China’s People’s Liberation ArmyNavy just reached a significant milestone in its efforts to develop a globally-capable “blue water” navy, as the nation’s second aircraft carrier entered service on Tuesday.

China’s new carrier, dubbed the Shandong, is not only China’s first home-built vessel of its type, it also earns the nation a place in the elite fraternity of countries boasting more than a single large flat-top. While there is some debate as to what qualifies as an aircraft carrier (the United States could arguably have as many as 24 depending on how loose your definition is) there are still only around six other nations on the planet that maintain more than one carrier in their fleets.

This second carrier, however, shares one significant weakness with its Soviet-built peer, China’s Liaoning: Neither vessel is nuclear powered. That means that, just like the rest of China’s Navy, these carriers are dramatically limited in their operational range. America’s Nimitz and Ford-class super carriers, for instance, run on nuclear power and can go for years between refueling. Of course, many of the vessels that travel in America’s carrier strike groups do still rely on diesel fuel for propulsion, but America’s vast network of military and otherwise friendly ports the globe over make blue water operations a fact of life for America’s Navy.