Stratolaunch

The Future of Hypersonic Testing

An Auspicious Beginning

Paul Allen and Burt Rutan first collaborated on SpaceShipOne, the project that would eventually lead to the first crewed private spaceflight in 2004, and go on to win the $10 million Ansari X Prize. At first glance, it seemed like an unlikely duo; Paul Allen being the reclusive billionaire co-founder of Microsoft, and Rutan being the eccentric aerospace designer and founder of Scaled Composites. But the two would bond over their mutual love of space, and belief that it should be open to private investment.

The success of SpaceShipOne would eventually lead to The Spaceship Company, a joint venture between Burt Rutan's Scaled Composites, and Richard Branson’s Virgin Group, known today as Virgin Galactic. It would also result in a lesser known, but perhaps even more wildly ambitious joint venture between Allen and Rutan, Stratolaunch.

The Largest Plane Ever Flown

Roc, the nickname given to the behemoth after the legendary mythical bird, features a twin-fuselage design and the longest wingspan ever flown. At 385 feet (117 m), it surpasses even the Hughes H-4 Hercules flying boat of 321 feet (98 m). To give you a sense of scale, the wingspan is longer than an American football field, plus the endzones and then some.

The twin-fuselage, catamaran-style aircraft was originally intended to be a flying launchpad, its purpose to tow a rocket ship to cruising altitude before dropping it for its fiery ascent into space. About seven years after the initial announcement, and the construction of a 100,000 sq ft hangar in Mojave, Roc flew for the first time. Sadly, this flight took place a few months after Paul Allen’s death in late 2018. This would be the catalyst for a change in ownership, and a radically new direction for Roc.

A shift in strategy

Since its sale to private equity firm Cerberus Capital Management, Stratolaunch has repositioned itself as a provider of testing and development services to projects developing hypersonic air vehicles.

The company is now developing three vehicles to launch from Roc, with Talon-A as the initial focus. Talon-A is a reusable unmanned powered glider vehicle that uses a liquid fuel rocket motor to help it propel to speeds of at least Mach-6 after launch. It is 28 fleet long and has a wing-span of just over 11 ft. After completing about 1-minute of hypersonic flight testing, it's designed to land on a conventional runway.

It is equipped with various modular payload spaces to support a number of key flight test activities. Stratolaucnh goal is for the Roc to be able to carry multiple Talon-A sized vehicles at once. They are also working on a similar but larger vehicle called Talon-z, and a space plane called black ice, that could be configured to carry cargo and human passengers to orbit.

Stratolaunch is betting on the new hypersonic arms race, which means military investment into R&D for hypersonic vehicles. Talon-A, or a derivative thereof, could be used as a surrogate for hypersonic weapons that use a boost glide vehicle format, a technology both Russia and China claim to have. Fitted with sensors, Talon-A could provide critical data that will aid in bolstering defense against these weapons, and also enable us to develop more robust weapon systems ourselves.

Hypersonic Arms Race

Traditional ballistic missiles follow a parabolic trajectory, a predictable arc that goes up and down. It means they can be detected early in flight. Hypersonic glide vehicles work differently, they exploit physics, using drag and friction so they can fly in all directions like an aircraft, but at super fast speeds.

This makes them very difficult to detect until it's too late. By flying below the radar horizon, warning times will be shorter, and since they are meaneuaverale, it's difficult to know exactly where they are headed. Given these advantages, hypersonic glide vehicles are commonly depicted as a revolutionary new tool of war; Faster, less detectable and harder to intercept than currently deployed long range ballistic missiles.

Hypersonic Testing & The Future

The effectiveness of hypersonic weapon systems are still largely theoretical, but major powers like Russia, China and the United States have all bought into the belief that they are game-changing. Those in power believe that hypersonic weapons present significant challenges for defenders in terms of detecting and tracking incoming threats, as well as attempting to intercept them.

Roc will be a key partner for the government and defense contractors, enabling them to test new sensors and interceptors against real representative targets. Stratotlaunch recently received a contract from the Missile Defense Agency to supply a target that mimics certain hypersonic threats to support the development of new defensive capabilities. It's not clear whether the target it will provide to MDA will be an entirely new development or one based on an existing design the company has been working on, like the Talon-A. The company’s stated goal is to conduct the first flight test of one of these vehicles this year (2022).