The world’s largest aircraft, boasting six engines, two fuselages and a wingspan broader than a football pitch, is growing ever closer to its first flight.
Stratolaunch, the brainchild of Microsoft co-founder Paul Allen, is nearly more than double the width of a Boeing 747 and with a wingspan of 117 metres surprasses even Howard Hughes’ famous Spruce Goose (97.5m). The aircraft has been in development since 2011 and after being rolled out of its custom-made hangar last year, has just completed its first high-speed taxi test.
The Stratolaunch, weighing 580 tons and carrying six Pratt & Whitney engines on 28 wheels, trundled down the runway in Mojave, California, reaching a top speed of 46mph. Further development will hopefully allow the potential space rocket carrier to take to the skies some time next year.
What is the Stratolaunch?
It will be a launch vehicle for space rockets. The gap between its two fuselages is designed to carry rockets up to the cruising altitude of a standard commercial aircraft (say, 36,000 feet) before they are sent on their own way.
Using the Stratolaunch instead of a ground launch pad will save money in fuel and reduce the cost of sending cargo into space. It also means that the rocket launches will be above many of the weather issues that can affect launchpads on the ground.
The aircraft will have a range of 2,000 nautical miles, similar to that of an Airbus A319. Its engines, along with some of its landing gear and flight deck, were “cannibalised” from two out of service Boeing 747s to save on development costs.
Captured new video of @Stratolaunch plane as it reached a top taxi speed of 40 knots (46 mph) with all flight surfaces in place on Sunday. The team verified control responses, building on the first taxi tests conducted in December. pic.twitter.com/OcH1ZkxZRA— Paul Allen (@PaulGAllen) February 26, 2018
Who is behind the project?
Microsoft co-founder Paul G Allen and Scaled Composites founder Burt Rutan founded Stratolaunch Systems Corporation in 2011. The pair previously collaborated on SpaceShipOne, the first privately built aircraft to achieve supersonic flight and one with sub-orbital space flight capacity.
Allen, who was obsessed with rockets as a child, left Microsoft in 1982 because of health reasons but retained a sizeable stake in the company. He has a reported net worth of $21.4billion (£15.3bn).
He wrote in 2016: "Opening up access to LEO (low earth orbit) will deliver many benefits. For example, we could deploy more satellites that would enable better understanding of why our weather patterns are changing and help increase agricultural productivity.
"And, we could study atmospheric chemistry more closely to better study and mitigate climate change.
"But none of this will happen as quickly without exploring new, flexible and streamlined ways to send satellites into orbit."
He said in another interview last year, as reported by the Washington Post: “I would love to see us have a full reusable system and have weekly, if not more often, airport-style, repeatable operations going.”
It was Allen and Rutan’s SpaceShipOne, which won the Ansari X prize, which laid the blueprints for Virgin Galactic’s plans to take travellers to space, after Allen licensed the technology behind the spacecraft to Sir Richard Branson’s operation.
“Flying test pilots, I understand," Allen said. "But paying-man-on-the-street-type passengers, I wanted to leave that to someone else."
And then what?
The next piece of the puzzle, which Allen and Rutan are said to be working on, is a reusable spacecraft, nicknamed Black Ice.
According to the Washington Post, which published an extract from The Space Barons: Elon Musk, Jeffrey P Bezos and the Quest to Colonise the Cosmos, a book by Christian Davenport, Black Ice would be able to launch into space from anywhere in the world, as long as the runway could accommodate the Stratolaunch, then be capable of flying into space and returning to the runway, ready to fly again.
"You make your rocket a plane," Jean Floyd, Stratolaunch System’s chief executive, said. "So, you have an airplane carrying a plane that's fully reusable. You don't throw anything away ever. Only fuel."