Sierra Space Successfully Concludes Testing of VR35K-A Upper Stage Engine

Written by Copernical Team Sunday, 16 February 2025 05:25

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Los Angeles CA (SPX) Feb 16, 2025

Sierra Space, a pioneering force in commercial space and defense technology, has completed the test campaign for its fully integrated VR35K-A upper stage engine. Conducted at the Air Force Research Laboratory's (AFRL) Rocket Propulsion Division at Edwards Air Force Base in California, this milestone underscores the company's progress in developing next-generation propulsion systems. The co

Sierra Space Successfully Concludes Testing of VR35K-A Upper Stage Engine
by Clarence Oxford
Los Angeles CA (SPX) Feb 16, 2025

Sierra Space, a pioneering force in commercial space and defense technology, has completed the test campaign for its fully integrated VR35K-A upper stage engine. Conducted at the Air Force Research Laboratory's (AFRL) Rocket Propulsion Division at Edwards Air Force Base in California, this milestone underscores the company's progress in developing next-generation propulsion systems.

The company has also secured a $16 million firm-fixed-price contract from AFRL to further advance its upper stage engine technology for National Security Space Launch (NSSL) missions. This follows a previous $22 million contract awarded in July 2023 by the Air Force Test Center at Edwards Air Force Base.

The VR35K-A is a high-performance liquid oxygen (LOX)/liquid hydrogen (LH2) engine featuring a fuel-rich staged combustion cycle, a cutting-edge turbopump architecture, and a VORTEX combustion chamber. Generating 35,000 pounds of thrust, the engine achieves superior performance compared to existing market alternatives. Sierra Space's patented VORTEX technology ensures stable and efficient combustion, with active cooling mechanisms enhancing both performance and reliability.

"Our powerful new upper stage engine, the VR35K-A, represents a groundbreaking advancement in propulsion technology, leveraging Sierra Space's patented VORTEX engine design to achieve unprecedented efficiency, reliability and affordability," said Dan Polis, Vice President of Engineering Solutions and Propulsion Systems at Sierra Space. "We are delivering high performance, reduced complexity and significant cost savings with this revolutionary new product, allowing our customers and partners to deliver up to 30% more payload mass to orbit. This engine is a testament to our company's commitment to pushing the boundaries of space commercialization with cutting-edge, scalable solutions."

Key features of the VR35K-A include:

+ Streamlined Functionality: A single-shaft turbopump assembly simplifies startup and shutdown processes.

+ Precise Fuel Regulation: Mechanically-coupled mixture ratio control ensures optimal fuel and oxidizer balance.

+ Advanced Manufacturing: Additive manufacturing techniques lower production costs and reduce lead times for intricate components.

The engine underwent rigorous testing throughout 2024 at Sierra Space's Badger Propulsion Test Facility in North Freedom, Wisconsin. The campaign successfully met all performance objectives, including stable thrust chamber operation, turbomachinery efficiency, precise mixture ratio control, throttle capability demonstrations, and high overall engine efficiency.

Sierra Space collaborated with Florida Turbine Technologies, a subsidiary of Kratos Defense and Security Solutions, Inc., to develop and test the turbomachinery integrated into the VR35K-A. The single-shaft main turbopump assembly enhances reliability and streamlines operation. Before full engine integration, Sierra Space validated performance through an extensive turbomachinery test campaign.

"Kratos is a leader in propulsion technology, dedicated to the rapid development, demonstration and deployment of innovative solutions," said Stacey Rock, President of Kratos' Turbine Technologies Division. "Our philosophy is to collaborate with industry leaders who share our mission of delivering cutting-edge technologies and capabilities to market quickly and cost-effectively. This partnership with Sierra Space has been highly successful and represents a cornerstone of our long-term strategic initiatives."

The VR35K-A engine is designed to support increased payload delivery to Low Earth Orbit and beyond. Sierra Space is also leveraging its VORTEX combustion chamber technology for in-space propulsion applications, including orbital maneuvering and extraterrestrial landing systems. Notably, the company's Dream Chaser spacecraft employs VORTEX-powered thrusters for its reaction control system.

Following the successful completion of component testing in 2023, Sierra Space advanced to full engine hot fire trials. The company now moves into an extensive qualification phase as it continues to mature its upper stage engine technology.