When is the space future supposed to happen? The question is raised by comments on the last couple of posts, especially some of Jean Remy's observations. Among space minded people today a sense of frustration and stagnation is pervasive. But this is largely a result of distorted historical perspective.
We entered space with a spectacular splash, due to particular circumstances, AKA the Space Race. Rather than working up gradually to a lunar expedition by building an orbital station first, as expected in the 1950s, we took it in one straight shot, then woke up with moon rocks in our pockets and a great big hangover. We did what? We went where?
Just as unexpectedly, satellites took over most of the jobs that the 1950s assigned to a space station. Instead of having immediate (and valuable/profitable) tasks, such as weather observation and telecoms relay, a space station is needed only for long term development. The same can be said of human spaceflight itself. Robotic spacecraft serve our current practical needs very well, and they are carrying out our first reconnaissance of the Solar System faster than anyone in the 1950s dreamed. We are not sending people up to watch hurricanes, we are sending them up to learn how to live and work in space.
True, there is a short-term crisis in US human spaceflight - our current architecture is nearing retirement, and its replacement is over budget and behind schedule at best, at worst a major Washington boondoggle. This is a temporary and parochial concern. Abandoning a reusable shuttle in favor of an 'old fashioned' capsule also feels like retrogression, but it merely accepts a reality: The Shuttle, like the Great Eastern, was too much too soon. The technology is not mature enough for an efficiently reusable vehicle, and the traffic does justify one.
Meanwhile people like Burt Rutan are experimenting with lower cost approaches to launch and initial ascent. Whether or not suborbital tourism succeeds as a business, and it might, this work will pay off when the launch market reaches the point of demanding reusable craft.
So what might we expect from here?
The current year round population in space is six. Suppose it were to grow, through the usual fits and starts, at an average 4 percent per year. First we'll try this out on the past. Run backward from 2009, this growth rate gives us three people in space in 1991 - about when Mir entered full service - and one person in 1963, soon after we started traveling in space at all. As predictions of the past go this is imperfect but not bad.
Now let's apply it to the future. Over the next few decades, growth is glacially slow:
2025: 11 people
So two generations from now there are still only 80 people living in space - barely enough for a robust orbital station and minimal outposts on the Moon and Mars. The space population passes 100 in 2081, and by 2101 there are a shade over 220 people in space - just enough, perhaps, to support the sort of travel infrastructure that the movie 2001 pictured for a century earlier.
But in the 22nd century, compound arithmetic starts to kick in:
More than ten thousand people in space is a lot. At this point the human Solar System begins to resemble our familiar image - large orbital stations; regular scheduled passenger service at least to the Moon and perhaps to Mars; space based industries - surely propellant production, likely some mining and fabrication as well.
Continue the same growth rate until 2300 and there are more than half a million people in space, the equivalent of a medium sized city and suggestive of at least incipient colonization.
Any compounding formula, carried far enough, becomes absurd. This one gives 1.4 billion people in space in 2500 and 3.5 trillion in 2700. In real life such trends bump up against something. Short of magitech on the one hand or catastrophe on the other, living in space will remain more difficult and costly than on Earth, so the population will probably settle in at some modest fraction of Earth's population - which might mean anything from a few hundred people to a few million.
But the real point is that the time scale examined here is not so different from the classic time scale of the rocketpunk era. Heinlein, after his early (and wildly space-optimistic) Future History, got cagey about specific dates. But the interplanetary futures of Space Cadet or The Rolling Stones generally seem to be set around the 22nd century, and much the same for Clarke's hard SF, aside from books directly linked to 2001. The scale of things was closer to what my formula predicts for the 23rd century. But a few decades this way or that, or even 100 years, is nearly a quibble on the time scale of centuries.
The truth is that human expansion into the Solar System was always going to be gradual, because the Solar System is so big. 'Murricans should have been particular aware of this, because of the prolonged colonial prelude to our national experience. It was 115 years from Columbus to Jamestown, and another 168 years to the the Declaration of Independence. On the same time scale, starting from 1969, we might expect the founding of Luna Base in 2084 and the inevitable Revolt of the Colonies in 2252.
Viewed in large historical perspective our space progress is just about on schedule.
Image of proposed HOPE Callisto mission ship via Atomic Rockets.
Related posts: I discussed our rate of progress on the 39th anniversary of Apollo.