Vacuum for Space Simulation and Research

Tests for ion engines like radio-frequency ion thrusters, Hall-effect thrusters, and other plasma-based propulsion systems require vacuum environments where background pressure and propellant partial pressure are kept low enough to avoid facility-induced alterations of exhaust expansion and beam characteristics.

Depending on thruster type and propellant flow, operating pressures typically range from the 10^-7 hPa (mbar) regime to several 10^-5 hPa (mbar).

Electric propulsion commonly uses noble propellant gases such as xenon or krypton, whose high molecular weight and flow rates impose significant demands on the vacuum system.

Pfeiffer provides scalable pump concepts – from compact turbomolecular vacuum pump units for laboratory setups to high-throughput systems for full-scale thruster testing. They are designed to maintain stable pressure under continuous noble-gas load. Integrated pressure measurement and residual gas analysis (RGA) allow continuous monitoring of gas composition and verification of the facility’s test envelope during operation.

Chemical propulsion tests, including those for rocket engines, generate very high gas loads and abrupt load transitions, especially during ignition. To maintain stable back pressure under these conditions, the vacuum system must deliver high pumping speed and respond rapidly to changing throughput.

Pfeiffer achieves this with its vacuum booster pump units that combine vacuum boosters with dry screw pumps. This design distributes the gas load across several stages, prevents thermal overload, and provides the required throughput in the rough and medium vacuum range.

Frequency-controlled operation enables the pumping speed to match the transient gas load. System performance can be verified with large-orifice step-load tests that reproduce the expected load profile before firing.

In explosive environments where flammable propellants or ignition sources must be considered, ATEX-compliant configurations are available.

In a thermal vacuum chamber (TVAC), vacuum conditions and defined temperature environments are created to simulate space.

Heat transfer occurs without convection, so temperature is controlled through external heating or cooling concepts such as thermal shrouds. This allows components to be tested for stability and performance under space-relevant pressure and temperature conditions.

Ion thrusters ionize a propellant gas such as xenon and accelerate the ions using electric or magnetic fields. The resulting ion beam produces a low but continuous thrust, enabling efficient long-duration propulsion for satellite positioning and deep-space missions.

Space propulsion is based on Newton’s third law:expelling mass in one direction generates movement in the opposite direction.

Chemical engines expel hot exhaust gases, while electric propulsion accelerates charged particles. Even without air, the expelled mass provides the reaction force that generates spacecraft motion.

Pressure requirements depend on the application. Many thermal vacuum and material tests operate in the medium vacuum range, while electric propulsion tests often require ultra-high vacuum (UHV) to prevent ion beam distortion and unwanted interactions between propellant particles and the facility.

Materials used in space vacuum testing must exhibit low outgassing, stable mechanical behavior under thermal cycling, and clean, vacuum-compatible surfaces.

Stainless steel is the standard material for vacuum chambers and internal components, as it has inherently low outgassing. Stainless steel surfaces of chambers and components are commonly glass-bead blasted, ground, milled or electropolished. Proper cleaning and leak-tight assembly are essential, and thermal bake-out is often applied to further reduce surface-related gas loads.

Elastomer seals represent the dominant source of residual gases. In addition, materials within the device under test, such as polymers, paints, adhesives, and electrical components, frequently dominate the overall outgassing behavior. These materials are therefore assessed using standardized screening parameters such as Total Mass Loss (TML) and Collected Volatile Condensable Materials (CVCM) as defined in NASA and ECSS material testing standards.

Vacuum bake out removes adsorbed water and volatile compounds by heating components under vacuum. This reduces contamination risk for optics, detectors, or propulsion hardware and helps achieve stable pressure in subsequent tests.

Bake out is a typical step in material screening and qualification processes.

Contaminants can migrate and condense on cold surfaces in vacuum, affecting optical coatings, detector performance, or thermal-control surfaces.

Clean surfaces, low-outgassing materials, and controlled vacuum conditions ensure test results accurately reflect behavior in space.

Ion-thruster testing typically requires vacuum levels from the 10^-7 hPa (mbar) range up to several 10^-5 hPa (mbar), depending on propellant flow and thruster type.

Vacuum systems must provide high pumping speed to remove xenon or krypton exhaust and maintain stable background pressure. Residual gas analysis can be used to monitor gas composition during thruster operation.

Every test requirement is unique. Pfeiffer designs and builds custom thermal vacuum chambers and integrated vacuum pump units tailored to specific mission profiles.

Whether the goal is ion-thruster plume analysis, material outgassing studies, or telescope mirror coating, our engineers provide end-to-end support – from system design and calculation to installation, calibration, and service.

Contact our experts

Pfeiffer combines more than 130 years of vacuum engineering experience with deep application knowledge in aerospace and research environments. From compact university test rigs to full-scale propulsion facilities, we deliver complete systems – vacuum chambers, pumps, gauges, and analysis tools – that ensure stable, contamination-free, and repeatable test conditions.

Our global service network and close collaboration with research institutes make Pfeiffer a trusted partner for reproducing the conditions of space on Earth.

Electric rockets are propulsion systems that use electrical power to ionize and accelerate propellant gases such as xenon. They produce low but continuous thrust and operate in high or ultra-high vacuum conditions

Chemical rockets generate thrust by burning propellants, producing hot exhaust gases and high mass flow. They require vacuum systems that can handle large gas loads and rapid transients during ignition.

Pfeiffer combines more than 130 years of vacuum engineering experience with deep application knowledge in aerospace and research environments. From compact university test rigs to full-scale propulsion facilities, we deliver complete systems – vacuum chambers, pumps, gauges, and analysis tools – that ensure stable, contamination-free, and repeatable test conditions.

Our global service network and close collaboration with research institutes make Pfeiffer a trusted partner for reproducing the conditions of space on Earth.