Even after flying 140 different types of aircraft, the chief pilot on Virgin Galactic's successful powered-spaceship test Thursday (April 5) says being at the helm of the VSS Unity was "something else."

"This is a major milestone in our flight test program," says David Mackay in a new video from Virgin Galactic posted on YouTube. "When the rocket motor is lit, that's when it really comes alive. We've been gliding it [the spacecraft] so far, but really, what it's designed to do is go into space."

The flight of VSS Unity yesterday (April 5) was the first powered test of any Virgin vehicle since the fatal crash of SpaceShipTwo VSS Enterprise on Oct. 31, 2014. [Virgin Galactic's VSS Unity Spaceliner in Pictures]

The new flight saw VSS Unity drop as planned from its WhiteKnightTwo carrier aircraft at an altitude of 50,000 feet (15,000 meters), roughly 20 miles (32 kilometers) north of the Mojave Air and Space Port in California. The ship was piloted by Mackay and Mark "Forger" Stucky. They pushed the ship to a maximum altitude of 84,271 feet (25,686 m) and a top speed of Mach 1.87 before completing a safe touchdown at the spaceport's runway.

Mackay's video shows a behind-the-scenes look at his preparations for the flight, starting when he pulls his pickup truck up to the space port just as dawn is breaking. He is shown going into the locker room, carefully dressing in his flight suit and writing in a notebook as his narration plays.

"My first memory of what I wanted to do was be a pilot," Mackay recalls. "That's because I was brought up in an area of Scotland where a lot of low flying was taking place. I would see aircraft flying at high speed, at very low altitude, over my village on a daily basis. So, as a young boy, it looked extremely exciting, and I wanted to be a pilot."

Mackay has been flying since 1977, first with the U.K. Royal Air Force and now with Virgin Galactic. The former test pilot has logged more than 14,000 hours in the air in many dozens of aircraft types.

"It maybe takes a certain sort of character to become a test pilot," Mackay says in the video. "It's someone who not just enjoys flying, but is really interested in the science and the engineering behind it and what makes a good aircraft, or what makes a bad aircraft, and why. It's a desire to not just fly, but to understand them [aircraft] at a deeper level and to try and improve them."

The video then shows the teams for both VSS Unity and WhiteKnightTwo walking on the runway. As a close-up of the spacecraft appears, Mackay explains that the feeling at that moment is similar to being in a big sports game. "You've trained, and you feel fit and ready and prepared, and you know your tactics. So, you're not, you know, scared, but you're not completely relaxed either. You're kind of keyed up and ready for it."

Virgin Galactic's second SpaceShipTwo, the VSS Unity, performed its first rocket-powered test flight over California's Mojave Desert on April 5, 2018. The test flight did not aim to reach space. (Image credit: Virgin Galactic/www.MarsScientific.com & Trumbull Studios)

Mackay's narration ceases during the rebroadcast of the spacecraft's flight. The video not only shows dramatic shots of VSS Unity with the curvature of Earth below, but also features people on the ground looking to the sky for any sign of the flight.

There's a quick glimpse from the inside of the cockpit, and then, at last, VSS Unity fires its engines as planned, moments after dropping below WhiteKnightTwo's belly. A dramatic shot from the spacecraft's hull shows the ground below, obscured by a lot of fire from its exhaust. The sun reflects off the spacecraft against the black view seen at high altitudes, where the air is very thin. On the ground, the white streak of the spacecraft shows against blue sky.

When VSS Unity lands, the crowd erupts into riotous cheering. "I'm lucky enough to fly many performance aircraft," Mackay says as he is shown approaching the crowd. "But this is something else."

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