Taxi Testing for the New Radian One Prototype

On September 25, 2024, Radian Aerospace revealed the prototype PFV01, a 5-meter-long carbon fiber version of its spaceplane Radian One, declaring the successful execution of the first ground taxi tests. Powered by two jet engines, the vehicle underwent multiple pitch-up maneuvers and short hops to evaluate low-speed takeoff and landing characteristics.

NEWS: We’re excited to announce the completion of ground taxi tests for our first prototype flight vehicle, PFV01, marking an important milestone in the advancement of Radian One, the world’s first single-stage-to-orbit #spaceplane.

Learn more: https://t.co/4NP6ccduSN
— Radian Aerospace (@RadianSpace) September 25, 2024

Radian engineers will use the data collected by various telemetry systems to develop further flight control systems and determine if the analytical predictions are aligned with real-world behavior.

“These successful tests represent an early but significant step in our broader journey to bring Radian One to market. While we know there is much work ahead, each step in our robust test program brings us closer to transforming access to space with rapid, reusable, and cost-effective transport to low Earth orbit.”
— Richard Humphrey, co-founder and CEO of Radian

Taxi testing for a spaceplane

The Radian One takes off using its special rocket sled stage 0 and ignites its rocket engines to reach orbit as a Single-Stage-To-Orbit (SSTO), and it will subsequently land on a normal runway. As for every airplane, it needs to maneuver at low speed on the ground in the airport environment. Taxi testing is a common step for any new aircraft development. Radian One is no exception, due to its way of landing.

Radian Aerospace's (Radian) PFV01 prototype vehicle during the initial round of taxi tests. Credits: Radian Aerospace — *Radian Aerospace’s (Radian) PFV01 prototype vehicle during the initial round of taxi tests. Credits: Radian Aerospace*

PFV01 provided additional data about its aerodynamic performance and stability during the taxi testing short hops, including insightful indications about its center of gravity.

“This vehicle gives us the ability to adjust the center of gravity forward and aft, up and down, it gives us the ability to adjust the location of the landing gear.”
— Livingston Holder, Radian co-founder and CTO

More testing before flying

In the coming months, Radian will analyze the data collected so far, before continuing the ground testing on a longer runway in the same region. This will allow them to expand the flight envelope and test the vehicle performance at a higher speed. The company will use the same PFV01 or a modified version to evaluate different configurations.

As the company progresses with its prototype testing campaign, future test vehicles will face more challenges. These include aerodynamics for sled separation, integration of rocket engines, thermal protection, and control surface optimization. The first rail sled test will be conducted in 2025, along with the full-scale Radian One flight to space in 2028 and the orbital flight in 2029.

Radian One in Low Earth Orbit, an artist rendering. Credits: Radian Aerospace. — *Radian One in Low Earth Orbit, in an artist’s rendering. Credits: Radian Aerospace*

On the financial side, Radian raised $27.5 million in funding in early 2022 and is working on its next round. They have had productive conversations with potential customers about the vehicle’s ability to transport cargo to and from orbit, resulting in signing letters of interest.

^{*Cover image credit: Radian Aerospace}