Thruster Propellant

In the Halo universe there are plenty of things that use thrusters. Aircraft, spacecraft, Mjolnir armor, jet packs, and so on. Now, good ol’ Newton’s third law of motion states that for every action there is an equal and opposite reaction. Which means that to go anywhere you need to push against something. Especially in the vacuum of space. This is the very principle that space travel is built on. This means that to travel anywhere in a vacuum, you have to eject mass. That’s why rocket fuel exists. This means that Pelicans, jet packs and whatnot need to eject mass, and need to have fuel. This fact isn’t very special, until you realize that a Pelican or long sword can make it from a planet’s surface to orbit and still have fuel left to adjust its orbit. The Pelican can even do this while carrying tanks or heavy cargo. Even in The Fall of Reach, when Keyes does his “Keyes Loop” manuever, he fires a nuclear missile in the opposite orbital direction of the ship he intends to hit, which means that the missile had the propellant to completely kill its orbital velocity, and then regain that velocity going in the opposite direction. If you know a little bit about rocket science you’d know that that’s pretty damn impressive. Okay, I’ll stop dancing around the main subject and get to it: thrusters and propellants used by the UNSC and Covenant are extremely friggin efficient. Modern day space stuff requires millions of gallons of fuel and multiple rocket stages to deliver even a small payload into orbit. But in Halo, dropship will carry tanks to orbit with less possible fuel storage space than a private jet. Spartans’ thruster packs can run for long periods of time to supplement sprinting, and can handle a seemingly infinite amount of short powerful bursts with no obvious fuel tanks on the armor. Jet packs can be used indefinitely with a short recharge period. So what sort of magic space juice is all this stuff running on? It has to be some sort of extremely low density fuel that can burn at an extremely high specific impulse. And I mean extremely high for any of this to make sense. It’s likely some sort of ionizes gas, but it can’t be anything actually currently known to man as we haven’t even theorized a chemicsl formula that could possibly be used like this. It could even be made from atmospheric gases and that’s why it’s seemingly infinite. Maybe the fuel thing hasn’t really been thought out and that’s why it’s like this, but I’m typing this under the assumption that it is. If you know more about chemistry than I do (I haven’t even taken high school chemistry) or rocketry in general you may have some better insight. Please do discuss it, because that’s what forums are for.

Also, I wrote this on my phone and spellcheck and swype were being -Yoinks!-, so if there’s anything funky within this please excuse it.

The ships use Fusion Drives.

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> The ships use Fusion Drives.

Perhaps Mjolnir armor’s thrusters also use the suit’s reactor to produce propellant as well. But I don’t know if the exhaust would be radioactive or not depending on what byproducts the fusion reactor creates.

they could also be repulsers like the Covie ships.

I always thought they were plasma-based, only rather than typical fuel it uses a sort of air compressor which draws in air from the atmosphere. That’s why we have to wait a short time between bursts, so the compressor can build up a charge again. Then it ionizes the gas and blasts it out the nozzles. Probably not very efficient, but it doesn’t have to be.

As for operation in a vacuum, perhaps it has a small reserve of more traditional fuel. This is all just guessing. It could also be some kind of sci-fi voodoo mini-fusion reactor, but something tells me that would still need fuel.

Thruster packs are fueled by triamino hydrazine, though I’m not sure if the same fuel is used for the thrusters built into GEN 2 armor.

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> Thruster packs are fueled by triamino hydrazine, though I’m not sure if the same fuel is used for the thrusters built into GEN 2 armor.

yeah, the jet pack and the old external thrusters used that but not sure about the in built Mjolnir thrusters.

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> they could also be repulsers like the Covie ships.

the UNSC have been unable to replicate special expansion engines.

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> > 2533274869573550;6:
> > Thruster packs are fueled by triamino hydrazine, though I’m not sure if the same fuel is used for the thrusters built into GEN 2 armor.
>
>
> yeah, the jet pack and the old external thrusters used that but not sure about the in built Mjolnir thrusters.

We can infer they are the same. Maybe only slightly different. If it ain’t broke don’t fix it

Keyes firing of the rockets didn’t kill all of their forward momentum, just most of it so that it came in on the covies more slowly.

