Three startups are getting ready to launch one of the most ambitious and important cryptocurrency experiments since the creation of bitcoin itself. Called Lightning, the project aims to build a fast, scalable, and cryptographically secure payment network layered on top of the existing bitcoin network.

Essentially, Lightning aims to solve the big problem that has loomed over bitcoin in recent years: Satoshi Nakamoto’s design for bitcoin is comically unscalable. It requires every full node in bitcoin’s peer-to-peer network to receive and store a copy of every transaction ever made on the network.

Initially, that design was vital to achieving Nakamoto’s vision of a fully decentralized payment network. But as Purdue computer scientist Pedro Moreno-Sanchez told Ars, it creates a big challenge as the network becomes more popular. “We have reached a point where it’s not suitable any more to keep growing,” he said.