Before man could conquer space, scientists needed to recreate weightlessness without going into orbit. Animals could survive in zero-gravity conditions – that much had been proven. But could the human body adapt? Would our organs still function? And how could we tell? In the 1950s, scientists hit on the solution: parabolic flights.
From the 1950s, pilots honed a special aerial maneuver, the parabolic maneuver, which reproduced short gravity-free periods of up to 30 seconds, depending on the zero-gravity aircraft in question.
The first aircraft to make these zero-gravity parabolic flights were two-seater fighters and training aircraft (T-33, F-89, F-94C). The first tests were conducted by the pilots and passengers themselves, strapped into their seats, like human guinea pigs. Scientists collected a lot of data about human physiology in microgravity conditions, such as sense of direction, illusions, breathing, the cardiovascular system, and motor and cognitive performance. These were the sorts of aircraft used to train the first astronauts: John Glenn and the astronauts from the Mercury space program in the United States, and Yuri Gagarin and the Vostok cosmonauts. However, the size of the cockpits in these aircraft left little room for experiments.
From the 1960s, bigger aircraft – Convair C-131 and then KC-135 in the United States, Tu-104 AK and then Ilyouchine 76-MDK in the USSR – began to be used for gravity-free flights. The cabins were wide enough to accommodate dozens of passengers and bulkier scientific equipment.
Fairly basic until then, parabolic flights received a major boost from these developments. Since scientists could take flights themselves, zero-gravity research was extended to other disciplines – fundamental physics, fluid physics, human and animal biology and physiology, and technology. These aircraft were flying science labs. The number of flights soared, equal to several days of accumulated weightlessness.
France is Europe’s parabolic flight pioneer: the French National Center for Space Studies (CNES) and its flight test center (CEV) operated parabolic flights from 1989 using a Caravelle VI-R, spurred on by astronauts Jean-François Clervoy and Jean-Pierre Haigneré, who got the ball rolling.
CNES tasked its subsidiary, Novespace, with marketing the service, leading to the first scientific parabolic flight campaigns for Europeans, who were now able to operate independently in this field. By the time Caravelle had been taken out of service in 1995, it had completed more than 40 scientific flight campaigns, and more than 4,000 parabolas, equivalent to 24 gravity-free hours. It was replaced by the Airbus A300 Zero G, which Novespace operated for 17 years. When it made its last flight in 2014, it had completed 102 scientific flight campaigns and six gravity-free discovery flights, for a total of more than 13,000 parabolas and 72 accumulated hours of weightlessness.
In April 2015, Novespace began operating its third aircraft, the Airbus A310 Zero G.
In 2017, only three airliners in the world operated gravity-free flights; the Airbus A310 Zero G in France is the largest. Smaller aircraft, mostly business jets, are also operated for parabolic flights in other countries, such as Japan, Canada and the Netherlands.
Parabolic flights are now accessible to individuals and companies outside the space industry, keen to discover the wonders of weightlessness. For example, Novespace has organized Air Zero G gravity-free discovery flights in Bordeaux-Mérignac (France) since 2013. These flights are marketed by France’s leading air broker, Avico.
Private companies can also book parabolic flights for more specific reasons, such as business events, or to shoot gravity-free scenes for the movies.