NASA's Low-Earth Orbit Flight Test of an Inflatable Decelerator, or LOFTID, is demonstrating technology for atmospheric entry.

LOFTID acts as a giant brake by deploying a large inflatable aeroshell (a deployable structure protected by a flexible heatshield) before entering the atmosphere. The large aeroshell creates more drag and begins slowing down in the upper reaches of the atmosphere, allowing the spacecraft to decelerate sooner while experiencing less intense heating.

Elon tweeted in April, SpaceX will try to bring rocket upper stage back from orbital velocity using a giant party balloon. This was referring to an inflatable hypersonic aeroshell.