Space dogfights, what is down in a spacecraft, and upside-down moonwalking

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December 25, 2014
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Space dogfights, what is down in a spacecraft, and upside-down moonwalking

I received some very interesting comments today from Hans. Thanks, Hans 🙂 So that I could share more easily with everyone, I’ve put them into this post. Let’s have some debate!


First up we have space dogfighting.

Here’s Hans:

IMHO I think that banking in space only makes you an easy target. Turn 90 degrees and accelerate hard to change direction takes time, fuel and is too slow (while you’ll keep going forward ’cause you didn’t stop).

As I conceive a ship, it has thrusters all around its construction so you can roll, pitch, yaw but most important you can go up and down.

As I see a space battle, if you want to shake someone at your six, you turn 180 degrees, go up or down, pitch, fire at your pursuer, and brake hard (afterburner) so you can get at his tail. I agree that he can do the same.

Depending on the size of the ship you can have turrets (even in fighters) and fire at your pursuer while dodging him.


I think you make convincing points, Hans. Away from the gravity wells of planets and other large bodies, space is an unbounded three-dimensional battlefield. It’s difficult for us here on Earth to truly think that way because it isn’t how we personally experience the universe. Even if you’re a pilot of a fighter (airplane) then you are a lot more limited in what you can do with up and down compared with space (down is particularly limited in an airplane!).

One of the implications is that you can have thrusters pointing in several different directions. As Hans, says, if a hostile is on your six, you could swing around 180 degrees, apply main engines to brake rapidly, but, at the same time, move up (or indeed any direction you like perpendicular to the hostile’s heading).

One of the ships introduced in Marine Cadet (and we’ll see much more of them in later books) is the ‘Tactical Unit’. I don’t describe the propulsion system (maybe in a later book) but it takes some of Hans’s idea to its logical conclusion, because it is a spherical ship with a main propulsion unit at the centre of the ship that pivots around to line up with one of a score of exhaust ports. So, rather than turn the ship around to point the main engine mounted aft in a new direction, it’s just the engine in the centre that has to pivot, which it’s designed to do extremely rapidly. That makes turning quicker. Not much but maybe enough to give you an edge. Also, because you can’t see the central engine move from outside the ship, your course changes aren’t broadcast to the enemy (unlike the alternative: if your ship is pivoting around to point in a new direction, it’s clear you want to change vector).

I’m thinking a lot about space combat right now. There’s some ship-to-ship combat in Book2: Indigo Squad. There’s more in Book 3. And space fleet battles are the main background to Book 4 (and, yes, there will be space fighters). So this is a very useful discussion for me.

Back to Hans on gravity and direction inside the starship.

One comment about what is up and down in a ship in space: I agree that in open space there is no up or down but in a ship (or space station) it’s determined by its construction. I doubt that all equipment will turn 180 degrees to satisfy the concept. Can you imagine a bridge half in one side and the other half in the other?

Most of the second book is set on a ship called the Beowulf (in homage to the RPG I played in the 1970s called Traveller – Free Trader Beowulf is mentioned on the box.) The Beowulf’s design has a main engine mounted in the stern. When that’s running full blast, the crew experience down as being in the direction of the stern (aft). So all the compartments and connecting passageways and ladders etc. need to work when everything appears to be pulled down onto the aft bulkhead. For example, all the stations in CIC are fixed to that aft bulkhead. That orientation of CIC is permanent.

This is Free Trader Beowulf, calling anyone...  (Image by Marshall Stax)

This is Free Trader Beowulf, calling anyone… (Image by Marshall Stax)

Most of the time, the Beowulf isn’t accelerating, so is in zero-g. So the design has to cope with both pseudo-gravity from acceleration and zero-g. I had to think hard about my bar, for example. How to stop all the drink containers spilling or shattering when under acceleration, but how to make full use of the zero-g potential for recreation.

Hans had a point about a scene in Marine Cadet.

