Jetpack
A jet pack is a technology that is not yet practical but often appears in fiction. A jet pack is a device, normally worn on the back that allows a person to fly through the air.
Long a staple of science fiction used by The Rocketeer and James Bond, many in the real world have worked on devising a functional jet pack, with limited success. Currently the most advanced designs are more similar to helicopters than jets with an American company working towards a prototype of this model.
Similar to jetpacks are rocket pack, which rather than using jets of escaping gases employ rocket power for lift. Devices along these lines have been made using the engines from cruise missiles, but they are extremely dangerous and difficult to control and have never been flown. The heat from the rockets also tends to be too great.
In the 1960s Bell Labs built a device it called a rocket belt using hydrogen peroxide as fuel. This concept was revived in the 1990s and today these packs can provide powerful, but manageable thrust. The great disadvantage is that the limited amount of fuel that can be carried, currently only enough to fly for about 30 seconds.
Rocket packs are useful in orbit, however, and are used extensively by astronauts performing space walks. With only relatively small amounts of thrust needed safety and temperature are manageable.
While jet pack's look very appealing there is believed to be little practical use to them. The military, who have done must of the work in this field, find that helicopters can do most of what a jet pack could.
