The 
Jetpack is a Mekanism chest piece that’ll let you fly by burning Hydrogen, and it’s one of the first pieces of gear that you’re able to make once you’ve got Steel and a 
Basic Control Circuit. It holds 24,000 mB of Hydrogen, which is enough for 20 minutes of thrust, and it has to be filled inside a machine as it can’t be topped up by right-clicking a tank.
There are four modes to switch between, which are Regular, Hover, Vector and Disabled, and they’re changed with the 
Chest Mode Switch key, which is G by default. Later on you can turn it into an 
Armored Jetpack, which flies in the same way but gives you the armor of a 
Diamond Chestplate as well.
How to Get It
You’ll craft the Jetpack from 2 
Steel Ingots, 3 
Tin Ingots, a Basic Control Circuit and a 
Basic Chemical Tank. The tank is the part that takes the longest, as it needs 4 
Osmium Ingots and some 
Redstone Dust, but none of it needs more than a 
Metallurgic Infuser to make.
The Armored Jetpack is an upgrade that’s crafted around a Jetpack you’ve already made, with 2 
Diamond Dust, 2 
Bronze Ingots and a 
Block of Steel. Any Hydrogen that’s still inside is kept when you craft it, so there’s no need to empty the Jetpack first.
How to Use It
Filling It with Hydrogen
A new Jetpack comes out empty, and it won’t do anything until there’s Hydrogen in it. You’ll get Hydrogen from an 
Electrolytic Separator, which splits Water into Hydrogen and Oxygen, and the easiest way to fill up is to put the Jetpack straight into the item slot that’s under the Hydrogen tank on the left of its screen.
The other way is to pipe the Hydrogen into a Chemical Tank first and then place the Jetpack in the tank’s top item slot, the one marked with a plus, which will drain the tank into it. Either way it fills at 16 mB every tick, so going from empty to full takes 75 seconds as long as there’s enough Hydrogen waiting.
The Jetpack holds a chemical and not energy, so standing on a 
Chargepad or putting it in an Energy Cube will do nothing for it. Right-clicking a Chemical Tank with it in your hand won’t fill it either, as it has to go into a slot.
A Separator with no upgrades only makes 2 mB of Hydrogen a tick, which is much slower than the Jetpack is able to take it in. It’s worth letting a Basic Chemical Tank fill up while you’re doing something else, as it holds 64,000 mB and that’s enough to refill an empty Jetpack twice over.
Jetpack Modes
The mode is changed by pressing the Chest Mode Switch key while you’re wearing the Jetpack, and a message will tell you which one you’ve moved to. It starts in Regular, and holding sneak while you press the key will cycle backwards through the list instead.
| Mode | How It Flies | When It Burns Hydrogen |
|---|---|---|
| Regular | Hold jump to climb, let go to fall | Only while jump is held |
| Hover | Holds your height; jump rises and sneak descends | The whole time you’re off the ground |
| Vector | Pushes in the direction your body is tilted; sneak makes it act like Regular | Only while jump is held |
| Disabled | No thrust at all | Never |
Hover is the comfortable one to build with, as you’ll stay level without touching anything, but it’s also the mode that’ll empty the tank without you noticing. It keeps burning for as long as your feet are off the ground, even when you’re holding still, so switch back to Regular or Disabled once you’ve landed somewhere high up.
Flight Time and Armor
A Jetpack burns 1 mB of Hydrogen for every tick that it’s thrusting, so a full tank of 24,000 mB will last for 20 minutes of flight. The amount that’s left is shown on the Mekanism HUD along with the mode, and once it reaches zero the thrust just stops, which means you’ll fall from wherever you were.
Firing it on the way down will cancel fall damage, as your fall distance is reset while there’s thrust, so it’s worth keeping a little Hydrogen back for the landing. It won’t work while you’re riding something, like a Horse or a Boat, and it takes up the chest slot, so it can’t be worn together with a 
Scuba Tank.
The plain Jetpack gives no armor at all, whereas the Armored Jetpack has 8 armor and 2 toughness, the same as a Diamond Chestplate. Much later, a 
Jetpack Unit can be installed in the MekaSuit to do the same job, and for falls that happen when you’re out of Hydrogen there’s the 
Free Runners, which are the boots to make next.
FAQ
The Jetpack is filled with Hydrogen by placing it in a machine’s item slot, either the one under the Hydrogen tank of an Electrolytic Separator or the top slot of a Chemical Tank that’s holding Hydrogen. It takes in 16 mB a tick, so a full 24,000 mB needs 75 seconds, and right-clicking a tank with it won’t work.
You’ll need to be wearing it and then press the Chest Mode Switch key, which is G unless you’ve changed it in the controls. Each press moves on through Regular, Hover, Vector and Disabled, and holding sneak at the same time goes back the other way.
A full tank holds 24,000 mB of Hydrogen and it burns 1 mB for each tick of thrust, which works out at 20 minutes. In Regular mode that’s only counted while you’re holding jump, whereas Hover uses it up for the whole time you’re in the air, so it’ll run out sooner if you leave it hovering.
They fly in exactly the same way and hold the same 24,000 mB of Hydrogen, but the Armored Jetpack adds 8 armor and 2 toughness, which matches a Diamond Chestplate. It’s crafted from a Jetpack with 2 Diamond Dust, 2 Bronze Ingots and a Block of Steel, and the Hydrogen inside carries over as well.
