Defense aviation company Hermeus has announced the development of Ramjet-X, its next-generation ramjet propulsion test vehicle capable of carrying test payloads to high Mach speeds.

The company said Ramjet-X, designed to launch mid-flight from a carrier aircraft, offers the key advantages of competitive high-Mach test platforms while keeping costs low enough for a wider range of mission profiles.

Pre-flight testing of Ramjet-X is already underway, with its first official prototype test flights expected in 2027.

Ramjet-X Will Launch Mid-Flight from Quarterhorse

Most conventional jet engines can’t achieve supersonic speeds without dumping raw fuel into an afterburner and literally rocketing past the sound barrier. To travel at high Mach speeds without relying on rocket-style propulsion, engineers have turned to ramjet engines.

While ramjets are effective, they rely on the high-speed influx of air to operate. This limitation means aircraft equipped with this type of propulsion must be propelled to higher speeds by another craft or booster rocket before they can engage.

In an email to The Debrief, a Hermeus spokesperson explained that current options often rely on “large and expensive” boosters that are discarded after each test. Conversely, Ramjet-X relies on the company’s reusable aircraft to reach launch velocity.

“Ramjet-X is designed to be carried by Quarterhorse, which provides the speed and altitude required for deployment,” the company told The Debrief.

The company could not disclose what speed Quarterhorse must achieve before it can launch Ramjet-X. However, the spokesperson did note that the launch craft is designed to return to home base for future missions.

When asked about Ramjet-X’s specific operating velocity once it disengages from Quarterhorse and engages its ramjet propulsion system, the company could only say the vehicle will operate at “High-Mach speeds.”

Conventional ramjets use a combination of high-velocity air and fuel to achieve extreme velocities. Hermeus said they cannot disclose specifics about Rocket-X’s fuel requirements.

Mission Profiles and Repeatable Architecture

Because of the sensitive nature of potential future missions, Hermeus was cautious about sharing specifics of any planned missions. The company also couldn’t provide technical details on what a typical mission profile might look like.

However, a Hermeus spokesperson told The Debrief, the vehicle’s architecture “allows customers and partners to integrate payloads, sensors, communications and computer systems, autonomy, material samples, propulsion technologies, and other experimental hardware and software onto Ramjet-X for testing in representative sustained high-Mach conditions.”

Hermeus also highlighted the potential cost savings of a “repeatable platform, launch architecture, and flight-test infrastructure,” designed to dramatically lower costs without sacrificing versatility or reliability.

“Instead of relying on a large dedicated expendable booster to accelerate the test vehicle into its ramjet operating regime, the launch aircraft provides much of that energy and then returns to fly again,” the company told The Debrief. “This architecture allows Hermeus to fly more by reducing the cost of expendable launch hardware.”

“High-speed flight testing is extremely expensive, and you don’t get many shots at it,” Hermeus CEO Zach Shore explained.

“Another Order of Magnitude Reduction”

Hermeus said specific unit costs are not currently available. However, they said a projected cost per minute of high-Mach test time “is in the low $100k’s per minute.” For comparison, the company highlighted the historic and current costs of high-Mach flight testing.

“Most of the below comparisons are rocket-based but will give you an idea how costly high-Mach tests are and why Ramjet-X will fundamentally change the equation,” Hermeus told The Debrief.

Older examples include NASA’s X-43, which achieved around 21 seconds of high-Mach flight, and the Air Force’s X-51, which achieved around 350 seconds. Hermeus said both multi-year efforts cost around $450 million each in today’s dollars.

Current options include rocket-powered test flights aboard Rocket Lab’s HASTE, which Hermeus said run $10-20 million each, “not including the expendable cruise or glide vehicles.” The company also pointed to Stratolaunch Talon-A missions.

“Even though fully reusable, (they) are $10-12m per flight for a few min of on-condition time,” the company told The Debrief.

Conversely, Hermeus said its current projections of less than a million per minute offer potential customers “another order of magnitude reduction in the problem that matters most.”

“Ramjet-X is being designed around simplified manufacturing, rapid production, and expendability in meaningful quantities rather than the traditional model of building a small number of highly bespoke high-speed test articles as was done in other high-speed airbreathing flight test programs like X-43 and X-51,” the company told The Debrief. 

Development of Ramjet-X is already well underway

When detailing the newly announced Ramjet-X’s benefits, Shore noted that their system gives them a way to place new systems into sustained high-Mach environments “without building an expensive one-off test program every time.”

