteroids / Mars orbit.
- Additional governmental manned lunar missions, establishment of permanently-crewed Antarctica-style base.
- Private manned circumlunar flight.
- Expansion of orbital fuel depot capacity by factor of 2 or 3.
- Total orbital capacity: 70 people at a time.
- Total lunar surface capacity: 10 people at a time.
- Total permanent ET population*: 1
*I am guessing that this is when some eccentric billionaire will move to orbit and live there. The lunar base doesn't apply, as nobody actually lives there - it's permanently crewed, not inhabited, and everyone only stays there for six months or a year at a time.
2040-2050:
- Hundreds of thousands of surborbital flights per year, largely for transportation.
- Number of people to orbit per year: 100
- A few dozen manned orbital installations, some with limited permanent accommodations for a handful of residents.
- Industrial robotic exploration of the lunar surface; remotely-operated test-beds for mining, processing, manufacturing, and material return.
- Large-scale commercial/academic robotic exploration of the lunar surface, with affordable consumer services, games, toys, general experimental platforms, and other applications proliferating.
- Initial corporate sponsorship of robotic exploration beyond the Moon - handful of missions, none farther than Jupiter.
- First private robotic Mars lander.
- Gradual increase in number of commercial/academic robotic missions to Mars and asteroids.
- A few private manned circumlunar flights per year.
- Expansion of core public-sector lunar base, creation of a few satellite campuses operated by individual countries.
- Orbital fuel depot capacity increases by order of magnitude.
- Total orbital capacity: 200 at a time
- Total lunar surface capacity: 15 at a time
- Total permanent ET population: 3
2050-2060:
- Suborbital flight completely replaces long-distance aircraft flights - millions of passengers per year.
- Number of people to orbit per year: 500-1000
- Crewed installation at EML-5 (Earth-Moon Lagrange point 5).
- Existing orbital installations rapidly expand capacity through modular additions. Launch/construction of new installations levels off, but some are designed for permanent habitation.
- Initial teleoperated mining of Moon rock - originally for sale to scientists, engineers, collectors, jewelers, and other retailers.
- First private manned lunar surface exploration.
- Large, highly developed terrestrial services and entertainment economy centered on unmanned lunar commercial applications.
- Widening corporate exploration of Main Belt asteroids; a few orbital probes to Mars; initial robotic exploration of Jupiter and Saturn systems.
- Several private Mars landers - academic and commercial, with some corporate sponsorship - and increasing numbers of cheap, low-functioning orbiters.
- Initial international human Mars mission, using VASIMR propulsion.
- Ten private circumlunar manned flights per year.
- Public-sector lunar base and nationally-run satellite campuses expand to include far-flung research facilities of varying purposes and staff numbers - significantly expands capacity.
- Orbital fuel depots become established industry with regular, predictable growth.
- Total orbital capacity: 5,000
- Total lunar surface capacity: 50
- Total permanent ET population: 20
2060-2070:
- Suborbital and orbital industries converge with scale and volume, leading to single broad class of vehicle capable of efficiently doing either. Radical expansion in orbital flight.
- Number of people to orbit per year (by decade's end): 50,000
- First child born in space (sparks ethical debate).
- Some orbital installations grow sufficiently to begin having to deal with social problems - first glimmerings of space-based culture.
- Private manned stunt missions to achieve various objectives: E.g., break from the Earth's gravity and make one orbit of the Sun; orbit Mars; visit an Earth-crossing asteroid.
- Establishment of Earth-Moon cycler system: Dedicated in-space vehicles that never land on Earth or the Moon, but shuttle between LEO and lunar orbit installations.
- Lunar mining and manufacturing scales up.
- Several private manned operations on the Moon, and also public-sector operations representing various agencies of various governments.
- Corporate, commercial, and academic robotic exploration of Main Belt and Mars continues, but increases only linearly, with occasional plateaus.
- Establishment of small, periodically-crewed international Mars base.
