The people involved in the test preparations of ArianeGroup and the Justus Liebig University are standing in front of the vacuum test facility Jumbo
In February 2024, the Jumbo vacuum test facility at Justus Liebig University Giessen, Germany, hosted the GIESEPP MP measurement campaign. The goal was to demonstrate the capability of ArianeGroup’s RIT 2X at the operating points defined by the GIESEPP MP project. The successful completion of this campaign followed a series of preparatory tasks and the actual test procedure.
The Jumbo vacuum test system has long been a popular test facility for industrial partners in the electrical propulsion working group headed by Professor Klar in Giessen. In addition to its comparatively large volume of around 30 m2 with a length of 6 metres, it is also equipped with a powerful pump system. In full operation, the eight cryogenic pumps can achieve a pumping speed of 150,000 l/s for xenon at a base pressure of less than 2e-7 mbar after a pumping time of 24 hours. Jumbo is equipped with a water-cooled graphite beam dump for testing electric propulsion devices, which has been used successfully for beam powers of more than 4 kW. The large repertoire of diagnostics is also particularly attractive for industrial partners. In addition to a Faraday array for beam profile measurement, a 2D traversing unit is also available, which enables spatially resolved measurement of a wide range of diagnostics. These diagnostics include an ExB probe, Faraday cups, RPAs and a neutral gas probe. An optical access enables the use of non-invasive diagnostics such as optical emission spectroscopy or hot grid measurement.
Despite this infrastructure and the experience with many different thrusters, certain modifications to the configuration of the test facility were necessary for the test with AriangeGroup’s RIT 2X. Firstly, a new Test Power Supply (TPS) was put into operation, whose power supply units are designed for the operation of a high-performance thruster. Secondly, a new flowboard was installed. The flowboard was used to supply the thruster and the neutraliser with xenon. The main focus here was on precise gas volume control in order to be able to accurately record the propellant consumption of the thruster and neutraliser. This is an important parameter that is required in order to be able to assess the range of applications of the RIT 2X.
Preparations for the test were carried out together with ArianeGroup employees. A check of the power supply unit and measuring equipment used guaranteed reliable data acquisition during the test. The propellant supply lines were checked for leaks and the thruster control software from Justus Liebig University was adapted to the requirements of the RIT 2X. After the actual installation of the thruster, the diagnostics were aligned with the RIT 2X and all transport covers of the thruster were removed. After the vacuum system was closed and pump-down began, final checks were carried out on the software and measuring equipment. The end of the preparations and the start of the actual test campaign was marked by the test readiness review under the lead of ArianeGroup. Recording the preparations made and documenting the measuring equipment used ensures that the measurement data obtained during the test campaign is reproducible and reliable.
The smooth running of the test preparations is the result of the professional and close collaboration between ArianeGroup and Justus Liebig University.
