The "DRAG-ON" facility (Dual-chamber for RArefied Gases and ON-ground testing) is used to simulate the high speed, low density flow that a spacecraft would encounter in (Very) Low Earth Orbit, (V)LEO, at an altitude of approximately 200 km - intermediate between the "Kármán line" (100 km) and the orbit of the International Space Station (400 km).
The facility supports the investigation of a new concept of electric propulsion called Air-Breathing Electric Propulsion. This new technology would make it possible to use the atmosphere as a propellant.
Another application includes the exposure of satellite material samples to the atomic oxygen beam. Some materials may suffer from oxygen erosion and may cause critical damage to the satellite. Different material samples or representative satellite geometries can be tested in DRAG-ON to evaluate their effectiveness for VLEO space applications. The orbital flow conditions are created through a Particle Flow Generator (PFG) that can operate continuously in vacuum conditions with both argon and molecular oxygen feed gases. The working gas is ionized from an inductively coupled plasma source. The charged particles are then accelerated to orbital speed (8 km/s) using an electric field. A sealed chamber and a high vacuum pumping system are necessary to maintain the pressure around 0.001 Pa (1/100th of a millionths of an atmosphere) during operation. Plasma diagnostics include electrostatic probes (Faraday probe to measure plasma current density and Retarding Potential Analyzer to measure velocity distributions) and non-invasive techniques (Optical Spectroscopy).
Vacuum environment
- Roughing pumps
- Turbomolecular pumps
- Pumping speed (N2): 3050 l/s + 2150 l/s
- Ultimate pressure < 1 x 10-7 mbar
- Operating pressure < 8 x 10-5 mbar
LTA-100 plasma source
- Output beam current 10 mA
- Ion energy 5 - 50 eV
- Exit beam diameter 90 mm
- Operating gas: Ar, O2