IMHO, keeping yourself upside down at the moon’s battle is not realistic but permissible as it’s a SF book. Why’s that? Simple: Despite moon’s size it has some gravity. i.e. earth’s moon has 1/6 earth’s gravity. If there was no gravity in the moon (described in the book), no one would be able to stay at the floor, hence those that were in the ceiling would be gently fall due the moon’s gravity.

You’re very generous 🙂  The Marines start off the books with cast off technology. You get a glimpse of the technology developed by civilizations 100s of thousands of years ahead of us. Although the tech level appears patchy to our characters. Here’s a quote from the beginning of Book3: Renegade Legion.

 In his Marine battlesuit, Arun could activate stealth mode, a technology so effective that sophisticated enemy targeting systems would be blind to him.

So why were the recon drones so noisy that he could hear them half a klick away?

Stealth-capable recon drones had to exist somewhere in the White Knight Equipment inventory. It was as if the Tactical Marine regiments on Tranquility had been equipped with unwanted leftovers discovered at the back of a dusty store cupboard.

If the Human Legion was to survive and prosper, Arun would put a priority on sourcing better equipment.

The battlesuit technology is one of the more mysterious technologies. No one Arun knows understands how it works in the first book. He meets someone who is beginning to in the second. The acceleration available to the suit propulsion is inversely proportional to the strength of the gravity field you’re in. On a planet like Earth you get an assisted hop. In deep space the suit has the potential to accelerate so fast that it could pulp anyone inside the suit. On a moon that is approximately 1/6 Earth gravity (as with Earth’s moon) then at full blast you can play tricks such as walking on the ceiling. In the second book the Marines board a ship where their suit motors fail because they’re in a gravity field. That confuses the hell out of their scientists J


Thanks again to Hans and everyone else for your comments. And thanks to everyone whose support has made the first book a bestseller. For those who have enquired about the second book, it is written and being prepared for launch. I can’t give a date but it will be published January 2015, probably mid-Jan.




  1. ruopp says:

    Hi Tim,

    I’m not an engineer (just an old IT dinosaur) but I see some serious problems with your Tactical Unit idea. It’s not about it’s shape (Sphere), R.L. Akers wrote a trilogy (Prometheus) that uses the same concept, Raymond L. Weil too.

    The problem is that once you want to rotate the engine you’ll have to turn it off, rotate and turn it on again and that takes time. If you don’t turn off the engine while rotating you gonna fry the ship and if you turn it off and on again it will take time to do both. I see it’s more a liability than an advantage.

    One option I see is to have a circular exhaust chamber connected to all ports around the ship and open and close the ones you want to use. Then you’ll only have to deal with temperature containment.

    Both ideas won’t avoid the enemy to detect your intention to change vector. Exhaust system expel hot gases and for sure any ship has heat sensors. Once you cut exhaust from one port and open another one the enemy will notice at once. And the worst is that he will perceive it before you’re able to apply your maneuver. Why’s that? Because any enemy worth its name will have intelligence of your ship’s construction and methods to counter your advantages.

    Another problem I see is that instead of rotating the ship and show fresh shields to the enemy, the same side will be exposed to more hits. And worse you’ll have many more critical target points so the enemy can destroy your ship (exhaust ports) more easily.

    In fact there is no advantage to this system (or ship shape). If the pursuer’s ship has powerful maneuver thrusters he can match your new vector and will have the advantage to fly parallel to you with fresh shields (starboard) while you’ll show him the same side. To show him another side you’ll have to rotate the sphere (same problem with no matter what shape your ship is).

    Another problem I see with sphere constructions and your idea in particular is that usable space is not optimal. There is little space for weapons emplacements due the engine system (heat is a serious problem to weapons system). Insulation will make the ship a big target if you compare with other constructions with the same capabilities. Imagine you’re behind my fighter and I turn 180 and fire at the exhaust port that is just in front of me? What will happen if your shields are battered for so long?

