Elon Musk Wants to Test Out SpaceX Rockets That Land With 'Giant Party Balloons'
Musk recently mused on Twitter that in his goal of recovering and reusing as much of a rocket as possible - in which SpaceX has a great but not perfect record - SpaceX will try attaching a "giant party balloon" to the upper stage of a rocket, which could more safely carry it back from orbit to Earth's surface.
SpaceX will try to bring rocket upper stage back from orbital velocity using a giant party balloon— Elon Musk (@elonmusk) April 15, 2018
Currently, most Falcon 9 rockets only preserve the first stages of the rockets, and sometimes the boosters of bigger rockets like the Falcon Heavy, but SpaceX doesn't usually attempt to save the upper stages from either burning up in the atmosphere or a watery death if they crash into the ocean below.
He elaborated a little more afterward on how sturdy a specialized balloon could potentially be while traveling in Earth's atmosphere:
Yeah, but great for creating a giant object that retains its shape across all Mach regimes & drops ballistic coefficient by 2 orders of magnitude— Elon Musk (@elonmusk) April 15, 2018
Musk further went on to say the rocket would then land on a "giant bouncy house". Now, it's easy to say "this is just a joke", and if we were talking about anyone besides Elon Musk, that'd be a good reason not to read much into this.
But Elon Musk is the guy who joked that he would dig underground tunnels in Los Angeles to beat traffic, and then started The Boring Company and is now working on an improved alternative to subway systems. He then joked that he'd sell flamethrowers with the logo on them, and then he did, and then they sold out. He earned a lot of flamethrower money from that joke, and The Boring Company is now digging tunnels under multiple cities.
Musk recently described a landing pad for a rocket nose cone as a "giant catcher's mitt," and he could very well be using similar euphemisms to refer to an inflatable landing pad as a "giant bouncy house" and a legitimate hot air propulsion system as a "party balloon". Both would be new ideas since few other companies launch rockets like SpaceX.
Other tech companies are beginning to experiment more with balloons, with Alphabet's Project Loon - which sends balloons to different parts of the world to act as mobile cell towers - being one of the most prominent examples. Project Loon has held some very successful tests so far, and they've since split from Alphabet into their own company.
So if at some point in the future, SpaceX launches a rocket with balloons attached, or at least ready to deploy, we'll know he was serious.