Satellite images show China building a big aircraft carrier believed to be its first modern flattop

China has one carrier — the Type 001 Liaoning — in service with the People's Liberation Army Navy. Formerly a rusting, unfinished Soviet heavy aircraft-carrying cruiser, the Liaoning is now the flagship of the Chinese navy.

China is close to fielding its second aircraft carrier — the Type 001A, the country's first domestically produced carrier.

The ship, based on the Liaoning, recently completed its fifth sea trial, and the Pentagon expects this vessel will "likely join the fleet by the end of 2019."

China's first and second carriers are conventionally powered ships with ski jump-assisted short take-off-but-arrested-recovery (STOBAR) launch systems, which are less effective than steam- or electromagnetically powered catapult-assisted-takeoff-but-arrested-recovery (CATOBAR) launch systems.

The third carrier is expected to be significantly larger than the first two carriers (but still smaller than US carriers) and have a CATOBAR launch system. "This design will enable it to support additional fighter aircraft, fixed-wing early-warning aircraft, and more rapid flight operations," the Department of Defense concluded.

"If the third carrier does have some catapult-assisted launch system, that will be a huge step forward for China," Matthew Funaiole, a fellow with the China Power Project at CSIS, previously told Business Insider.

Read more: China's aircraft carriers have a boatload of glaring weaknesses — but the next carrier could be a 'huge step forward'

"They would very quickly have moved closer to what current technology is. That's something that very few countries can do. That would put China in a very elite status," Funaiole said.

China's third carrier is expected to join the fleet in about 2022.