BE-4 engines during ground testing. Blue Origin Key to any rocketship is the complex, powerful engines that blast it into space, and right now a private spaceflight company called Blue Origin is working on a monster one that could eventually shuttle humans to space.

Blue Origin is the private spaceflight company owned by ambitious billionaire and Amazon-founder Jeff Bezos.

In late November, the company successfully flew its New Shepard spaceflight vehicle, which is powered by BE-3 engines.

Upon ignition, each BE-3 engine generates 110,000 pounds of thrust — the propulsive force a rocket uses to get to space.

But that's nothing compared to the company's BE-4 engines (illustrated below), currently under development and testing at Blue Origin's base in west Texas.

Blue Origin

When ready for flight, each BE-4 engine will blast off the planet with 550,000 pounds of thrust — five times more power than the BE-3 engines.

For comparison, the engines that powered the rockets that launched NASA's Space Shuttles into space produced 418,000 pounds of thrust.

"The BE-4 engine will begin full-engine development testing next year, with qualification testing completed by the end of 2017. The engine is then ready for flight," Rob Meyerson, President of Blue Origin, told Business Insider. "We began development of the BE-4 in 2011 and recently completed the Critical Design Review, an important milestone prior to full-engine testing."

Sending Americans to space on US soil

Already, Blue Origin's BE-4 monster engines have attracted the attention of the private spaceflight services company United Launch Alliance, who has contracted Blue Origin to fly the engines on ULA's most powerful rocket yet, called Vulcan — which is currently under development.

An United Launch Alliance's Atlas V rocket launch. Uploaded by Craigboy to Wikipedia "Our baseline plan is for the Vulcan booster to fly booster with two, BE-4 engines each, but ULA is also carrying Aerojet Rocketdyne’s AR-1 engine as a backup," George Sowers, ULA’s Vice President of Advanced Programs, told Business Insider.

With two BE-4 engines, the Vulcan will generate 1.1 million pounds of thrust, capable of transporting up to 50,000 pounds of payload into high orbits around the Earth — an important capability for traveling to distant destinations like the moon and Mars.

Since it was founded in 2006, ULA has launched more than 100 successful spaceflights in a row, boasting the highest success rate of any US private launch business.

ULA hopes to fly Vulcan for the first time in 2019, but in the mean time, it'll continue fulfilling contracts with its Atlas V, Delta IV, and Delta II rockets.

Currently, ULA does not launch humans into space but rather transports satellites into space for the US government and private spaceflight companies like Orbital ATK. But that could change in the future.

"Vulcan will be used for all missions currently served by Atlas V and Delta IV, including national security, NASA science, commercial and human mission," Sowers told Business Insider. "ULA will be happy to provide Vulcan to NASA for any of its launch needs."

Blue Origin says that shortly after testing is complete on its BE-4 engines in 2017, it'll send the engines to ULA so that the company can begin integrating the engines into their Vulcan rocket to prep for the first flight in 2019.