Elon Musk Reveals 'Giant Party Balloon' Plan to Return SpaceX's Launched Rockets

Two SpaceX rocket boosters land in synchronized fashion after a Falcon Heavy launch in February. SpaceX/public domain

SpaceX might use a "giant party balloon" to retrieve rocket parts after a launch, according to CEO Elon Musk.

The space company owner tweeted his plan for the upper stage of SpaceX's rockets, which could be reused if they are returned safely to Earth after liftoff.

SpaceX already has a system in place for returning the first stages of its rockets, which it has demonstrated with the boosters landing upright.

This is gonna sound crazy, but …

— Elon Musk (@elonmusk) April 15, 2018

"This is gonna sound crazy, but…SpaceX will try to bring rocket upper stage back from orbital velocity using a giant party balloon," he wrote over the weekend. Musk added, "and then land on a bouncy house."

Calling the equipment to allow the rocket upper stage's re-entry a giant party balloon might paint a picture of a huge plastic cartoon character filled with helium, but it's a more sophisticated system. The balloon slows down the rocket as it re-enters the atmosphere. In the replies of his Twitter thread, Musk confirmed that he was talking about a special kind of decelerator that significantly brings down the speed of the falling object before it reaches the ground.

SpaceX CEO Elon Musk is hoping to retrieve rocket upper stages after future launches. SpaceX/public domain

Vehicles re-entering the planet's atmosphere from low-Earth orbit are moving several thousand miles per hour. For comparison, the speed of sound is closer to 760 miles per hour. In order to retrieve an object that is returning to Earth without it being blasted to bits, it would have to be moving much slower than that.

"We're going to try a few approaches," Musk said. "Can [definitely] be done, just about minimizing mass."

Musk is known for his stunts and for his humorous commentary on social media. Earlier this year, SpaceX launched an enormous rocket called Falcon Heavy for the first time and, because it was a maiden voyage, used test cargo: the CEO's convertible. The red Tesla Roadster—Musk is also the CEO of electric car company Tesla—had a dummy dressed as an astronaut in the driver's seat and a David Bowie song played as it soared into space toward its new home, an orbital path in the asteroid belt.