Miranda test
Firefly Aerospace announced Nov. 28 the first test of its Miranda engine that will be used on the Antares 330 and MLV launch vehicles. Credit: Firefly Aerospace

WASHINGTON — Firefly Aerospace has conducted the first hot-fire test of a new engine that will power the company’s future launch vehicles.

Firefly announced Nov. 28 that it conducted the test of its Miranda engine at the company’s Texas test site. A company spokesperson said the test, performed at 65% power, was designed to validate the engine’s startup sequence.

The company plans to work its way up to a full-duration test in the coming months, running the engine for 206 seconds. Miranda uses liquid oxygen and kerosene propellants, generating 230,000 pounds-force of thrust.

Seven Miranda engines will power the first stage of the Antares 330, a new version of Northrop Grumman’s Antares rocket that the companies announced a partnership to develop in August 2022. It will replace the Ukrainian-built first stage previously used on Antares with Russian engines. The companies expect the Antares 330 to be ready for a first flight as soon as mid-2025.

A similar first stage, also using seven Miranda engines, will be used on another rocket, currently called the Medium Launch Vehicle or MLV. A new second stage will use a single vacuum-optimized Miranda engine. That vehicle, ready for a first launch as soon as late 2025, will be able to place up to 16,000 kilograms into low Earth orbit, versus the 10,000 kilograms of the Antares 330.

“Upgrading the first stage of Antares in parallel with developing the Medium Launch Vehicle enables our two companies to bring a new launch vehicle to market more rapidly while also reducing risk in the design process,” Scott Lehr, vice president and general manager of launch and missile defense systems at Northrop Grumman, said in a statement about the test.

Bill Weber, chief executive of Firefly, noted in the statement that Miranda was developed in just over a year. “Building on the legacy of Firefly’s rapidly developed Reaver and Lightning engines, Miranda is the fastest propulsion system we’ve built and tested to date,” he said, referring to the engines the company developed for its Alpha launch vehicle.

In an interview earlier this month, Weber said the schedule for the first MLV launch was driven by having the vehicle eligible for the National Security Space Launch (NSSL) Phase Three program in time to on-ramp to that program’s “lane one” for emerging launch vehicles. “We want to fly that mission in late ’25 so that we put ourselves in a position to qualify for the ’26 manifests in lane one,” he said. “So far, so good. We’re on track.”

Firefly is balancing work on Miranda, Antares 330 and MLV with increasing production of its Alpha launch vehicle. That rocket most recently launched Sept. 14 on the Victus Nox mission for the U.S. Space Force to demonstrate tactically responsive space. The next Alpha launch, scheduled for December, will place into orbit a Lockheed Martin satellite to test new antenna technologies.

Weber said Firefly is planning four Alpha launches in 2024, all of which have customers manifested, and at least six launches in 2025. He said the company’s current facilities could support the production of up to 24 Alphas a year, provided there is sufficient demand and that the company can turn around launches that quickly.

Firefly announced Nov. 10 that it closed a third tranche of a Series C round, bringing the total raised since February to $300 million at a pre-money valuation of $1.5 billion. “We’re capitalized and we’re funded for our foreseeable future,” Weber said.

The company is continuing to raise money despite what he described as one of the most difficult markets to do so in recent memory. There was renewed interest after the Victus Nox launch, he said, and expects more interest after the upcoming Alpha launch. “I think there are some good options out there for us.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...