Longtime readers of this blog know that I am somewhat heretical regarding the human future in space. As I first argued a couple of years ago, outer space is profoundly unlike the New World - such an evocative phrase! - that Europeans encountered five centuries ago (and proceeded to loot and colonize).
This heresy has come up in, and spilled across, a couple of recent comment threads, especially the one for the previous post. (And yes, it was nearly three weeks ago. What can I say? June sort of slipped through my fingers.) As heresies go it raises enough interesting questions to deserve a front page post.
Space is, for one thing, a great deal more difficult to reach than the New World was. Europe's worldwide maritime expansion closely followed a tech revolution, development of the full-rigged ship. But this new technology could be and was employed off-the-shelf for oceanic missions. The Santa Maria was an ordinary freighter. If we could reach Mars aboard second-hand jetliners we would already have gone there.
And once you do get there, nothing in space is remotely conducive to human habitation. The traditional driver of settlement colonization (as distinct from strictly political colonization) has been cheap land. But there is no 'land' in space at all, at any rate in the Solar System. You have to manufacture it, building a hab or a sealed dome, then providing a working ecosystem inside.
It would be many times easier to build luxury condominium developments in Antarctica, or on the continental shelf.
Now, compare all of this to the Solar System of Heinlein's juveniles, where a lot of us got our basic conception of the space future. The space technology made a couple of iffy assumptions. Nuclear thermal drive was not only technically capable of lifting ships into orbit, but socially and politically acceptable as well. Moreover, the chemfuel alternative involved some very convenient magitech, namely monatomic hydrogen, stabilized by means Heinlein never went into.
If you wonder why our real world space tech is so much less convenient, those are sufficient reasons.
But even more than this, Heinlein's Solar System made Venus a 'shirtsleeves' habitable planet, while Mars required no more - or so it seemed - than a mask type breather device. (Heinlein's juveniles do not strictly form a single future history, and details vary, but they portray a broadly consistent future.)
Heinlein's Solar System also had at least two living extraterrestrial civilizations, on Venus and Mars, the local inhabitants having different characteristics in different stories. (The blue-elf Venusians in Space Patrol are entirely unlike the dragons in Between Planets.)
I belabor all of this because Heinlein's Solar System (in particular) had such an enormous impact on what we expect out of the human future in space. In the first years of space exploration we found out that the real Solar System is a very different place, but we have tended to hold onto the old tropes as far as possible, even when reconfiguring them - as in envisioning orbital habs in place of domed surface colonies.
Much of this is for the sake of Romance, i.e. stories. But space discussion often blurs story settings with 'real' possible futures. This blog is particularly guilty of doing so, and quite deliberately so. Space is no fantasy world, a creation of pure imagination. More than 500 people have gone there, and our machines have traveled across the Solar System.
Human interplanetary missions are clearly possible, to the point where we can discuss their architecture in considerable detail. They are merely horrendously expensive, to the point where there is no particular eagerness to pony up sufficient funds. Permanent human habitation in deep space is technically much iffier, particularly with respect to self-contained ecosystems. But it is surely possible, even without such ecosystems. Again, colonizing space is merely, with foreseeable tech, horrendously expensive.
And there is no obvious reason for doing it except that living in space would be Really Cool. For which people will spend a lot of money, but sometimes cool is just not affordable.
On the other hand, the future - not just the plausible midfuture I talk about here - is a Really Long Time. For that reason, saying we will never do something is the iffiest proposition of all. Who can say what our descendants might be doing in the year 22,011, or 2,002,011?
But in the next few hundred years, absent unforeseen breakthroughs in technology, we are more constrained. We might have true space colonies by 2211, but I think it is unlikely, and also unnecessary. Much more likely we will still be exploring space, mainly with machines though sometimes sending people, and perhaps setting up outposts in a few locations.
As a setting for space opera such a future is deficient, but it is a natural way for humans, at something like our techlevel, to come to grips with space.
