Placeholder, SPQS Universe

The Science of Placeholder, Pt.3

As promised, today’s post will focus on legitimate and speculative (plausible, albeit beyond our current capabilities) methods of creating ‘artificial gravity.’  There are actually very few options, so for the SPQS Universe, I settled on two primary approaches: the sloppy and cheap way, which civilians and research vessels are stuck with, and the right way, which only military and luxury vessels/stations can afford.  Although, it should be stated up-front that “the right way” isn’t really ‘artificial gravity’ at all—because, technically speaking of course, ‘artificial gravity’ implies using a different force to achieve the impression of gravity where there is little to none (microgravity, or micrograv for short).

 

(Spoiler Alert!  The rest of this post discusses technical details of Placeholder’s plot and primary characters.)

Artificial Gravity:

The most obvious and most successful methods for creating artificial gravity today are Acceleration and Rotation; for a spaceship, of course, both come with problems.

For artificial gravity that is really acceleration, that requires the ship to be constantly accelerating at 1g or less for the duration of the trip through space in order to provide a constant artificial gravity; that may be okay for a ship with say, a nuclear pulse propulsion rocket like the SFS Fulgora in Placeholder, but a chemical rocket can’t carry enough fuel to maintain that acceleration for long (and a fusion or antimatter-catalyzed rocket would be total overkill for a civilian crew).  The fact that in any human-crewed space journey, the first half is accelerating towards the destination, and the second half is ‘decelerating’ (ie., accelerating away from the destination to reduce velocity enough to bring the ship into orbit around the desired planet), is actually irrelevant—there will be a brief pause where microgravity returns as acceleration stops and the ship is spun around its central axis to point the rocket at the destination to begin deceleration.  Thus, artificial gravity resumes as before.  Of course, a constant acceleration of 1g (or more) implies an interstellar journey and a generational ship.  Thus, relying on it is limited to specific cases where it would be most appropriate.

Ships and Space Stations that have rotating sections to achieve artificial gravity are a fairly common staple of near-future sci-fi, and are generally included in current proposals for civilian space habitation and tourism.  It’s entirely feasible technology, assuming of course anyone is actually willing to pay to send all the necessary components up to space.  Since right now, our only means of achieving escape velocity is through chemical rockets with strict payload restrictions, it is ultimately only the costs that are prohibitive.  But once we achieve construction of a rocket that has the same high specific-impulse of nuclear pulse propulsion without the radioactive fallout (ie., fusion or antimatter rockets), or something even better like a space elevator or magnetic propulsion, such cost prohibitions will disappear.  The only other catch with rotational artificial gravity is the need for either a counterweight, or an even multiple of rings with half going one way, and half going the other.  In Placeholder, I combined both approaches; one large habitation ring, one small medical ring, a rotating quarantine bay, and a short counterweight.  I also designed the rotating sections so that they could turn on a secondary axis.  Thus, when the SFS Fulgora was under acceleration, the ring rotation could be shut down, and the floors could be turned towards the aft of the ship, so that the artificial gravity was always pointing in (roughly) the same direction.  Naturally I made the mechanisms in the ship a little slow, so that artificial gravity would curve up the aft wall a little before settling back level to the floor of the habitation ring.  It gave it more of a nautical feel.

 

Artificially-produced True Gravity:

The other dominant form of “artificial gravity” mentioned in Placeholder is what the Military vessels and stations use.  Technically, it’s not really artificial gravity at all, it’s real gravity produced by artificial means instead of a large mass.  They use shaped graviton-emitters to establish a virtual centre of gravity that recreates 1g perfectly.  It could be set to reproduce any gravity of course, but other than high-gravity training, that would be of limited use.  Thanks to our evolution on this particular planet, our bodies will always inherently prefer our natural gravity.  Obviously, graviton emitters reproducing Earth-normal gravity creates a host of other interesting troubles—propulsion the least of them.  But that’s a problem for another book, because Konrad Schreiber had no direct experience with them.

Now, in order to create a graviton-emitter, one would first have to prove that the quantum of gravity exists; searches are underway at several of the world’s high-energy supercolliders, but so far, neither the graviton nor the Higg’s boson has been discovered.  In my future history, I decided to take a pretty dangerous leap.  Some might consider it irresponsible even.  But nonetheless, I felt confident in saying that both the Higg’s boson and the graviton had been discovered, and furthermore, they were connected.  (The following statement isn’t scientific, it is pure speculation on my part and could very well be coming from a mistaken understanding of the standard model)  It seemed to me, that if the Higg’s boson predicted by the Standard Model is real, and it is in fact responsible for matter having mass, then either the graviton must be a decay product of the Higg’s boson, or the Higg’s boson is an intermediary in the exchange of gravitons.  After all, where there is mass, there is gravity; and while other forces may be able to reproduce certain effects of gravity, they are still not gravity.  But masses always attract each other, unless another stronger force, such as electromagnetism, overpowers that attraction.  The Large Hadron Collider is one of the particle accelerators that is supposed to produce a Higg’s boson (if it even exists).  As I understand it, if the LHC fails to produce a Higg’s boson, then the Standard Model is also going to be considered a failure.  I suppose we’ll have to wait and see.  They can only test one energy range at a time, and there are still many, many more to go through.  Either way, we can expect to have a definitive answer within our lifetime.

If existence of the Higg’s boson and graviton can be proven, it will only be by either detecting them in nature or producing one artificially.  And amusingly enough, it’s a lot easier to make one artificially then to just go out and find one.  You wouldn’t think so—gravity is everywhere around us, inside us, permeating every dimension of spacetime (however many it has).  But apparently, for some very good technical reasons, gravitons cannot be directly detected on Earth.  We’ve got to build a graviton detector in space, and nobody is going to do that until we know exactly what we’re looking for and have a way to find it.  In Placeholder, all that has already happened and is old news.  Both bosons were produced artificially, detected within a particle accelerator, and then detected directly in nature. Since to even detect it in the first place, it had to be produced artificially, the large-scale production of gravitons for true gravity on a spaceship or station is then only a matter of refinement.  First, make the process as efficient as possible, and then find a reliable way to power it.

 

And I think that about covers it.  Because of the particular modifications I made to current rotational artificial gravity system proposals specifically for the SFS Fulgora, I had Konrad cover the subject in gross detail.  And like I said, the detailed application of graviton-emitters will be covered in another story, where it is actually a fundamental part of the story.

For my next entry, I will skip past the molecular rearrangement technology (since it plays such a small part in the story), to nuclear power and propulsion in space.  And due to the current tragedy in Japan, which makes the timing of my novel seem somewhat poor in taste, it is a subject I should deal with immediately.

— the Phoeron

Advertisements