Terran R Is Getting Closer To Its First Test Flight

Terran R Is Getting Closer To Its First Test Flight

Not long ago Relativity announced a significant revamp of practically the entire Terran R program. This came with a new design, plan, and even launch dates. These changes are meant to increase the rocket’s performance and decrease the cost and time it takes to launch it. Now in the middle of 2023, they have begun working on this next generation launch vehicle.

In the last few days, we received more information regarding what teams at Relativity have been developing, and work toward the first full Aeon R engine test. A milestone that has been a long time in the making. With Terran 1 now on the back burner, practically all of Relativity’s focus is on Terran R and getting this vehicle to orbit.

As a partially reusable heavy lift launch vehicle, it will not be easy but teams at Relativity are confident in the design and path of this rocket. Here I will go more in-depth into the recent progress, some of the changes made to Terran R, what to expect in the coming weeks, and more.

Aeon R Testing

After the first launch of Terran 1, we saw somewhat of a break from the company as significant developments and general updates slowed down. In regard to this, only a few days ago on the 1st Relativity CEO Tim Ellis tweeted saying, “Been pretty heads down and busy after launch – now working on our next phase of development and setting the stage for Terran R. Some solid development progress by the team, hardware continuing to ramp up, especially now with complete focus on a singular product to deliver on our $1.65B (and growing!) in contracts across 7 signed customers. I just walked by Aeon R engine chamber 009 today!”

When he says they have complete focus on a singular product, he’s referring to the fact that despite only ever being launched once, Terran 1 is not retired. It’s likely we will never see this launch vehicle lift off again. This is because the vehicle was meant to test the 3D printing process among other areas to see if the idea was viable. With the nearly successful first test flight, Relativity decided they could absolutely pursue this path but would rather do it with a larger and partially reusable rocket.

As mentioned in the tweet, Relativity’s signed customer backlog is around $1.65B in Launch Service Agreements (LSA’s) and additional several billion dollars in active customer LSA dialogue. This funding is crucial to the program and gives the company the resources necessary to continue.

Terran R’s first stage will be outfitted with 13 3D-printed gas generator cycle Aeon R LOx/Methane rocket engines each capable of 258,000 lb. sea level thrust, while its second stage houses a single LOx/Methane Aeon Vac engine with 279,000 lb. vacuum thrust. These engines benefit from Relativity’s advanced experience developing gas generator engines and vehicle stages with the oxygen/methane propellant combination. As far as progress, days ago when asked about Aeon R and whether or not the company was on track for a full engine static fire this year, Tim Ellis responded, “Yes, it’s tracking”

Since mid-2022, Relativity has been underway testing all Aeon R combustion devices at NASA Stennis Space Center – including the main Thrust Chamber Assembly (TCA), gas generator (GG), and gas-gas ignition system – at full scale and 100% power with high combustion efficiency. All engine active valves are developed in-house, with all valves produced, successfully actuated, and in development testing. In February 2023, the company completed its first full build of an Aeon R engine. Now we are not far away from the first full Static fire.

The engine composition on the first stage is comprised of four outer fixed engines aligned underneath four landing legs, and nine center gimbaled engines, providing enhanced reliability on vehicle ascent with engine-out capability. On both Terran R stages, the LOx propellant tanks are forward of the methane tanks, separated by a printed common dome. Subcooled cryogenic propellants are used on all parts of the vehicle except for the first stage liquid oxygen system, where subcooling is not necessary to meet performance goals.

It’s important to point out that Aeon R benefits from the heritage of its smaller predecessor, Aeon 1, which is used onboard Relativity’s Terran 1 rocket. Migrating many of the same thoughtful propulsion system architecture decisions from Aeon 1 to Aeon R has unlocked a high rate of iterative design and fast-tracked much of the Aeon R test program.

Big Changes

Initially, Relativity was advertising that the first launch of Terran R would be in 2024. Even with the previous design this was an extremely ambitious launch date and didn’t seem possible. This being said, with the announcement of the new rocket design and plan, they also released a new launch date of 2026. Based on the company’s current progress and the work that still needs to be completed, this is a realistic timeframe that they could very well achieve.

One of the biggest threats to this rocket’s future and the timeline in particular is the challenges of building such a complex rocket. Reusability alone for example is by no means easy to develop, test, and execute successfully. With this in mind, instead of Terran R being fully reusable as previously planned, the new design only features a reusable first stage. This will still present some challenges but it’s much more doable going from an expendable rocket to a partially reusable rather than all the way to fully reusable.

Specifically, Terran R will feature two near body-length aero strakes, four unique slider-mechanism landing legs, and four printed actuating grid fins. These features are meant to optimize first stage reusability, enabling rapidly scaled launch cadence for customers together with greater payload to orbit and lower costs versus other reusable architectures. In a statement, the company said, “Terran R’s innovative first stage architecture allows for a high angle of attack reentry which reduces propellant required for reentry burns, aerodynamic design for better reentry stability and improved control authority, and a passively actuated landing leg deployment system which is elegantly simple, lightweight, and highly operable for rapid reuse. An 18-foot vehicle diameter also aids vehicle stability with lower requirements on landing legs. Terran R will have an electromechanical actuator (EMA)-based engine thrust vector control (TVC) system, and also use EMA’s for grid fin control, in addition to in-house developed avionics and flight software. Additionally, the vehicle features a reentry heat shield on the aft end designed for rapid reusability” they said.

The company points out that from day one, Terran R was intentionally designed for reusability. The company intends to design major parts of the vehicle for 20 reuses right away, with strategic development of reusability criteria and rapid learning from flight data to continuously improve through successive vehicle block upgrades. Focusing on our customer’s needs for urgent, disruptive, relevant, and diversified launch supply in the medium-to-heavy payload market, they chose to prioritize optimizing for first stage reuse initially. Each early flight of Terran R will seek to deliver customer payloads to orbit reliably. Then, after vehicle ascent, Max-Q, MECO, stage separation, and second stage ignition – with the customer payload well on its way to orbit – the first stage will begin its entry, landing, and reuse journey.

Shortly after stage separation, the first stage of Terran R will perform a slow flip maneuver using its cold gas Reaction Control System (RCS). Grid fins deploy, followed by igniting engines to complete entry burns, slowing velocity and reducing peak loads and heating. Vehicle aero surfaces and strakes are designed to reduce the payload penalty for reuse with less propellent used on entry burns. Additionally, unique aerodynamic features result in a more stable entry profile with controlled flow separation around the vehicle. Terran R is designed for atmospheric entry with grid fin control. The vehicle will then ignite engines for a landing burn and command the leg slider mechanism to open, which will then passively deploy with the aid of aerodynamics. The first stage will then touchdown on a downrange ship in the ocean. Once the first stage has completed its reentry, it will go for inspection, refurbishment, and recertification for its next flight from Cape Canaveral.

Based on all this information, in the next few years, we can expect developments on an ocean landing platform and this overall system. All of which are necessary in order to reuse such a large first stage after payload deployment.

With satellite technology advancements, demand for bandwidth soaring, and satellite constellations representing the largest part of the growing launch market with a Total Addressable Market of over $30B/year by 2030, Terran R was developed to accommodate the growing demand for large constellation launch services. With a payload fairing that offers the right market fit to meet a variety of needs, Terran R supports use cases from dedicated payload deployments of constellation customers or single geosynchronous satellites to rideshare configurations for multiple customers per launch.

Conclusion

Relativity has very big plans for Terran R and its future. In the time since the first launch of Terran 1, the company has been focusing on the next generation launch vehicle and its engines in particular. We will have to wait and see how it progresses and the impact it has on the space industry.