Over the coming days, the top badminton players in the world will duke it out for control of the podium at the 2016 Olympics in Rio de Janeiro. And while the sport doesn’t get the same recognition, at least in North America, as others, what the athletes accomplish is truly extraordinary. The badminton shuttlecock is the fastest moving object outside of shooting sports at the Games.
It’s a surprising thing, given that a shuttlecock’s feathers are specifically engineered for air resistance. But that’s sort of the point — the faster the birdie slows, the harder the players can hit it and still keep the game in bounds.
The athletes swing their rackets with explosive force, and respond with superhuman reaction times. A recent study of the physics of the sport found that shuttlecocks flip over in just 20 milliseconds after contact with the racket. A hundred milliseconds later, and the birdie is perfectly aligned to its new direction of travel.
It’s these twin properties — drag and the propensity to always travel cork-forward, that make shuttlecock design so well suited for another application: space travel.
Getting a space shuttle out into space is one thing, landing it safely back on Earth or some other planetary body is another. One problem is slowing the shuttle down quickly enough to allow for a gentle landing, and another is preventing the air resistance to generate so much heat that the craft melts and falls apart like a terrible Perseid meteor shower.
Shuttlecock design, which traces its roots back to 2500 BC in Asia, kills both of these birdies with one stone. Not only do the feathers create a large amount of drag, but they spread the resistance out over a relatively large area, which reduces the buildup of heat. As a bonus, the this-way-up function of shuttlecocks as they fall mean that no extra energy is required to keep astronauts from tumbling violently through space during the descent.
The idea that shuttlecock physics could help with atmospheric reentry is not purely a matter of theoretical speculation. Virgin Galactic’s SpaceShipTwo, which the company hopes will one day take space tourists for low orbit rides, has a system of spinning “feathers” to aid with braking on reentry.
Unfortunately, a 2014 test of the system went horribly wrong when the feathered system was deployed too early, while the shuttle was still in powered ascent, which caused the craft to overheat and break apart. The copilot of the mission died in the crash, and the pilot parachuted back to Earth and suffered serious injuries.
The crash was a terrible setback, but Virgin Galactic wasted no time in building a replacement ship, and flight tests are due to begin within the next year.