increases throttle. Jetpack Aviation was started by Australian businessman David Mayman with the technical knowhow coming from Nelson Tyler, prolific inventor of helicopter-mounted camera stabilizers and one of the engineers that worked on the Bell Rocketbelt that was used in the 1984 Olympics. The company now makes two Jetpack models, the JB-10 and the JB-11. They are similar to the JB-9, with upgraded electronics. They both use kerosene/diesel turbojet engines. The JB-10 is designed with two large 200 lb. thrust engines and is described as having an 8 minute flight time, while the slightly-longer duration JB-11 has a 10 minute flight time and uses eight smaller 90 lb. thrust engines. Jetpack Aviation Flyboard Air Flyboard Air, invented by Franky Zapata, allows flight up to and can reach . It also has 10 minutes autonomy. Zapata participated with his invention during the 2019 Bastille Day military parade. Three weeks later, he crossed the English Channel with his device in 22 minutes, including a shipboard refueling midway. Daedalus Flight Pack This particular innovation saw two jets attached to the back of an exoskeleton, worn by the operator. At the same time, two additional jets were added to the arms, and could be moved with the arms to control movement. It was devised by Richard Browning of Gravity Industries. In September 2020 it was reported that the Great North Air Ambulance (GNAA) service was considering using this jet suit to enable paramedics to reach casualties in the mountainous Lake District, and by March 2022 the operational director of the GNAA, Andy Mawson, had been trained to fly and the service hoped to start using jet suits in summer 2022. Government Space Rocket packs can be useful for spacewalks. While near Earth a jet pack has to produce a g-force of at least 1g (a smaller g-force, providing only some deviation from free fall is of little use here), for excursions outside a free falling spaceship, a small g-force providing a small deviation from free fall is quite useful. Hence much less delta-v is consumed per unit time, and not during the whole EVA. With only small amounts of thrust needed, safety and temperature are much more manageable than in the atmosphere in Earth's gravity field. Nevertheless, it is currently worn to be used only in case of emergency: the Simplified Aid For EVA Rescue (SAFER). Hydrojet packs The 21st century has seen a