Stratolaunch Systems announced another major milestone in the Stratolaunch program. Touted as the largest plane in the world (as measured by wingspan), in its latest series of taxi tests the Stratolaunch aircraft stormed down the runway reaching the maximum speed of 90 mph, thus edging closer to its first flight. The announcement came just days after the company founder’s Paul G. Allen’s passing (October 15, 2018).

In a video published on YouTube on October 18, 2018, Allen’s brainchild – Stratolaunch Systems – revealed it had performed a series of medium-speed taxi tests at its base of operations at Mojave Air & Space Port in Mojave, California (U.S.), during which, the Stratolaunch aircraft reached a maximum speed of 90 mph (145 km/h, 79 knots).



The Stratolaunch plane was first rolled out to begin ground and flight tests in May 2017. By the end of the year, in December 2017, the aircraft fired up its six Pratt & Whitney turbofan engines to complete its first low-speed taxi test. Traveling down the runway, the aircraft reached a maximum speed of 28 mph (45 km/h, 25 knots). These tests were the first time the plane taxied under its own power.

By the end of February 2018, the company revealed that in a series of medium-speed taxi tests, the Stratolaunch plane was able to reach a top speed of 46 mph (74 km/h, 40 knots). “The primary purpose of the activity was to evaluate updates made to the steering and primary braking systems. We are excited to report all objectives of this test were achieved,” company spokesperson Alex Moji said in a February 26, 2018, email to SpaceNews. “The data collected will be used to evaluate and update our flight simulator for crew training.”

Stratolaunch Systems has not officially announced a schedule for future tests or a date for the aircraft’s first flight. Various published reports indicate the plane’s maiden flight will take place sometime in 2019. For now, it is likely that more taxi testing at speeds approaching those required for takeoff are planned.

How it works

The Stratolaunch program is a new air launch system that will use its aircraft as a fully reusable, mobile launch platform. The air launch system will allow to lower fuel costs by ferrying payload rockets to high altitudes before launching them into the low Earth orbit. One of the main advantages is that it will be capable of deploying launch vehicles to multiple orbits and inclinations on a single mission.

In total, the company will use four different vehicles to launch satellites: the Pegasus rocket, capable of carrying small payloads into the low Earth orbit; a Medium Launch Vehicle (MLV) with a payload capacity of 7,500 lbs (3,400 kg); a much heavier Medium Launch Vehicle - Heavy with a payload capacity of 13,200 lbs (6,000kg); and the Stratolaunch space plane. The family of launch vehicles is scheduled to begin regular service to orbit in 2020.

Technical specs

Built for Stratolaunch Systems by U.S. aerospace company Scaled Composites, the aircraft is 238 feet (73 meters) long and has a tail height of 50 feet (15 meters). Its wingspan, stretching 385 feet (117 meters), is the largest of any plane ever assembled, according to the company.

The aircraft is powered by six Pratt & Whitney (PW4056) turbofan engines, used on Boeing 747s, and can undergo mission times totaling 10 hours. As to its range and lift capacity, the Stratolaunch has an operational range of 1,000 nm (1,852 km); a maximum takeoff weight of 650 tons (589,670 kg); and a payload capacity of over 500,000 lbs (226,796 kg), all enabled by its all-composite structure.

How about booking a… satellite launch?

Stratolaunch Systems says its goal is to provide “affordable, routine, airline-style access to space”. "Whatever the payload, whatever the orbit, getting your satellite into space will soon be as easy as booking an airline flight," Stratolaunch CEO Jean Floyd was quoted as saying by Popular Mechanics.

Those who cannot wait can already apply for a launch by fill out a form on the company’s website (, indicating their payload’s mass and preferred launch date. Though we would advise to at least wait until the space plane passes its flight trials.

Stratolaunch Systems was founded in 2011 the late American entrepreneur, Paul G. Allen, the co-founder of Microsoft with Bill Gates.  Initially, the Stratolaunch plane was designed to carry cargo, however, the company recently announced it has ambitions for a variant that would be capable of transporting crew. These ambitions were on the company’s founder’s mind from the start.