Almost Everything You Need to Know About the Stratolaunch

Stratolaunch, the world's largest aircraft is an engineering marvel.
John Loeffler
Stratolaunch Systems

Stratolaunch is one of the world's most unique and interesting aircraft ever created. In the works for over a decade, it has had its literal highs and lows over the years. 

After years of speculation of its future after the death of its founder, Microsoft's Paul Allen, it has found something of a second wind in recent years. 

Let's take a close look at this amazing piece of engineering. 

What is Stratolaunch?

The Stratolaunch Carrier, also known as "Roc", was originally designed and built by Scaled Composites and is the world's largest aircraft by wingspan. Its nickname comes from the myth of the Roc, a gigantic legendary bird, said to be able to carry off elephants, and mentioned in the collection of Arabic tales, The Thousand and One Nights.

Designed to carry air-launch-to-orbit rockets, the aircraft was first announced in 2011 but has since changed ownership, and has pivoted the main focus o the aircraft for hypersonic technology.  

Stratolaunch Carrier, according to the company, is designed to be a “mobile launch platform that will enable airline-style access to space that is convenient, affordable, and routine. The reinforced center wing can support multiple launch vehicles, weighing up to a total of 500,000 pounds (226.7 tons).”

what is stratolaunch
Source: Stratolaunch

In other words, this isn’t your typical airplane. The goal for the Carrier is to provide an alternative launch platform for satellites, other than rockets like SpaceX’s Falcon 9 or SpaceX’s Falcon Heavy rocket—which had its first successful test flight back in 2019.

Its first flight, in 2019, consisted of a two-and-a-half-hour test flight over the Mojave desert.

The Stratolaunch Carrier itself has the largest wingspan of any aircraft on Earth at 385 feet (117.3 meters), wider than a football field, including the endzones with almost two dozen feet to spare. The plane has two fuselages, each with its own cockpit—though only one is needed to fly—6 Pratt & Whitney engines, usually found on Boeing 747s, and 28 wheels for its landing gear.

Each of her 6 engines is capable of pumping out 56,750 pounds (252.4 kN) of thrust per engine. The aircraft also includes many of the avionics, flight controls, landing gear, and other systems also found on Boeing 747-400s. 

The Stratolaunch's controls include 12 cable-driven ailerons powered by hydraulic actuators, split rudders, and horizontal stabilizers on twin tail units. The aircraft's unique wing(s) has 14 electrically signaled, hydraulically actuated trailing-edge split flaps that also act as speed brakes. The hydraulic system and actuators, electrical system, avionics, pilot controls, and flight deck are, reportedly from donor B747-400s.

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From the ground to the top of the vertical tail, the aircraft stands at 50 ft (15.2 meters) and measures 238 ft (72.5 meters) from its nose to tail. It can also carry an additional 550,000 lbs (250,000 kg) of payload, with up to three rockets under the wing toward the center of the plane. 

The ultimate goal of the project is to normalize access to low-Earth orbit (LEO) that would allow for more organizations looking to either use satellite technology or explore space. The aircraft is estimated to have a range of 2,000 nautical miles (3,704 km), allowing the Stratolaunch Carrier to deliver payloads to multiple orbits from various places around Earth. 

"Opening up access to LEO will deliver many benefits," Paul Allen explained back in 2016. "For example, we could deploy more satellites that would enable a 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."

"As always, space remains an unforgiving frontier, and the skies overhead will surely present obstacles and setbacks that must be overcome," Allen added. "But hard challenges demand fresh approaches, and I’m optimistic that Stratolaunch will yield transformative benefits – not only for scientists and space entrepreneurs but for all of us."

stratolaunch enines
Close up of Stratolaunch's engines. Source: Stratolaunch

Rockets with orbital payloads will be mounted to the center wing of the aircraft, which will then be flown to an altitude of around 35,000 feet (10,668 meters).  At that altitude, the rocket will be released and it will fire, continuing on its way into orbit under its own power.

“It's so huge, it seems like it shouldn't be able to fly," aerospace and launch photographer for Jack Beyer told CNN.

“People are interested in the first flight of Stratolaunch because they want to see the future," he added. "It's the same reason why people tune in each year to watch the Apple keynotes. People want to see what's next.”

Now under new ownership, Stratolaunch as a company shifted focus to a hypersonic and aerospace aircraft carrier company. "Roc" will act as the main "mobile, multi-vehicle launch platform."

