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Christmas Gift Guide

Rolling out a new world record

Mark your calendars for a 2019 rocket launch

Testing the engines for the first time

Stratolaunch has passed all its tests with flying colors so far

This is one gigantic plane

The Stratolaunch concept

A bicipital airplane

No one's home on the port side, though

How the Stratolaunch launches rockets

It can launch up to 3 rockets per flight

A plane this heavy needs lots of wheels

A Boeing 747-400 to be harvested for parts

This is what the Stratolaunch's cockpit looks like

During the building process

The beginnings of the Stratolaunch

Meet Paul Allen, the man behind the plane

Fulfilling his life's dream

The first step toward flight

Monitoring the build progress

The rear view

There are 6 powerful engines...

This plane needs a LOT of runway

A quick look under the plane

Launching rockets; launching innovations

World's largest aircraft gets ready to fly

A Stratolaunch class photo

Welcome to America's first Space Port

A visit to the Mojave Space Port

Paul Allen's first spaceship

SpaceShipOne: A prize-winning craft

This is the Stratolaunch. With a wingspan of 385 feet, this special plane is now the largest in the world. Don't expect to see it at your local airport though; this craft has a more important purpose than transporting people.

Why is everyone talking about this plane? Take a closer look at it, and you'll soon see for yourself...

Caption by / Photo by Stratolaunch Systems

On May 31, 2017, the Stratolaunch was towed out of its hangar to start ground testing. Its first takeoff is planned for later this year following further tests.

If all goes well, the Stratolaunch will perform its first rocket launch sometime in 2019.

Caption by / Photo by Stratolaunch Systems

On Sept. 19, 2017, the Stratolaunch successfully completed a series of important engine tests, with all six Pratt & Whitney turbofan engines performing as expected.

Caption by / Photo by Dylan Schwartz/Stratolaunch

The Stratolaunch has also completed fuel testing in recent months, along with testing of its electrical, pneumatic and fire-detection systems.

Crews will continue to test the engines at even higher power levels in the months to follow as the Stratolaunch works toward its first taxi test.

Caption by / Photo by Dylan Schwartz/Stratolaunch

By the numbers, the Stratolaunch -- code name "Roc" -- is the largest plane ever built. Its wings measure 385 feet across, longer than a professional football field. Its twin fuselages are 238 feet long, while its tail height is 50 feet.

As such, it had to be constructed here at the Mojave Air and Space Port, inside a specially constructed 88,000-square-foot hangar.

Caption by / Photo by Stratolaunch Systems

The Stratolaunch has yet to make its maiden flight, but this concept photo shows what that might look like.

If you look between the two fuselages, you'll see three rockets designed to launch into space.

Caption by / Photo by Stratolaunch Systems

No, you're not seeing double -- the Stratolaunch really is a two-headed airplane. But only the cockpit on the starboard (right when facing forward) fuselage is manned.

Caption by / Photo by Stratolaunch Systems

The port side cockpit, meanwhile, is designed to stay empty and unpressurized.

Caption by / Photo by Stratolaunch Systems

This graphic shows the planned operation of the Stratolaunch. The plane first carries a rocket to an altitude of roughly 35,000 feet. The rocket then separates from the plane and engages its own engines to continue its climb.

Caption by / Photo by Stratolaunch Systems

For its first launch in 2019, the Stratolaunch will carry a single Pegasus XL rocket, built by Orbital ATK. The craft is designed, however, to carry as many as three of these between its twin fuselages.

Caption by / Photo by Stratolaunch Systems

With a max takeoff weight of 1.3 million pounds (650 tons), the Stratolaunch needs a lot of support from its 28 wheels.

There are 12 main landing-gear wheels and two nose-gear wheels on each side.

Caption by / Photo by Stratolaunch Systems

Many of the systems of the Stratolaunch were borrowed from Boeing 747-400 planes in the most literal sense. Engineers cannibalized the engines, avionics, flight decks and landing gear of two such planes during the building process, including the one shown here.

Caption by / Photo by Stratolaunch Systems

This is the inside of a Boeing 747-400, showing you what the cockpit of the Stratolaunch looks like. The record-breaking plane is designed to operate under a three-person crew: the pilot, co-pilot and flight engineer.

