Making Progress: Relativity’s Terran R, Rocket Lab’s Neutron, and PLD Space’s Miura 5
While Starship’s test program has dominated headlines, three other launch vehicle developers, Relativity Space, Rocket Lab, and PLD Space, have quietly announced significant testing milestones as they race toward debut flights later this year.
Relativity Space: Terran R moves into qualification
Relativity Space’s medium-to-heavy lift Terran R rocket has entered a critical phase. The vehicle features a reusable first stage powered by 13 Aeon R methane/LOX engines and an expendable second stage with a single Aeon V vacuum engine.
The first stage qualification article has been moved to a dedicated test stand in the company’s factory parking lot, where it has begun pressurized tank testing. These tests subject the tanks to operational pressures combined with mechanical loads that simulate flight conditions, with repeated cycles designed to validate long-term durability for reusability.
Meanwhile, the second stage has arrived at NASA’s Stennis Space Center in Mississippi for hotfire testing. Installation of a large flame diverter and access platform is underway on the test stand.
On the engine front, all 13 Aeon R engines for the first flight have completed acceptance testing, and acceptance testing has now begun on the Aeon V upper stage engine.
At the launch site, LC-16 at Cape Canaveral, propellant tanks have been installed, cranes are operational in the horizontal integration facility, and lightning protection towers are under assembly. Substantial integration, ground testing, and regulatory work remain before the first flight, still targeted for later this year.
Rocket Lab: Neutron engine completes full-duration burn
Rocket Lab’s medium-lift Neutron rocket passed a major milestone with the completion of a full-duration burn test of its vacuum-optimized Archimedes engine (AVac). The AVac produces approximately 1.2 times the thrust of the sea-level version and stands roughly 2.5 meters taller thanks to its extended nozzle, optimized for vacuum conditions.
The ground test used a shorter “stub skirt” configuration without the full nozzle extension to avoid flow separation risks at sea level, the full nozzle will be installed on the flight upper stage. The test demonstrated core engine performance across the full mission duration.
Neutron’s unique architecture features a payload fairing integrated with the reusable first stage. With the Archimedes engine now validated for full-duration operation, Rocket Lab is targeting the first Neutron flight for Q4 2026, following some earlier hardware setbacks that included the loss of flight-use components earlier this year.
PLD Space: Miura 5 completes tank testing
Spain’s PLD Space has achieved tank testing completion for both stages of its Miura 5 small-lift orbital rocket. The tests verified pressurization stability under nominal conditions, validated avionics and flight software interfaces, and confirmed the operation of pressurization and venting systems.
Miura 5 is a two-stage kerosene/LOX vehicle that will initially fly in expendable configuration. PLD Space is already planning a Block 1.2 variant that will add first-stage reusability, and a longer-term “Miura Next” family that could include multi-core configurations for super heavy-lift applications.
First flight hardware for Miura 5 is now in production, building on qualification articles manufactured in late 2025. The debut flight remains targeted for later this year.
A busy year for new launchers
The parallel testing campaigns from three different companies on three continents underscore the growing diversity of the global launch vehicle sector. While the headline-grabbing Starship program continues its development, Terran R, Neutron, and Miura 5 each represent distinct market niches, from medium-to-heavy lift to small orbital launch, that could reshape the commercial launch landscape if their debut flights succeed in the months ahead.
Clark – 1ban.news