NASA along with the European Space Agency successfully used an experimental "interplanetary Internet" to control a small LEGO robot on Earth. The commands came from space and "demonstrate technology that one day may enable Internet-like communications with space vehicles and support habitats or infrastructure on another planet," NASA said in a press release.
So what's the big deal, you ask? Well, this is a first step in building an infrastructure that would allow us to communicate through the astronomical distances in space.
And why couldn't they just use the regular old Internet in space? As NASA explains in this video from 2008, our Earthly Internet isn't designed to travel such long distances and doesn't take well to interruptions.
NASA's Disruption Tolerant Networking on the other hand is designed specifically to deal with the unpredictable.
Here's how NASA explains it:
"The DTN architecture is a new communications technology that enables standardized communications similar to the Internet to function over long distances and through time delays associated with on-orbit or deep space spacecraft or robotic systems. The core of the DTN suite is the Bundle Protocol (BP), which is roughly equivalent to the Internet Protocol (IP) that serves as the core of the Internet on Earth. While IP assumes a continuous end-to-end data path exists between the user and a remote space system, DTN accounts for disconnections and errors. In DTN, data move through the network "hop-by-hop." While waiting for the next link to become connected, bundles are temporarily stored and then forwarded to the next node when the link becomes available."
So, for example, a probe orbiting Jupiter could send a data packet to a rover sitting on Mars, which could hold that "packet" until it got a clear view of a probe orbiting the planet, which could then relay it to the International Space Station.