My book TRACER isn’t hard scifi. It’s not going to bombard you with equations or make you wrap your head around string theory. Chiefly, it asks you be OK with the concepts of fistfights and explosions and parkour in space. And severed eyeballs. Can’t forget them.

But that doesn’t mean I didn’t want the science to be solid. Here’s how I did it.

Artificial gravity – or not



TRACER is set on a massive space station, Outer Earth. The station floats three hundred miles above the planet. The damn thing is big – it’s a huge ring, eighteen mile circumference, six mile diameter. There’s a fusion power core floating at the centre of the ring, connected to the body by two large spokes.

When I was writing TRACER, I faced an immediate problem: gravity. The effects of gravity on the human body over the long term are…not good. And my station inhabitants had been up there for over a hundred years!

Oh sure, I could have cooked up some gravity generator mumbo jumbo, but I figured I could do better than that. There had to be a way to get the gravity on my station to Earth-normal.

Enter Barnaby Osborne, a genuine rocket scientist at Kingston University in South London. He very graciously allowed me to come down to his lab, and gently suggested ways in which my sucky space station design could be improved. Including the gravity problem.

Ever seen one of these?



That’s centrifugal force keeping those people on the wall. The faster the spin, the more they stick.

Now imagine that funfair ride is massive by an order of magnitude. Imagine that those people stay the same size. Not only would they be able to actually walk around on the wall, but they’d be able to do it while the station was moving at a very slow rotation rate.

Because that was the beauty of it. To get gravity on its inner surface to 1G – earth normal – a small ring has to spin very, very fast, and severely curtails the movement of the people inside it. But a big object? One, say, eighteen miles in circumference? It doesn’t have to spin fast at all. That’s the beauty of it. You get a perfectly liveable environment which doesn’t impact the human bodies living in it.

Ah, but what about the coriolis effect, I hear some of you say? Well firstly, you people are smart-asses. And secondly, that’s true – it’s a problem with spinning structures, defined as:

deflection of moving objects when the motion is described relative to a rotating reference frame. In a reference frame with clockwise rotation, the deflection is to the left of the motion of the object; in one with counter-clockwise rotation, the deflection is to the right. (Wikipedia – yes, I know, so sue me)

In other words, if someone on that fairground ride chucked a ball at the other side, the ball would appear to curve. Similarly, someone standing with their feet on the wall and their head closer to the centre would feel differing gravitational forces on their head and feet.

Again – this is something that’s only noticeable in smaller spinning structures, where the distances and relative size of the objects inside accentuate the effect. But if the ring is massive, the effect ceases to be a problem (imagine an ant walking around that spinning fairground ride – think it feels crazy gravitational effects? Nope. Ant be chilling).

There’s a scene in the book where a character crosses to the fusion core, moving to the centre of the ring – and there, the effect becomes noticeable. At that point, it’s not a story problem – just another fun obstacle for her to overcome. She probably isn’t best pleased with me, but fuck it.


Quit bugging me



How do you feed a million-plus people in an enclosed environment?

Sure, you can grow veggies – and the folks in my station do. But that creates space problems in and of itself. You could create genetically-modified foods, like lab-grown meat for protein, but it depends on scarce resources outside of the ones used for growing veggies, like recycled water. Fortunately, I found a better solution: bugs.

They are the perfect solution for this type of problem. Large numbers of them can be bred in a small space. They require far fewer resources – important on a space station. They are packed full of tasty nutrients and proteins – well, maybe not tasty per se, but you get the idea. It’s kind of amazing we don’t eat more of them.

I spoke to Marcel Dicke, an entomologist at the University of Wageningen in the Netherlands, to confirm this. He’s the reason the people on Outer Earth nom tasty fried beetles, chug down silkworm paste, and coat their mashed potatoes with lovely cricket powder. Yum.


Getting warmer



Here’s a really, really big problem with space stations that almost every science fiction writer forgets. They get hot.

I mean, really hot. Bang a large number of people into an enclosed system, or even a small number, and they kick off a huge amount of body heat. Unless I had a way to dissipate all that heat, life onboard Outer Earth would be singularly unpleasant.

Answer: ammonia.

Expanded answer: a giant cooling system of ammonia-carrying pipes, blanketing Outer Earth like a nervous system. Ammonia is a fantastic chemical for transferring heat. The pipes travel across huge fins on the station’s hull, exposing the heat-carrying ammonia to the freezing vacuum, and sending all that heat into space.

Which begs the question: what happens when a psychopath shuts the pipes down? To find out, you’ll need to read the book.





How do you power the station?

Nuclear fusion – the same principle that powers the sun. It has a crap-ton of advantages that made it perfect for my story: it’s clean, it can be easily fuelled (the tritium required for this can actually be ‘bred’ in the reactor), it has little to no nuclear waste products, and it’s very easy to control.

The downside: we don’t have the technology to build an effective one yet. If we could, then all this debate about nuclear power plants and remaining fossil fuels would be so much fluff in the wind. On the surface, that precluded me from using it on Outer Earth.

Except: no. It doesn’t. Outer Earth is set in the future. Why the hell shouldn’t I have a fusion reactor? I’m not breaking the laws of physics. I’m not creating something that defies belief. I’m just making a point that we’re advanced enough to have a reactor like this now. 

Big-time thanks to Chris Warrick, of the Culham Centre for Fusion Energy, who helped me work out some of the kinks in my reactor core…


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