This rocket backpack has sensors that know exactly how far you are from the ground and what your upward and downward velocity is.
When it senses you've jumped, the jets kick in and blast you to a preset height. At your apogee, zenith, nadir, pinnacle, apex, crest, summit it starts to correct for your downward plunge so you don't die, hitting the ground just lightly enough to return you to a readied crouch at which point you jump again.-- doctorremulac3, Jun 19 2017 It's a good idea, but perhaps a little obvious given it's level of parbakedness in popular fiction - from Heinlein's starship troopers through to several current generation computer games.
I think it would have merit if a) you proposed how to get it to work, ie contrast against current jet pack technology and show how this could be done, or b) come up with a novel aspect to it, like powering it with a big helium baloon (and tank, and compressor) that inflates to lift you and then deflates/compresses the helium to reduce lift. Or electrolysis water (in the air?) to produce hydrogen for lift and then burns the hydrogen for thrust or something.
Because jetpacks are rather WKNTE, but workable practical ones are WIBNI without a new fuel/technology.-- Custardguts, Jun 19 2017 Hmm. Valid points.
Ok, maybe a jetpack balloon hybrid. Just enough balloon to cut the load to the rocket pack in half but not so big that it imparts too much drag to the whole arrangement.-- doctorremulac3, Jun 20 2017 I think that's going to be a very large balloon.-- RayfordSteele, Jun 20 2017 random, halfbakery