Stratolaunch to expand Talon-A reusable hypersonic vehicle into missile-defence testing

Hypersonic developer Stratolaunch has received a substantial US government contract to expand testing of its reusable Talon-A prototype, including testing related to missile-defence initiatives. 

The US Missile Defense Agency (MDA), a bureau within the Pentagon, is providing Stratolaunch with $24.7 million to support additional development on the Talon-A programme, the company disclosed on 9 January.

The contract will help fund specialised modifications to a Boeing 747-400 passenger jet, which Stratolaunch will use as a carry vessel for the air-launched Talon-A. The deal will also see Stratolaunch begin flight operations outside its main base in the California desert.

“By enabling Talon-A launches from any airport capable of accommodating a 747, Stratolaunch is delivering on its commitment to provide its customers operational flexibility and global scalability,” says chief executive Zachary Krevor.

While Stratolaunch successfully completed the first powered flight of the rocket-propelled Talon-A in 2024, this was achieved using a highly-specialised and unusual mother ship aircraft called Roc.

Believed to be the largest aircraft currently flying anywhere in the world, Roc is a six-engined, dual fuselage, all-composite, over-wing design (registration N351SL) created by Scaled Composites as a purpose-built air-launch vehicle for Stratolaunch.

With a 117m (385ft) wingspan and 226,800kg (500,000lb) payload capacity, Roc is used as a so-called “captive-carry” platform, ferrying Talon-A aloft between its twin fuselages. When sufficient altitude is achieved, the Talon-A drops and ignites its single Ursa Major Hadley rocket engine.

In March 2024, a single-use Talon-A test vehicle used this method to achieve what Stratolaunch described as “high supersonic speeds approaching Mach 5”, with that mark being the generally agreed threshold of hypersonic flight.

The company is planning subsequent flights with other Talon-A examples to break the M5 hypersonic barrier.

However, the massive size and unique shape of the Roc limits its operations to ground facilities that can accommodate such a large aircraft. With that in mind, Stratolaunch is developing a second captive-carry aircraft using a 747.

The new MDA grant will support modification work on that jet, which Stratolaunch has already named the Spirit of Mojave. When complete, Stratolaunch says, the new captive-carry vessel will enable it to expand Talon-A flight capabilities “beyond the US western coast to a variety of global locations”.

“The test campaign portion of the project, targeted to occur in the fourth quarter of 2025, will demonstrate critical capabilities for testing advanced missile defence systems against the growing global threat posed by hypersonic weapons,” the company adds.

Stratolaunch has a goal of making hypersonic flight-testing more “reliable and routine”, and for Talon-A to be an affordable platform for testing developmental equipment and technologies supporting hypersonic flight.

However, with support from the Pentagon agency developing anti-ballistic-missile defences, Stratolaunch appears to be expanding its scope.

“Hypersonic threats are difficult to detect and counter due to their speed, manoeuvrability, low-altitude flight paths and unpredictable trajectories,” says Michael Kryzak, the MDA’s director of systems, targets and countermeasures.

With the Stratolaunch partnership, the MDA appears bullish on the prospect of using Talon-A as a mock threat vehicle to explore methods of countering inbound hypersonic missiles. “We are pleased to partner with Stratolaunch to test our defensive architecture against these potential threats,” Kryzak adds.

US adversaries Russia and China took an early lead in the race to develop functional hypersonic weapons, with Washington now seeking to catch up. In 2021, General Mark Milley, then-chairman of the joint chiefs of staff, described successful hypersonic tests by the Chinese military as a second “Sputnik moment” for the USA – referencing the 1957 Soviet low-orbit satellite that invigorated the US space programme and led to the Cold War’s space race.

The Pentagon has recently poured money into hypersonic development, funding research programmes in the defence industry, academia and with private start-up ventures like Stratolaunch and Hermeus.