Measuring Thrust in Space Missions
In space, any spacecraft needs a propulsion system to perform maneuvers. Even small thrusters can make a huge difference by delivering orbit correction, station keeping, and trajectory control. Thus, thrust measurement is a crucial step in developing a propulsion system.
It is especially important for small satellite propulsion systems because their thrust can be as low as a few micronewtons. These values require specialized, highly sensitive measurement methods.
Before the thruster is cleared for the space mission, it is rigorously tested in the laboratory to ensure its readiness. Spacecraft propulsion testing allows for verifying that the system operates stably and that the actual micro-thruster performance matches the calculations.
Test Environment for Space Propulsion Systems
The conditions for propulsion system tests must be as close as possible to those in space. Additionally, the process involves verifying performance in all operational modes and under all relevant settings for in-orbit operation aboard the satellite. A vacuum chamber is used to achieve these goals.
During the vacuum chamber testing, the air is removed from the chamber. It allows for creating the environment in which the thruster will operate in orbit. This is important because many types of electric propulsion systems are sensitive to ambient pressure.
Protecting the measuring equipment from external influences is equally important. Vibration isolation systems are used for this purpose to minimize the effect of building and equipment vibrations.
Moreover, various sensor systems are used in the laboratory to acquire high-precision data and ensure stable and repeatable results within the propulsion test environment.
How Thrust Measurements Are Calibrated
Engineers have to perform a thorough thrust calibration of the measuring system before beginning the testing procedures. It is done to correctly register even the smallest forces.
There are a few stages in the calibration process. First of all, reference forces are applied to record the system response and to calculate the coefficients required to convert the measured displacement into a force value.
The next step is to check the data acquisition system. The engineers make sure that all the data from sensors is recorded correctly without any distortions.
Uncertainty analysis is another crucial step. Any measurement contains minor errors, and the engineers have to estimate them. This analysis allows for determining propulsion measurement accuracy and guarantees that the test results meet the requirements of the mission.
These procedures are a standard part of thrust stand calibration and are mandatory for the certification of propulsion systems.
Thrust Measurement for Artemis II Propulsion Testing
When the thruster is prepared for space missions, there is a series of laboratory tests. The propulsion system testing campaign includes checking the thruster performance, thrust measurement, and ensuring its stability.
As part of preparations for the Artemis II mission, these procedures ensured that propulsion systems met mission requirements. The tests were conducted in vacuum conditions, where specialists verified thrust performance and analyzed engine behavior under different operating modes.
Thrust measurement is a standard procedure. Basic and necessary stage in developing any propulsion system. This cycle of tests is conducted both during the research and development (R&D) stage and during acceptance testing of the finished product.
The main goal is to ensure that the propulsion system generates the required thrust consistently and repeatedly. Engineers have to check that the system works and obtain accurate quantitative data on its behavior.
During thrust measurement procedures, the level of thrust is determined. In addition, the operating mode of valves and other elements that control the supply of propellant is evaluated. It is also important to check that the entire control chain—from command to actual thrust—is working correctly and predictably.
As a result of testing, engineers obtained specific numerical data. These indicators show that the system is performing as expected, its characteristics are stable, and the thruster is ready for further testing and operation.
This approach is an important part of spacecraft propulsion validation and is used in the preparation for complex space missions.
About SteamJet Space Systems
SteamJet Space Systems is a leading UK-based provider of high-performance satellite propulsion solutions. We specialise in water-based thrusters designed specifically for CubeSats and Small Satellites (SmallSats), with a strong focus on water-based thruster safety.
By pioneering the use of green propellants and intelligent thermal engineering, SteamJet enables complex LEO (Low Earth Orbit) manoeuvres — including orbital maintenance, collision avoidance, and de-orbiting — without the risks associated with toxic hydrazine or high-pressure cold gas systems, advancing green propulsion for space missions.
Steamjet Propulsion Technology
Our modular systems are engineered for seamless integration and maximum safety compliance:
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