Perhaps some ideas are too tempting to dream about, such that the idea gets people stuck. Dreamers visit the idea, they find it inviting, so they continue to pursue it in their original dreamlike state. In modern discourse among educated people, a particular kind shiny idea has become something of a trap - the idea of a grand monument that delivers people and materials into space.
In my vernacular, this is a Launch Assist System (LAS for short occasionally). The “system” in this name is a subtle nod to the difference from modern day rocketry. These aren’t vehicles, these are systems that deliver things into space. The most popular idea, by far, is that of the space elevator.
There are no shortage of other idea that may be extraordinarily different in character, but still almost identical in function. Going by my own memory of concepts, I’ll just list broad categories here in order of what I hear about most:
- Tether assist systems
- Launchers (ranging from space guns to takeoff tracks)
- Buoyancy assisted platforms and vehicles
I’m excluding air-breathing assist vehicles, because there are numerous designs that are extremely well proven and sometimes even profitable. For this post, my interest is in the transformative and outright crazy ideas.
It wouldn’t be hard to point to concepts that are just plain whacko. Under the category of launchers, we have the slingatron:
New Reusable Launcher Could Slingshot Probes to Space
A new kind of reusable launch system could make hurling satellites, spacecraft and other payloads into space much less…
In a historical sense, this was never much more than anything beyond a sensational meme in the tech new and blogosphere. The concept solved absolutely none of the problems associated with space guns, and introduced so many new novel problems unique to it.
While some space guns are genuinely viable technically, they could only hope to occupy a tremendously niche market of sending commodity materials, for which the distribution part of the equation is decades in coming.
Airship-to-orbit is so creative that they’ve forced the creation of a new category, almost entirely to themselves. Buoyancy, however, is still suggested as a means to have morning platforms at ultra-high altitudes for launches, which again, is technically arguable but instantly economically self-defeating.
Tethers and Unicorns
After giving some lip-service to the full range of what’s possible, we need to recognize that the real popularity lies in tethers, and even more specifically, in the space elevator families.
Space elevators are almost the picture-perfect unicorn technology. It is quite heavily advocated by a large mass of disciples, and yet, it will basically never ever make sense. An Earth space elevator is an idea so bad on a cosmic scale, the only thing notable about it is that someone ever seriously advocated for it in the first place. Even if you could muster the materials to create it (purely through the magic of the “sake of argument”), it would yield a system painstakingly slow and brittle compared to just about any available alternative.
Genuinely educated people who write about this stuff spend probably a majority of their time shooting down other ideas by the more brazen of its advocates. Such was the case for the following about tethers around Mars orbit. The gravity of Mars would make a full “stationary” space elevator astronomically easier to build than one on Earth, but it turns out that it’s still not a good idea if you adhere to any degree of loyalty to what is possible with real engineering.
Zylon Mars Elevator
Mars Elevator With Conventional Materials Mars spins nearly the same rate as earth (about a 24.62 hour day). Mars has…
Use of a Phobos tether is pointed out as the obviously superior alternative, and on this point the author is tremendously correct. There could be a number of advantages to the gravitational environment around Phobos. For instance, the ability to connect a surface station to a zero-gravity location could be valuable for a large number of reasons in addition to just being cool. The arguments around the kinetic merit of assisting travel of visiting spaceships is something that I find a little less convincing, just because I’m not convinced of any demand for it, although the technical aspects are sound.
Your Problem is Atoms
The real world is not made of rainbows and magic, it is made of atomic matter.
We don’t often hear anyone advocating that fusion power would be easier if we could just put it in some kind of “ordinary” box, provided that material science comes up with something strong enough. The only thing different about space elevators is that the requirements lie sufficiently close to the margins of what is possible with atomic matter that people have decided that they would rather not let the idea die.
From the very day that writers started imagining humans traveling into space, the details of Launch Assist Systems were incorrectly projected and horribly wrong. In one book, Jules Verne imagined both a gun-type launcher, and proved that he understood neither basic ballistic calculations or orbital mechanics. Yet, that starry-eyed book had a relatively substantial impact on society and the human psyche about space exploration.
Personally, I have become increasingly polarized against any use of space tethers for momentum-related purposes. Don’t get me wrong, I still see tremendous value in space tethers for other, more ancillary, reasons.
What’s more frustrating than the overwhelming sea of voices getting this stuff wrong are the occasional voices that are getting some components right, and my burning desire for someday a convergence happening to make these related areas an actual science of some type. Correctness in this area seems to almost always go hand-in-hand with humility, and the following little-known site is quite abundant with both humility and correctness on topics that are quite often entirely novel in history:
Some ways out of our atom-based cage are genuinely possible. For extremely large momentum transfers, enormous energies relative to the chemical energies in the payload are necessary. In addition to this fact, reusable Launch Assist infrastructure would almost invariably be dramatically larger than those payloads, by a factor of a human to a house or more.
But if you take a step back and accept those realities, it seems completely comfortable within our modern technological bubble. We don’t have a problem riding in vehicles with sufficient power to obviously dismember us. We will someday not have a problem entering a ride controlled by a machine with enough energy to vaporize our very atoms.
It’s not a question of “if”, but “how” and “when” these things will come to be built in the future. With all this said, the sooner we can all come to terms with the correct constraints of these systems must exist within, the better.