“Bringing speed, sustained flight, and scalability all into one system lowers the barriers to gathering extremely valuable data from these conditions and accelerates programs for both us and our customers,” the Hermeus CEO explained.

When announcing Ramjet-X, Hermeus said the vehicle’s ramjet engine is already undergoing extensive testing at its Florida-based HEAT facility. Future tests will occur at the company’s California headquarters, with the first flight tests planned for 2027. 

Christopher Plain has spent the last six years as Associate News Editor and Head Science Reporter at The Debrief. Follow and connect with him on X, learn about his novels at plainfiction.com, or email him at christopher@thedebrief.org.

Private space launch services company Rocket Lab has unveiled its GHOST (Global Hypersonic & Orbital Spaceport Technology) self-contained mobile launch system, capable of placing payloads in orbit or enabling suborbital launches from virtually anywhere on Earth.

Designed to accommodate the company’s Electron and HASTE rockets, the company said GHOST’s “launch-anywhere, launch-anytime” capability can support multi-launch flight campaigns for commercial applications. Rocket Lab said the system’s versatility also offers benefits for “critical” national security missions.

GHOST Private Space Launch System Fits Into Standard Shipping Containers

In science fiction, rockets can launch spacecraft from just about anywhere. However, until recently, most launches have occurred at dedicated, government-owned and operated facilities. Even the relatively recent proliferation of private launch services companies promising cheaper, faster alternatives hasn’t reduced the need for a launch facility specially designed to send rockets into orbit.

Now, Rocket Lab says the company has created an all-in-one launch solution called GHOST that can accommodate rocket launches from seemingly anywhere.

For example, when announcing the formal unveiling of GHOST, the company said the entire system can be packaged in standard shipping containers. This includes all the hardware to launch complete rockets and the ground support infrastructure needed to complete single-launch missions or multi-launch campaigns.

Perhaps most critically, the system can be shipped to any destination for customized launch services worldwide. If the already scheduled real-world inaugural launches prove the claims, that launch-location versatility could give Rocket Lab a technological edge over its private space launch competitors.

Two New Alaska Launch Pads Will Provide the System its First Real-World Test

When unveiling GHOST, Rocket Lab also announced its first launch site. Dubbed Rocket Lab Complex 4, GHOST’s new home will be at the Pacific Spaceport Complex at Kodiak, Alaska. The company said this inaugural site will include two distinct launch pads for “high-frequency launch campaigns.”

The new site will join the already operational Launch Complex 1 in New Zealand and Launch Complexes 2 and 3 in Virginia. The company said that taken together, Rocket Lab now controls six total launch pads “across two hemispheres.” Along with its reported mobility, the company emphasized GHOST’s ability to accommodate both Electron and HASTE.

“GHOST delivers a dual-launch capability across new locations, allowing Rocket Lab to expand the mission profiles of both vehicles and meet increasing international demand for orbital and suborbital sovereign launch capability,” the company explained.

Rocket Lab also said that the mobile launch platform is “purpose-built to support responsive launch needs and time-critical national security missions, enabling rapid site activation and simultaneous launch possibilities.”

The company expects to conduct its first GHOST-supported launch from Launch Complex 4 in 2027, including launches announced in July for the U.S. Space Force.

“The size and scale of this contract reflects the Space Force’s confidence in our ability to meet their urgent national security demands with speed, responsiveness, and scale, and we’re proud to provide the high-frequency launch capacity required to keep the U.S. ahead of global threats,” company CEO Sir Peter Beck said at the time of the announcement.

“Leading the Field in Small Launch for Missile Defense and National Security”

After noting that Rocket Lab has been “leading the field in small launch for missile defense and national security for years,” Sir Beck heralded GHOST’s seemingly sci-fi-sounding ability to launch a rocket into space from virtually anywhere in the world as another example of the launch service reliability and repeatability.

“Creating GHOST is about packaging that up into a deployable system that can serve the world’s most important programs from wherever those missions need,” Sir Beck said. “Whether it’s for missile defense and deterrence, or opening up more trajectories, orbital missions, and sovereign launch capabilities in allied nations, GHOST is the answer to launching anywhere, anytime, and without compromise.”

Christopher Plain is a Science Fiction and Fantasy novelist and has spent the last six years as Associate News Editor and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him at christopher@thedebrief.org.