    In my opinion dogfighting in space with fighters is not feasible. Why’s that? Simple: No fighter has enough fuel to deal with it. Think about the following scenery: Your fighter is being pursued by another fighter (you’re going forward). You turn port and accelerate (adding another momentum). Now you’re going forward and port (you didn’t stop before change course). Then you have to go up. Now you’re going forward, port and up while dodging the fighter behind you. Let’s say you were able to destroy your pursuer, how much fuel will you need to stop going forward, port and up and then head back to your carrier? Let’s not forget that once you achieve these three momentums (forward, port and up) if you want to change again you’ll have to stop one of them and then accelerate again. Now think how much fuel these maneuvers takes.

    As you pointed out Tim, it’s hard to people realize that in space (without air resistance to break your momentum) you have to spend the same amount of fuel to break your movement.

    Having any other propulsion system that let you change vectors breaking your momentum is possible in any SF book or film (that’s why it’s called “Fiction”). Some authors deal with science more seriously explaining the hard facts and why they choose to follow that path. Others prefer to deal with science as a secondary matter and concentrate in the plot and personages. Others prefer to do both.

    Personally I take the best of any book, I try to understand which focus the author chose (science, plot, and personages). As Tim pointed out in another post, some SF films are just a bad science joke as some books too but hey what about the plot and the personages? Were they good? Did you have a good time reading the book or watching the film?

    As I see, Tim has chosen a middle term path: good personages, good plot and middle term technology, some quite understandable by our science knowledge (railguns, etc) others not (railguns carbines, battle suites, all with alien tech). Personally I like that, others authors are doing the same as you can see in the new series from Raymond Weil. Before someone point out that railguns carbines are explained by science I have to say that our actual technology can’t produce one, why? Simple: we do not have the technology to produce a portable power source to fit in a carbine (well maybe aliens have). Jay Allan came with an interesting solution to this problem: The power suit has a reactor in its back and the carbine is connected to the power suite.

    Finally, my intention is not to discourage you Tim, ‘au contraire’, your plot and personages are really good. Explain the tech is secondary. Alien tech can do things that our knowledge will be unable to explain and this is SF. Keep your good work. 🙂

    Happy New Year


    • timctaylor says:

      Thanks Hans. I hope you didn’t wake up with too bad a hangover this morning 🙂

      You are absolutely right about my philosophy behind writing these books. I want to at least try to consider the physics and engineering reality in my setting. But that’s in service to trying to tell a good story.

      You’ve given me a lot to think about with spherical ships. I feel a blog post coming on to explain the Tactical Units! But that must wait until I’ve completed the final layout for Indigo Squad, the second book.

      Thanks again for all your comments.

      Oh, and I want to point out that I am also an IT dinosaur, so we maybe think a little alike. I cut my first commercial code in 1988 when I was working for a chemical company.


  2. Hans says:

    Hi Tim,

    Hell, yeah, I woke up with a nice headache but nothing that some tomato juice with lots of tabasco can’t deal with. Hopefully I still have today and all the weekend to deal with it. 🙂

    Oh, and I want to point out that I am also an IT dinosaur, so we maybe think a little alike. I cut my first commercial code in 1988 when I was working for a chemical company.

    I started a little bit earlier, in 1982, working for a software house that developed system for different clients with different activities (press, transportation companies, etc.) Good old times. 🙂

    IMHO, I think we think a lot more alike than you can imagine. Both of us are driven by logic (its part of any IT pro). Many times I find myself writing algorithms in my mind to solve real life problems. I can say I have become addicted to this stuff.

    About the TU, you can simply use an alien tech to power it, which means you don’t have to use explainable tech. Let’s not forget that most of the tech in your book is of alien origin (White Knights).

    My other comment was just to point out that with our knowledge this system is not really an advantage. Why can’t alien tech have a system that can nullify your momentum and change vector in seconds? Much like FTL travel and other techs we have in SF stories. The best in SF books is that not all has to be explained by our actual science knowledge.


  3. SGT Mike says:

    Hans, I believe the term for what you describe is ‘Suspension of Disbelief’. Well said though, much better than my college English professors ever did!!

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