- Several hundred circumlunar manned flights per year.
- Total orbital capacity: 100,000
- Total lunar surface capacity: 300
- Total Mars capacity: 3
- Total permanent ET population: 2,000
- Space-born: 1
2070-2080:
- Expansions in size and efficiency of ground-to-orbit vehicles, reductions in cost, economies of scale, and broadening price-competition further expand orbital travel.
- Number of people to orbit per year: 150,000
- Handful of children born in space, almost certainly in centrifuged stations (gravity needed for embryonic development). Beginning of the field of exo-obstetrics.
- First sincerely* declared nation-statehood of an orbital settlement.
- Numerous other sociopolitical/economic firsts for LEO settlements.
- EML-5 and lunar orbit grows in proportion to lunar surface traffic.
- Initial robotic asteroid mining attempted on Earth-crossing asteroid.
- Regular commercial lunar robotic sector expands to asteroids and Mars; Phobos and Deimos are inundated.
- Private stunt mission - manned Venus flyby.
- Public-sector Mars base achieves maximum planned staff levels, plateaus at small number of crew.
- Thousands of cislunar flights per year.
- Establishment of first lunar installation for express purpose of settlement - probably claims citizenship in terrestrial nation for first few decades.
- Total free-space capacity (orbit and beyond): 150,000
- Total lunar surface capacity: 2,000
- Total Mars capacity: 6
- Total permanent ET population: 5,000
- Space-born: 5
*I'm sure there will officially be sovereign entities in space before this, but probably just as tax havens.
2080-2090:
- LEO starts to become crowded, leading to mutually-agreed upon regulations and driving development in higher orbits.
- Number of people to orbit per year: 200,000
- Number of space-born increases slowly.
- Additional orbital sovereignties established or declared. Some claims possibly resisted by terrestrial entities.
- Main Belt asteroid robotic mining pilot-projects based on experiments with near-Earth asteroid mining; large-scale characterization of available resources and tracking of object velocities and positions.
- Corporate-sponsored manned expedition to Phobos and Deimos with mining test-beds.
- Corporate, academic, and commercial robots swarm the Martian surface; exploratory, scientific, and industrial test-beds.
- Public-sector progress on Mars stalls: Discoveries made and technologies tested, information gained, but crew number and mission frequency does not increase.
- Public-sector human visit to Ceres.
- Additional lunar settlements.
- Private manned stunt missions: Mercury flyby, comet, distance records, etc.
- Total free-space capacity: 200,000
- Total lunar surface capacity: 15,000
- Total Mars capacity: 6
- Total permanent ET population: 20,000
- Space-born: 20
2090-2100:
- Earth-to-orbit transport begins to level off at a fixed rather than proportional increase.
- Research and development into space elevator (or the related concept, orbital tower) ramps up.
- Number of people to orbit per year: 250,000
- Results of initial Main Belt asteroid and Phobos/Deimos mining enter the market and begin affecting commodity prices.
- Phobos and Deimos commercial bases expanded.
- Commercial manned mission to Martian surface, establishment of base.
- Modest increase in public manned operations on Mars in response to private advances.
- VASIMR permits international manned mission to Jupiter system.
- Stunt private visits to Main Belt asteroids.
- Lunar surface infrastructure undertaken - roads between major settlements and installations; recharge stations for surface rovers; fuel depots for point-to-point rockets.
- Beginnings of lunar politics.
- Biological issues with prenatal development in lunar gravity probably worked out or avoided by now - native lunar population expands.
- Total free-space capacity: 400,000
- Total lunar surface capacity: 30,000
- Total Mars capacity: 15
- Total permanent ET population: 50,000
- Space-born: 300
2100-2110
- Elevator/tower full-length orbital test bed constructed.
- People to orbit per year: 300,000
- Rather than driving mining of more asteroids, success of Main Belt robotic and Phobos/Deimos manned mining primarily drives scaling-up of current operations. Additional hardware is sent, infrastructure created, and crew sent to Mars orbit.
