Rocket Lab launches hypersonic scramjet vehicle for the US military

Rocket Lab launched a scramjet-powered hypersonic vehicle for the U.S. military to suborbital space on Friday (Feb. 27).

The company's HASTE suborbital rocket lifted off Friday at 7 p.m. EST (0000 GMT on Feb. 28) from Rocket Lab's Launch Complex 2 on Wallops Island, Virginia, carrying a hypersonic demonstrator called DART AE to the final frontier.

That was a two-day delay; the mission was originally supposed to fly on Wednesday (Feb. 25), but Rocket Lab called off that attempt "due to out-of-bounds launch commit criteria."

DART AE is a 10-foot-long (3 meters) technology demonstrator built by the Australian aerospace company Hypersonix. It's "designed to validate advanced propulsion, materials, sensors and guidance systems at real hypersonic flight conditions," the company said in a statement earlier this month.

Hypersonic vehicles travel at least five times faster than the speed of sound. They also tend to be highly maneuverable, making them tougher to intercept than ballistic missiles — and therefore quite attractive to the militaries of the U.S. and other nations.

Friday's mission, which Hypersonix called "Cassowary Vex," was the first for DART AE. The demonstrator is powered by Spartan, the company's 3D-printed scramjet engine.

Scramjets inject fuel into air that's flowing through them faster than the speed of sound. That's the main difference between a scramjet and a ramjet, which deals with slower-moving air. ("Scramjet" is short for "supersonic combustion ramjet.")

Hypersonix says they use a propellant that makes their scramjet cleaner than most. "Unlike conventional scramjets powered by kerosene, SPARTAN uses hydrogen, producing zero CO2 emissions and offering a usable, low-maintenance solution for a range of high-speed defense and aerospace missions," the company said in the same statement.

DART AE flew Friday for the Defense Innovation Unit (DIU), a branch of the U.S. military devoted to adapting commercial technology for national security uses. It was HASTE's second DIU mission, following a November 2025 launch that Rocket Lab called "Prometheus Run."

As its name suggests, HASTE is a modified, suborbital version of the 59-foot-tall (18 m) Electron, Rocket Lab's workhorse orbital launcher. ("HASTE" stands for "Hypersonic Accelerator Suborbital Test Electron.")

HASTE is a testbed, providing "reliable, high-cadence flight test opportunities needed to advance hypersonic and suborbital system technology development," according to Rocket Lab's website.

The suborbital rocket debuted in June 2023. Friday's mission, which Rocket Lab called "That's Not a Knife," was its seventh flight to date. DART AE required a 14.1-foot-long (4.3 m) payload fairing — the longest custom-built HASTE fairing yet, according to Rocket Lab.

"That's Not a Knife" was over quickly: HASTE's job was done about 2.5 minutes after liftoff, at which point Rocket Lab stopped showing live views from the rocket (at the customer's request). "Cassowary Vex" continued for a spell, however, with DART AE seeking to notch some unspecified milestones.

Electron, meanwhile, now has 75 launches under its belt.

Editor's note: This story was updated at 4:25 p.m. ET on Friday with news of launch success.