Why do ships in Battlestar Galactica constantly run their main engines?

Question

In the 2004 reboot of Battlestar Galactica, many of the spaceships are shown with their engines on for extended periods of time. In space, there is no air resistance to compensate against with thrust, so why have the engines firing unless you are accelerating/decelerating or maneuvering?

This is especially evident with the vipers during gunfights. It would seem that having their main engines constantly on would cause them to accelerate to very high speeds.

There is a point where Boomer mentions that her raptor should have enough inertia to reach her destination, implying that without enough the ship would stop short of the destination.

Is there ever any explanation of this either in-universe or during an interview? Or is this just done for visual effect?

Answer 1

Because it looks awesome.

Science fiction is about wonder and awe as much as it's about telling a scientifically-based story. Not having engines always firing is accurate, but it confuses viewers, who know how airplanes look when they work, and wastes the wonderful opportunity for the awesome visual effect.

They're asking for you to suspend your disbelief so they can dazzle and excite you.

EDIT: some answerers have been discussing real orbit-mechanical reasons why you might run your engines for extended periods of time. Those are fun and fascinating discussions for the real world, and I encourage you to pursue them. However, all of them are voided (if you pardon the pun) by the existence of FTL. Almost, if not all, crafts that go any distance in the show do so under FTL power, so the real strategies such as acceleration-deceleration trips aren't relevant.

Answer 2

I've also been wondering about this but I have thought that it could be in case they need some rapid acceleration in order to get away from another object its safer to have the engines at 1% thrust at all times. For example say the Cylons suddenly appear in Battlestar, then it will be a lot slower to turn on the engine AND THEN increase thrust rather than just increasing thrust from 1% to 100%. I assume if it is constantly at 1% that they counter the constant 1% thrust every 12 hours with a burst of reverse thrust.

Answer 3

Because the audience expects a visual indication of speed

Your average sci fi viewer isn't going to look at a spaceship in deep space and simply assume it is in motion, especially not assuming that the object is moving really fast relatively speaking - space lacks the visual cues we are use to seeing (clouds, landscapes, by default other vehicles).

It's hard to illustrate, but if you peruse the following compilation of fight scenes:

You'll see that the show uses the following tricks to convey speed:

1. Speed relative to other ships. For instance, fighters moving past larger vessels
2. Ships clearly moving past interstellar debris/galaxies/etc
3. Camera angles and perspectives (IE a first person view in flight, motion blur, sweeping shots)

And of course:

• Visible engine thrust

Note that the engines aren't always blaring at full thrust. Sometimes you can clearly see that the engines are blasting - usually to indicate they are charging into battles, and other times they're a softer blue glow which helps indicate that they aren't a static unmoving object.

As others have noted, the science on this isn't decidedly against Galactica. It is, after all, a show where the fleet is fleeing about 90% of the time - so they aren't necessarily always trying to get somewhere efficiently as much as they are just trying to get away.

Answer 4

It could be how they generate their artificial gravity. The MCRN Donnager from the TV show The Expanse uses this technique. The decks are alligned perpendicular to the center axis that runs the lenght of the ship so that forward thrust generates the artificial gravity.

Let's not forget that they are constantly under threat of the Cylons that pursue them so it could just be the mentality of "we stop, we die."

Answer 5

In many sci-fi franchises the engines provide thrust to get to the destination quicker. Although no thrust is needed to maintain a speed in space, the travelling time can be cut down by using thrust to accelerate to approximately halfway then using reverse thrust to slow down for the same amount of time. That would, of course, depend on the reverse thrust being the same as the forward thrust. Not many spacecraft in BSG have big old engines on the FRONT, after all. Maybe there's some form of thrust vectoring in play on the main engines.

It's worth highlighting that there's no real upper limit to speed of an object in motion in a vacuum, and continually applying thrust accelerates a ship according to the engine power levels. Galactica, being the only military ship in the "ragtag fleet", probably has the most powerful engines and runs them at a fraction of max output to allow the others to keep up with it and still be able to decelerate at the end of the voyage.

Answer 6

You answered the question within the question.

"having their main engines constantly on would cause them to accelerate to very high speeds."