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> > 2533274844984484;2:
> > The ships use Fusion Drives.
>
>
> Perhaps Mjolnir armor’s thrusters also use the suit’s reactor to produce propellant as well. But I don’t know if the exhaust would be radioactive or not depending on what byproducts the fusion reactor creates.

Maybe the exhaust passes trough some sort of filter?
I’m not great at chemistry so I’m not sure.

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> > 2533274844984484;7:
> > > 2533274869573550;6:
> > > Thruster packs are fueled by triamino hydrazine, though I’m not sure if the same fuel is used for the thrusters built into GEN 2 armor.
> >
> >
> > yeah, the jet pack and the old external thrusters used that but not sure about the in built Mjolnir thrusters.
>
>
> We can infer they are the same. Maybe only slightly different. If it ain’t broke don’t fix it

No. Attache thruster packs are terrible. They increase mass, have limited fuel and operational endurance, and are classified as environmental hazards due to the explosive contents of the jet packs fuel (minor malfunctions will kill you and possibly the guys next to you) and unreliability in less-then-perfect vacuum conditions (As seen in Ghosts of Onyx). They also require an entirely separate source of volatile materials (that your ship now has to carry in addition to all other supplies, plus regulations pertaining to the separation and storage of such materials) and components to be kept operational.

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> > 2533274924282060;3:
> > > 2533274844984484;2:
> > > The ships use Fusion Drives.
> >
> >
> > Perhaps Mjolnir armor’s thrusters also use the suit’s reactor to produce propellant as well. But I don’t know if the exhaust would be radioactive or not depending on what byproducts the fusion reactor creates.
>
>
> Maybe the exhaust passes trough some sort of filter?
> I’m not great at chemistry so I’m not sure.

Meh.

We’re (sorta) talking man-portable laser-based propulsion. Unfortunately, the problem comes down to how you can get it to work in space (which Blue Team did during the Raid on Argent Moon). On the ground, air itself can be the reactant mass necessary to produce thrust for movement and make for effective maneuvering when combined with intelligent structures/parabolic cones for precision movements. But again, that would only work in atmosphere. In space, storage devices are large and bulky, seeing only limited runtime and heavy fuel consumption.

And thats not even accounting for the fact that flames are constantly depicted as being blue in both atmosphere (an indication of a lower air to high fuel ratio/ stocihiometric mixtures) and vacuum (oxygen injected into reactor? Theres not much space for compressed oxygen storage, which would suggest very little time to begin with when the suit’s operator needs that air to breath) - which is funny because outside of injecting oxygen to the reactant mixture, would actually be inefficient due to the addition of storage packs for cooling and isolation. Of course, we could also consider that plasma exhaust in question, when referring to the fact that the observed MJOLNIR components were emitting blue exhaust, has a high transition energy which collates with ion/electron combinations and our limited view of the electromagnetic spectrum - and… oh look, this could actually fit with our interpretation of Deuterium-deuterium fusion (cause D+ is actually an isotope of hydrogen) and the fact that thrusters are only placed directly near the site of the micro-fusion reactor (four back, two front). Though from what I understand, oxygen still needs to play a role… whether it be to cool down the exhaust or whatnot. It does bring its own share of risks though, especially when you consider how close those exhaust ports are to your legs. restricting certain movements… plasma exhaust blowing across my torso? No thanks.

So we’ve got either typical plasma exhaust or some kind of electric powered propulsion system… which would cut down on total fuel consumption.

There also remains the possibility of microscopic soot having a role to play in all of this… but thats for an actual aerospace engineer or 343i employee to discuss.

Meh. Thats just my two-cents anyhow.

I’m sure Grim could explain it, but I doubt our primitive 21st-century human minds could comprehend it all.

<mark>This post has been edited by a moderator. Please do not bump.</mark>
*Original post. Click at your own discretion.

I’m more curious anout their air/spacecraft such as the pelican, falcon, and longsword

Well if you look up the Orion Drive which was a theoretical drive that was supposed to use nuclear blasts to achieve 1/10th the speed of light.

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> <mark>This post has been edited by a moderator. Please do not bump.</mark>*Original post. Click at your own discretion. I’m more curious anout their air/spacecraft such as the pelican, falcon, and longsword

A friendly warning to not revive old threads. This thread was back from 2015. Thanks.