Technical specifications
The NSPTF provides the capability for hot firing chemical space propulsion rocket engines under vacuum conditions.
The open-access test facility for rocket engines operates in the range of 100N to 1,500N.
There is an instrumented thrust stand with full data acquisition. This includes two thermal imaging cameras and an optical camera looking at the engine in the test, giving a full 360° view of the engine, alongside flow and temperature measurements. There is also CCTV systems looking at the whole site as well as in the individual propellant and firing bays.
The facility currently utilises the Nammo J3 Test Cell, which is a horizontal firing facility. A dedicated and experienced testing team ensures all the operational aspects are taken care of. Propellant management, conditioning and analysis is available on-site, providing complete peace of mind.
The NSPTF can be used for development, qualification & acceptance testing of chemical thrusters. The test environment can be adapted to suit the test requirements needed. There is Monopropellant and bipropellant capability. The following types of rocket engines can be tested:
- In space propulsion rocket engines
- Launch vehicle apogee rocket engines
- Reaction control system thrusters
- Attitude control system thrusters
Propellant compatibility
The NSPTF currently operates using Nammo’s J3 test facility, a horizontal-firing hypergolic test stand.
Supported propellants:
- Hydrazine
- Monomethylhydrazine (MMH)
- MON-3
The NSPTF is designed for compatibility with High Test Peroxide (HTP). In 2022, a HTP engine was successfully tested at the NSPTF using a temporarily attached feed system. Whilst there is experience in house for testing HTP engines, a dedicated feed system is not currently available.
1st HTP campaign:
- April 2022
- 5 hot firing test days
- 119 firings
2nd HTP campaign:
- Nov 2025
- 2 hot firing test days
- 7 batches of firings (with each batch having multiple firings stitched together)
The Test Cell Control Room
The NSPTF has its own bespoke software and this provides full control over the site. The system is designed to operate by itself. Once operational, the system monitors all of its own conditions and is constantly feeding back data to let the test team know that it is optimally running. The autonomy of the control system allows the firing team to focus on the engine under test, and the number of personnel required to run the facility is minimised.
The test engineers are focused on making sure the engine works and that all the data being gathered is of the best quality that the end customer needs. Data is collected through the data acquisition system and real time engine monitoring software.
The interface is designed to attract the attention of the firing team if parameters move out of predefined limits. Error messages draw the attention of the firing team when required.
Once a hot-fire test is complete, the test team are able to collate all of the hot fire test data and pass it securely to the customer.
Managing the Hot Firing Exhaust
The exhaust from the rocket engine comes out at six times the speed of sound. The first step is to slow those gases down, which is achieved with a seven metre long supersonic diffuser.
In the process of slowing the gases down, we recover a lot of energy in the form of heat, which needs to be dissipated very quickly, which is achieved through the use of a very advanced heat exchanger. The exhaust gases are cooled from over 2000 degrees to less than 50 degrees in just a metre.
After which, the exhaust gases then travel along a vacuum manifold and are bought into the Vacuum pump plant and evacuated back into atmosphere.
Vacuum Environment
The NSPTF is capable of simulating near space conditions, with vacuum levels down to 1.5mbar, an approximate altitude of 168,000 feet (51.2 km). This is achieved through a set of mechanical electric pumps.
During hot firing, 60,000m^3 of gas is pumped through every hour.
The mechanical pumps provide fast start-up capability, with vacuum test conditions ready in <15 minutes. Similarly, fast return to atmospheric conditions is possible, minimizing rig down time.
The Electric pump set has been installed in a modular arrangement, with allowance for potential future expansion of the facility.
There is a high pumping capacity:
- 4.5mbar cell pressure (~120,000 ft) for 1.5 kN thrusters
- 1.5mbar cell pressure (~168,000 ft) for 1 kN thrusters
Speak to the team
Email the NSPTF team about our facility specifications and on-site support during your propulsion testing programme. We’d be happy to talk.