Caption by / Photo by Brooks Kraft/Corbis/Getty Images

Once the Stratolaunch has proved itself in testing, the craft is expected to participate in six to 10 missions per year.

Caption by / Photo by Stratolaunch Systems

Here's a wide shot of the massive Stratolaunch Systems hangar from 2015. In this photo, you can take a barest-of-bones look at the early days of the plane's construction.

Caption by / Photo by Paul G. Allen

This is Microsoft co-founder Paul Allen. He and Scaled Composites founder Burt Rutan created Stratolaunch Systems on Dec. 13, 2011, to develop a new air-launch-to-orbit system that could revolutionize space transportation.

Caption by / Photo by Paul G. Allen (@PaulGAllen)

When you're the sole financier of a plane, you're allowed to climb this high for a photo op.

"It is a big initial fixed investment to get this going," Allen said when announcing the project in 2011. "But you have a certain number of dreams in your life that you want to fulfill, and this is a dream that I'm very excited about seeing come to fruition."

Caption by / Photo by Paul G. Allen

"Over the past few weeks, we have removed the fabrication infrastructure, including the three-story scaffolding surrounding the aircraft, and rested the aircraft's full weight on its 28 wheels for the first time," said Stratolaunch Systems CEO Jean Floyd. "This was a crucial step in preparing the aircraft for ground testing, engine runs, taxi tests and, ultimately, first flight."

Caption by / Photo by Stratolaunch Systems

Here, Allen and his team check the progress on the Stratolaunch prior to officially unveiling it.

Caption by / Photo by Paul G. Allen

Here's a look at the rear of the Stratolaunch.

Caption by / Photo by Stratolaunch Systems

The Stratolaunch is powered by six 250 kN (56,000 lbf) Pratt & Whitney PW4056 engines harvested from the Boeing 747-400s.

Caption by / Photo by Stratolaunch Systems

Because of its immense size and weight, the Stratolaunch needs 12,000 feet of runway -- nearly 2 miles' worth -- to take off.

Caption by / Photo by Stratolaunch Systems

Here's a look at the underside of the Stratolaunch while in its Mojave Desert hangar.

Caption by / Photo by Stratolaunch Systems

Allen's motivations for building and financing the Stratolaunch were made clear in a 2016 statement.

"When such access to space is routine, innovation will accelerate in ways beyond what we can currently imagine," he wrote. "That's the thing about new platforms: when they become easily available, convenient and affordable, they attract and enable other visionaries and entrepreneurs to realize more new concepts."

Caption by / Photo by Stratolaunch Systems

The massive Stratolaunch leaves its hangar for the first time to start new rounds of testing.

Caption by

Allen and the Stratolaunch Systems team pose for a photo near one of the plane's two tails.

Caption by / Photo by Paul G. Allen

The Stratolaunch is being built and tested at the Mojave Air and Space Port, located in California's Mojave desert. It's the first facility to be licensed by the Federal Aviation Administration as a "spaceport" to support reusable spacecraft.

Caption by / Photo by Mojave Air and Space Port

Of course, the Stratolaunch isn't the only strange private spacecraft at the Mojave Space Port. Check out the Rotary Rocket, an odd private launch vehicle from the late 1990s that was powered by a helicopter-like rotary blade. It made three successful hover flights in 1999.

The Rotary Rocket Company ultimately ran out of funds and was abandoned in 2001.

Caption by / Photo by Mojave Air and Space Port

This is neither Rutan's (left) nor Allen's first attempt at creating a commercially viable aircraft. The duo teamed up over a decade ago to build SpaceShipOne at the Mojave Space Port, the first privately built and piloted reusable vehicle to reach space.

That ship is now on display at the National Air and Space Museum in Washington, D.C.

Caption by / Photo by Win McNamee/Getty Images

On October 4, 2004, SpaceShipOne climbed to a record altitude of 377,591 feet (71.5 miles) and clinched the $10 million Ansari X Prize, awarded to the first private team to reach space.

Development costs of the craft were $25 million, fronted entirely by Allen.

Caption by / Photo by Virgin Galactic/Getty Images
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