- Commercial tourist bases also established on Phobos/Deimos.
- Second commercial Mars base established.
- Public Mars operations plateau again.
- Additional public-sector manned missions to Jupiter system: First human landings on Callisto, Ganymede, and Europa.
- Sovereign lunar settlements may begin to have disputes with terrestrial entities over resource claims - initially polite disagreements, since population remains low.
- Total free-space capacity: 600,000
- Total lunar surface capacity: 70,000
- Total Mars capacity: 30
- Space-born: 2,000
2110-2120:
- First-generation operational elevator/tower constructed. Traffic to space explodes (and not in a bad way).
- People to orbit per year: 600,000
- Current mining operations having achieved equilibrium, new firms enter the market and the number of asteroids being mined increases. As the amount of material available on a single asteroid is huge, the number is still probably less than 10.
- Traffic from Phobos and Deimos mining leads to commercial development of Earth-Moon-Mars cycler sytem - drastically reduces cost of getting to Mars and increases frequency of human travel.
- Public-sector Mars efforts switch to commercial cycler transport and are able to send more people, so base expands.
- Private Mars bases expand modestly in number and size - modestly because still relatively expensive to land and live there.
- Establishment of international scientific outpost on Callisto - safest radiation environment of the Galilean moons. Continued manned exploration of Jupiter system, robotic exploration of Trojan asteroids.
- Small manned corporate base on Ceres: Coordinates Main Belt robotic mining, but also takes tourists and contracts as a way-station for public Jupiter exploration.
- Lunar politics becomes noticeable, but influx continues to swamp native culture.
- Total free-space capacity: 1.5 million
- Total lunar surface capacity: 150,000
- Total Mars capacity: 100
- Space-born: 10,000
2120-2130:
- Earth-to-orbit elevator/tower operations become reliable and efficient, leading to awesome explosion of human traffic to space.
- People to orbit per year: 2 million
- Lunar space elevator constructed. Traffic to the Moon explodes. Less-than-dirt-cheap raw materials due to asteroid mining have cascading effects throughout economy, changing what materials are used in what applications. Industry consolidates to maintain profits.
- First Mars settlement - installation inhabited by people who intend to live there permanently.
- Due to explosion in space traffic, Mars capacity skyrockets.
- First private manned visit to Jupiter system (stunt).
- Callisto outpost maintains size and mission.
- Corporate base on Ceres expands to accommodate more commercial applications; leases out to other business or public tenants.
- Rapid influx to Moon causes civil, cultural, and economic disruption - the first popular political movements and riots.
- Livable volume in free space is now commoditized, and habitats mass-produced.
- Free-space capacity: 3 million
- Lunar surface capacity: 500,000
- Mars capacity: 1,000
- Space-born: 50,000
2130-2140:
- People to orbit per year: 5 million
- Earth and Moon economies increasingly merge.
- A few additional Mars settlements.
- Large-scale corporate robotic exploration of Jupiter system and Trojans.
- Handful of tourist flights to Jupiter for ultra-wealthy patrons.
- Slight expansion in size of Callisto outpost.
- First Ceres settlement.
- Although lunar population continues to radically expand, a new social balance is achieved and marvelous works of art and culture occur.
- Free-space capacity: 20 million
- Lunar surface capacity: 1.5 million
- Mars capacity: 10,000
- Space-born: 200,000
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Okay, now I'm boring even myself. But you get the idea of how damnably gradual this is going to be even if we ignore possibilities like Kessler syndromes, lunar or Mars gravity being physiologically harmful over the long-term, plagues ravaging vulnerable low-population settlements, meteorites or solar flares wiping out entire settlements, catastrophes drastically curtailing the economic capabilities of Earth-bound society, wars, etc. etc. Still, if I ignore my own mortality, this timeline still sounds pretty cool.