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 don’t just have one level of redundancy, one emergency 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 skydiving fatalities 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, says Chris Stephen, CEO of Canadian Aerosports, a Vancouver-based parachute maker that had a shop in Montreal until the late 1980s. “They’re round parachutes, the technology hasn’t changed much since Apollo, there are just new materials.”
Some of these new materials have helped improve recreational parachutes, Montanez said. “There is also a lot of work done by space parachute manufacturers on modeling, to be sure of safety,” he says. These modeling software are eventually available to all manufacturers, it helps to design new parachutes. »
For Starliner and Boeing, the problems were with the cables connecting the three parachutes to the capsule, Mr. Stephen said. For SpaceX, a new, lighter material proved vulnerable to the Sun’s ultraviolet rays and opening shock.
“SpaceX has halved the weight of its parachutes compared to those of Boeing and Starliner,” says 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 Boeing Starliner. »
In 2019, after an unmanned test of the Dragon capsule failed because none of its three parachutes opened, Elon Musk said: “Parachutes look easy, but they’re not really not easy. »
The total weight of Dragon’s parachutes is less than 250 kg, according to Stephen.