Why do the parachutes of space capsules bringing humans back to Earth never fail and always open? Luck or foolproof technology?
Marc Julien
Because they are tested more thoroughly than normal parachutes, and because there are sometimes two levels of redundancy.
“Space capsule parachutes are tested much more than other parachutes because they are subjected to extreme conditions,” says Roberto Montanez, CEO of Butler Parachute Systems in Virginia and president of the Parachute Industry Association. “And we not only have one level of redundancy, a reserve parachute, but sometimes two. »
Typically, parachutes are designed to fail 1 in 1,000 times, Montanez says. For this reason, recreational skydivers have a reserve parachute, often triggered by an altimeter. For 30 years, the number of recreational parachute deaths in the United States has varied between 10 and 30 per year, with 5,000 emergency parachute openings, out of more than 3 million jumps per year.
Space parachutes are simpler than recreational parachutes, which are often rectangular, according to Chris Stephen, CEO of Canadian Aerosports, a Vancouver parachute manufacturer that had its workshop in Montreal until the late 1980s. round parachutes, the technology hasn’t changed much since Apollo, there are simply new materials. »
Some of these new materials have improved recreational parachutes, according to Montanez. “There is also a lot of work done by space parachute manufacturers on modeling, to be sure of safety,” he said. These modeling software are eventually available to all manufacturers, it helps to design new parachutes. »
The capsule Starliner of Boeing, which has just successfully completed its first human flight to the American Space Station, the lunar capsule Orionas well as the capsule Dragon of SpaceX have however experienced problems in the development of their parachutes.
For Starliner and Boeing, the problems were related to the cables connecting the three parachutes to the capsule, according to Mr. Stephen. For SpaceX, a new, lighter material proved vulnerable to the Sun’s ultraviolet rays and the opening shock.
“SpaceX has halved the weight of its parachutes compared to those of Boeing and Starliner, said Mr. Stephen. This is a very significant improvement. This is, among other things, what allows them to have a cost per astronaut, to go to the Space Station, of 55 million US compared to 90 million US for the Starliner from Boeing. »
In 2019, after an unmanned test of the capsule Dragon failed because none of his three parachutes opened, Elon Musk said: “Parachutes look easy, but they’re really not easy. »
The total weight of the parachutes Dragon is less than 250 kg, according to Mr. Stephen.
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- 42
- Number of deaths per year in recreational skydiving in the 1970s in the United States
Source: United States Parachute Association
- 16
- Number of deaths per year in recreational skydiving since 2000, in the United States
Source: United States Parachute Association