The idea, as the company website states are to make hypersonic testing more routine, "the Stratolaunch Carrier is designed to eliminate technical and logistical barriers that the hypersonics market faces today."

Prospective clients will, once the aircraft is fully operational, be able to choose a date of launch from those available for a particular year. Clients will either be able to have exclusive use of the "Roc" or choose to "rideshare". 

Another advantage will be the ability to choose from a range of U.S. runways for ground-based launches. "Our air-launch system allows us to avoid hazards like bad weather and conflicting fixed-range launch schedules (which often result in costly delays or cancellations). Rain or shine, Stratolaunch gets your payload launched on time," explains Stratolaunch.

To date, Stratolaunch plans to run 12 missions a year but will require booking several months in advance. This gives them enough time to prepare the payload but will allow institutions come as close as they can to "booking a seat on a flight," as for jetliners. 

When was Stratolaunch's first flight?

The world’s largest airplane, Stratolaunch, successfully took to the skies for the first time on April 13, 2019, in a two-and-a-half-hour-long test flight over the Mojave desert, marking a major aviation milestone.

Stratolaunch took off just before 7 AM PDT from the Mojave Air Space Port (MASP), achieved a maximum speed of 189 mph at an altitude of 17,000 feet (5,182 meters). The test flight was meant to test the aircraft’s performance and handling, eventually touching back down at MASP.

“What a fantastic first flight,” said Stratolaunch CEO Jean Floyd. “Today’s flight furthers our mission to provide a flexible alternative to ground-launched systems. We are incredibly proud of the Stratolaunch team, today’s flight crew, our partners at Northrup Grumman’s Scaled Composites, and the Mojave Air and Space Port.”

stratolaunches wheels
Source: Stratolaunch

According to Stratolaunch Systems, the results of the test flight included, “a variety of flight control maneuvers to calibrate speed and test flight control systems, including roll doublets, yawing maneuvers, pushovers and pull-ups, and steady heading side slips” as well as “simulated landing approach exercises at a max altitude of 15,000 feet mean sea level.”

Is the Stratolaunch still flying?

With the passing of Paul Allen back in 2018, there were rumors that the Stratolaunch would be indefinitely grounded. This, despite its very promising initial test flight earlier the same year.

Also nicknamed "Roc," Stratolaunch was, as previously discussed, originally designed and built for Stratolaunch by a subsidiary of Northrop Grumman, called Scaled Composites. Following the passing of Paul Allen, the project was compared to Howard Hughes' "H-4 'Spruce Goose," an ill-fated flying boat project that never hit the skies.

A unit of Paul Allen's privately held company, Vulcan Inc was reported as exploring the possible sale of Stratolaunch’s assets and intellectual property. However, after several years of tense waiting for Stratolaunch fans, she took to the air for a much-awaited second flight in April 2021. 

Earlier that year, new ownership of the company steered Stratolaunch away from its original vision as a space payload launcher and in a different direction: namely, towards the increasing demand for hypersonic flight testing platforms.

Though it's still in its testing phase, the "Roc" dwarfs the world's largest fully operational cargo plane, the Antonov An-225, with its wingspan of 290 feet (88 meters).  

Its second flight, like its first, took place over the sands of the Mojave airstrip. The "Roc" took off on April the 30th, 2021 after weeks of social media teaser footage of the "Roc" taxiing and being prepared for flight testing. 

stratolaunch second liht
Source: Stratolaunch

The second flight was originally due to take place on April 19, though this was delayed due to inclement weather. Prior to the launch of the "Roc", a Cessna Citation jet was sent up as a chase plane.

After the successful completion of "Roc's" second test flight, Stratolaunch posted on social media that "all results are as expected." 

As already mentioned, the aircraft was originally designed to launch payloads into space but has since shifted its focus to hypersonic jet testing. With the fierce competition in space payload delivery spearheaded by companies like SpaceX — which has more than a hundred launches under its belt — and Rocket Lab, which also aims to fly with reusable rocket boosters, the logic of this shift in focus is sound. 

The global hypersonic missiles market is expected to grow by 101 million dollars between 2020 and 2024, and the US Department of Defense recently announced hypersonics as one of its top priorities for modernization. With the "Roc's" second flight now under its belt, it is making some strong strides to becoming something an emerging giant in this sector in the not too distant future. 

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