The ballute (a portmanteau of balloon and parachute) is a parachute-like braking device optimized for use at high altitudes and supersonic velocities. The original ballute configuration was invented in 1948 by the Goodyear company. The innovation soon caught the attention of other organisations, including NASA; the agency incorporated ballutes into the escape system of the Gemini spacecraft. It has subsequently seen extensive use within the aerospace sector as a means of retarding the descent of various payloads, such as sections of rockets and atmospheric probes. Various proposals involving ballutes, such as for deorbiting/recovering low-mass satellites and interplanetary research programmes, have been issued in recent decades. Design The ballute is an inflatable device used to generate drag. In terms of its basic configuration, it is a cone-shaped balloon, featuring a toroidal burble fence (an inflated structure intended to ensure flow separation) that is fitted around its widest point. The burble fence acts to stabilize the ballute as it decelerates through different flow regimes, typically descending from faster (even supersonic) flows into subsonic speeds. The design of the ballute, particularly its drop-like shaping, make it more suitable for decelerating at extreme speeds than a conventional parachute. Ballutes can be categorised into three primary configuration, these being cocoon ballutes that enclose their payloads, attached ballutes that attach directly to the base of their payloads, and towed ballutes that trail after their payloads. The isotensoid ballute has been recognised as the standard configuration, although other arrangements have been tested. It has been proposed that ballutes could be arranged in both stacked toroidal and tension cone form factors. Some ballute configurations are specialised to certain purposes or industries, such as the aerospace sector. By attaching a ballute to an air-dropped object, such as a bomb or an aerospace payload, it should (provided it is of sufficient size and has correctly deployed) limit its rate of descent, potentially minimising damage to the payload on contact with the ground. They can generate a relatively high amount of drag for their mass, making them attractive in weight-constrained scenarios typical to aerospace applications. Inflation of a ballute is typically achieved either by a gas generator or by external air being forced into the structure by an arrangement of ram air inlets. The design of the inflation mechanism is particularly critical to its successful application; if the inlets are too small or too few, the ballute shall not maintain its