Ben Cooper/LaunchPhotography.com
Relativity Space has shared key findings from Terran 1’s ‘Good Luck, Have Fun’ (GLHF) test flight last month, and has deemed 3D printed rockets as ‘structurally viable.’
The rocket, 85% 3D printed by mass, crossed the 100km Karman line and passed the highest loading conditions at Max-Q, despite encountering an anomaly at Stage 2 which meant the engine did not meet full thrust.
Among the other findings from the GLHF test flight were:
- Relativity’s nine 3D printed, Lox/methane, regen-cooled Aeon 1 engines ignited several seconds before T-0 and reached their full 207,000 lb of combined thrust through their nominal startup sequence prior to release at T-0.
- Data indicates nominal performance of 3D printed structures throughout the mission, in alignment with proto-qualification structural testing performed on the ground during Terran 1’s test campaign.
- The vehicle demonstrated excellent ascent performance through Max-Q and demonstrated exceptional guidance, navigation, and control performance during liftoff and Stage 1 burn, including through strong upper-level winds near the Max-Q timeframe.
- After Stage 1 Main Engine Cutoff (MEC), at T+163 seconds and approximately 7,450 km/hr velocity, our in-house designed stage separation system performed as expected to cleanly separate Stage 1 and Stage 2.
- Approximately T+168 seconds into flight, the Aeon Vac engine telemetry diverged from expectations and the engine did not reach full thrust. There is an investigation underway, and preliminary findings on root cause include:- The engine valves opening slower than expected, impacting pressures in the system and the timing of propellant reaching the thrust chamber assembly (TCA) and gas generator (GG) during the start sequence.- When spin-start power was applied to the turbines, the fuel pump generated pressure, as expected, but the oxygen pump did not, which also impacted pressure and timing of propellant reaching the TCA and GG during that start sequence. The data from the oxygen pump is consistent with a vapour bubble being present at the pump inlet.- Due to off nominal propellant pressure and timing, the GG did not light, and the engine did not reach full power.
- Despite not reaching full power, the vehicle demonstrated effective control performance via engine gimballing and the Reaction Control System (RCS). At T+191 seconds, Stage 2 reached space by crossing the 100km Karman line, and continued to gain in elevation coasting up to 134km.
Full details of Relativity's findings can be found here, while below we look at what comes next for Relativity.
Relativity Space
Rendering of Terran R launch.
Looking ahead, Relativity has announced it is shifting its focus to design, develop and produce its next generation Terran R launch vehicle.
Terran R is a medium-to-heavy lift reusable rocket that has been designed to meet customer’s needs for ‘disruptive, diversified launch capabilities in an underserved and quickly growing payload market.’ A two-stage, 270-foot-tall rocket with an 18-foot diameter and a 5-metre payload fairing, Terran R is being developed to send payloads into Low Earth Orbit (LEO), Medium Earth Orbit (MEO), Geosynchronous Transfer Orbit (GTO), and beyond. It will prioritise first stage reusability, with the capability of launching 23,500kg to LEO or 5,500kg to GTO, both with downrange landing, or up to a maximum payload of 33,500kg to LEO in expendable configuration. Terran R is expected to launch starting in 2026.
In revealing more details regarding the Terran R, Relativity has stated it is serving a signed customer backlog of 1.65 billion USD Launch Service Agreements (LSA) and is in an additional several billion dollars’ worth of active customer LSA dialogue.
Each Terran R rocket requires approximately six times more 3D printing by mass than Terran 1. Initially, Terran R will use the same proprietary printed aluminium alloy as flown on Terran 1 with a focus on supply chain scaling, but a third-generation aluminium alloy designed for improved performance on orbital mission life beyond 20 reusable flights is in active development. Terran R will also use 3D printed Aeon R engines, which are designed to use liquid oxygen and liquid methane propellants, be highly reusable, and feature a uniquely high-pressure gas generator cycle driving two turbopumps.
Relativity has also stated that Terran R’s first stage will be equipped with 13 3D printed gas generator cycle Aeon R Lox/Methane rocket engines, each capable of 258,000b sea level thrust, while its second stage houses a single Lox/Methane Aeon Vac engine with 279,000 lb vacuum thrust.
Terran R’s production homebase will be in Long Beach, CA, at Relativity’s one million square foot headquarters which is home to its fourth-generation Stargate 3D metal printers. At production run rate from this single factory, the company estimates its ability to initially produce and fly more than 45 Terran Rs annually, with adaptive software-driven production infrastructure able to build more or less first or second stage components based on reuse rate and customer demand over time. Stage and engine testing for Terran R will take place at Relativity’s test facilities, located at NASA Stennis Space Center in Mississippi.
“Our first chapter as a company was to prove to the world 3D printed rockets were viable. We just did that with Terran 1. Our second chapter is to build the next great launch company with Terran R,” commented Relativity Space co-founder and CEO Tim Ellis. “Terran R is the most customer-centric next-generation launch vehicle. It is not a conventional rocket. This is a new breed of launch vehicle with the right payload performance, reliability, focus on speed of development, optimised reusability, focus on scalability of launch ramp rate, and ultimately cost reduction baked into the architecture design and our program plans from day one. Terran 1 was like a concept car, redefining the boundaries of what is possible by developing many valuable brand-new technologies well ahead of their time. Terran R is the mass-market, huge demand product that will be amazing precisely because it brings those 'concept car' developments into full maturity, enabling Relativity to become a disruptive, diversified provider in solving the glaring medium-to-heavy lift launch market gap for customers with a new vehicle faster than previously possible.”
“The entire Iridium team congratulates Relativity on a historic first launch, proving the viability of 3D printed rockets. As Iridium knows, being successful in space takes hard work, innovation and perseverance. We applaud their transition now to completing Terran R, which is better aligned with industry’s anticipated future launch requirements. We look forward to seeing Relativity’s continued success and the new possibilities they are bringing to the industry as a whole,” added Iridium CEO Matt Desch.