The entire MacGuffin Engine of the series is that they are:

1. Being chased by Cylons
2. Going somewhere as fast as possible

The only time you see them shut everything off is because they HAVE to (or when they're in orbit). For maintenance repairs, for damage repairs. And then they mumble & stare at each other in fear, hoping that nothing happens while their engines are down.

Compared to many other Sci-fi, Battlestar does a lot of things right. You see the venting of the Vipers for manuvering. You see those with engine damage go streaking off in whatever random direction they were going prior the engine stopping working. You miscalculate the FTL jump, you land inside a mountain.

The initial encounter of the New Vipers vs the Raiders, you see the vipers 'parking' in lines, using their vents to stay "upright"... and when they get hacked, they start slowly spinning, as the vents no longer maneuver them back into place. In every attack from the Battlestar, the vipers have to keep their engines on to not only get from point A to B, but also to get rid of the momentum they gained from the ship, and furthermore to chase down the enemy raiders. Yes - there is something ridiculous about dogfighting in space, but they also touch on that by using projectile weapons of various levels of dumbness. The reasoning of the dumbness & use of 'ancient' weapons at that level of techology is due to the inability to network anything - any smart missiles shot at the Cylons would simply be hacked and turned around against the humans (although you'd think the Cylons would use them... although technically the raiders ARE smart weapons?).

Although there is no mention of conservation of momentum on FTL Jumps - FTL in Battlestar is a point-to-point Teleportation similar to Battlefield Earth, where objects are simply moved, rather than travelling through warped space which WOULD have conservation of momentum, and require deceleration & "internal dampeners". Also, if each FTL jump obliterated all momentum up to that point, that would also explain why the fleet's engines seem to be always running - each Jump requires them to start from 0, and build up the acceleration again.

Answer 7

In real life, as in not in movies, the ideal way to go from A to B in space is to constantly accelerate for 1/2 the journey and then constantly decelerate for the other 1/2. The only reason you don't do this is if you can't afford this (you don't/can't carry enough fuel).

So, assuming advanced technology (with the luxury of not running out of fuel for the duration of the journey) you would never want to turn off your engines and constantly accelerate all the way. This is the only logical strategy if you want to minimize travel times.

In fact, if you do the math, not only would you not want to turn off your main engines but you'd want to run them at 100% all the time.

So, in fact having the engines constantly on is not unrealistic, but very realistic assuming they have the fuel.

The only slightly unrealistic part is the battle scenes where Basestars and Battlestars are essentially stationary. Real slower-than-light space battles would most likely occur at very high speeds and long distances. Obviously if they show that on TV it would be less dramatic, because you wouldn't see much.

Also unrealistic is the concept of fighters in space. In space your speed (acceleration) is a function of how big your engines are. So fighters would be dismally slow compared to Battlestars, which means they'd be mostly useless. The moment they're launched the Battlestar would accelerate so much faster that they'd leave all the vipers behind. The only reason fighters are faster than aircraft carriers on Earth is due to friction. And there is no friction in space.

Answer 8

The engines are reaction-mass type engines. There is a large electrical field in the reaction chamber that sends the reaction mass out the nozzle to create locomotion. The electrical fields would always be on, and are powered by the generators on board the ship (which supply everything power on board, and are always on; they do not move the ship directly). The engines pump reaction mass (fuel) into the electrical field when acceleration is desired. Therefore, even when not accelerating, the engines will glow; when reaction mass is pumped into the engine you'll see the reaction mass ejecting out of the nozzle as visual "thrust."

The engines are always on, and glowing, but not always generating thrust.

I read that the Tylium is used in a fusion reactor, supporting the idea that the engines must be mass-reaction drives.

Answer 9

Just re-watching bsg and the sub-lightspeed engines thrusting also bugs me a bit. The suggestion that this is because it's what people expect is somewhat disproven by the fact that the cylon base stars don't even seem to have such engines although they do seem more space station like and therefore static.

It makes sense for the small craft, but Galactica itself and the fleet that follows don't seem to need such engines most of the time with the exception that sometimes they might need to manoeuvre closer to a planet or similar in a safer fashion than jumping can manage.