For more contrarian argument, see author Jeffrey F. Bell. On the technical substance I tend to agree with him, though I would be a bit less quick to throw around 'impossible'. That said, Bell seems to have a remarkably well developed sense of martyrdom. No one ever expects the Spanish Inquisition, but space heresy is not exactly like getting on the wrong side of theological disputes during the 16th century.
Related Post: A Solar System For This Century.
The image of Archbishop Cramner being burned at the stake comes from a website about Anne Boleyn.
Monday, June 27, 2011
Tuesday, June 7, 2011
This used-car dealership on mid Market St. has intrigued and amused me since moving to Babylon by the Bay.
Since ordinary batteries involve ions, I suppose the Chevy Volt or even a Prius could be said to use a form of ion propulsion, but how many people associate electric cars with 'ions'? In any case there is no indication that this place specializes in electric cars. Their website does not explain the name, but I can only guess that the name is intended to evoke ion propulsion for spacecraft.
The logo - for a business that touts itself as the bay area's 'newest car dealership' - sort of goes along with that connotation, I think. Doesn't it have a bit of Zeerust retro flavor?
Ion drive, in fact, is probably the only high specific impulse that qualifies as a trope, in the (correct) sense used by the Evil Website. A broad cross-section of people, not just geeks, have at least some vague sense that ion drive is an advanced and futuristic space drive, yet at the same time a 'real' one, not pure sci-fi jive. Perhaps its status was confirmed by Trek, either The Wrath of Khan or its TOS progenitor episode, in which ion drive was characterized as an archaic technology.
Nuclear-thermal propulsion, AKA atomic rockets, do not quite qualify as a high specific impulse drive, its classic form outperforming chemfuel by a modest factor of two or three. Fusion drive, much debated and belated at websites like this one, does not seem to me to have quite made the jump from geekdom to the broader public. The same applies to generic torch drive. Possibly Avatar will promote antimatter drive to trope status; only time will tell.
Compared to these latecomers, ion propulsion has an enormous headstart. Somewhat remarkably, Robert Goddard considered ion propulsion more than a century ago, in 1906. Konstantin Tsiolkovsky published on the subject in 1911 while Goddard performed actual laboratory experiments in 1916-17.
The rocketpunk-era books I read as a kid about Our Future in Space almost always mentioned ion drive, generally in the context of what I now call the plausible midfuture. I recall one book with great illustrations that portrayed an ion drive ship under the heading To the Stars. The next page had a photon-drive ship, To the Galaxies. The temporal implications of intergalactic STL travel were left undiscussed.
I don't have any specific recollection of ion propulsion in rocketpunk-era SF. Heinlein had no interest in space drives that lacked bone-jarring acceleration; his propulsion sequence thus went from nuke thermal to Ortega's mass-conversion torch to the unabashedly magitech Horst-Milne-Conrad impellor.
Clarke also never specifically mentioned ion drive, at least that I recall. He was usually rather cagey about deep space propulsion details, though I often got the impression that some sort of electric drive was implied.
Therein, of course, lies the rub. As I understand it, ion thrusters are in fact not suitable for deep space propulsion of large, human-carrying spacecraft. Their thrust is very low, even by high-ISP standards, and apparently the thrusters cannot readily be scaled up. Ion propulsion is now in service, used by the Dawn probe among others, but there are unlikely ever to be ion-drive ships.
But in trope terms - in the mind of the popular culture - ion drive is synonymous with electric space propulsion in general. Technologies such as VASIMR, while they do involve ionized plasmas, are not 'ion drive' in the strictly technical sense. But in some broader cultural sense they are indeed ion drives, technical details be damned. If it emits a faint blue or purple glow, produces gentle but steady thrust for days, weeks, months on end, it fits the cultural vision of ion drive.
Though I wouldn't recommend it for Bay Area freeways.
The image was taken from my el cheapo ('free') smartphone while riding a vehicle with electric drive: the F Market streetcar.
Posted by Rick at 6/07/2011 11:46:00 AM