Facility for Real-time Test and Verification of LEO Space Plasma Phenomena

We developed facilities for full-scale testing of small spacecraft in a low Earth orbit (LEO)–type environment. The vacuum and plasma equipment are capable of producing streaming ions (1–4 eV) using various gases while... [ view full abstract ]

We developed facilities for full-scale testing of small spacecraft in a low Earth orbit (LEO)–type environment. The vacuum and plasma equipment are capable of producing streaming ions (1–4 eV) using various gases while simultaneously producing low-energy electrons (~0.1 eV), thus simulating the mesothermal condition of the LEO plasma environment with high fidelity. Additionally, the vacuum facility is capable of thermal cycling and is equipped with plasma diagnostic tools. Various types of feedthroughs facilitate functionality such as (but not limited to) spacecraft charging experiments, high-voltage biasing of test articles, electron emission (thermionic cathodes of refractory metals, field emission, photoemission, etc.), Langmuir probes, Mach probes, RPAs, X-Y linear stages, hollow cathode plasma contactors, surface finish experiments, and quality assurance testing at full scale of small-scale spacecraft. The plasma environment can be varied in real time to simulate realistic orbital conditions such as space weather or transitioning into or out of eclipse.

Primarily, our facilities have been used to explore passive mitigation techniques of spacecraft charging, which causes significant error when performing in-situ Langmuir probe measurements. Full-scale testing of 3-U spacecraft–probe configurations reveal that charge neutralization is obtainable on small-scale spacecraft if a transparent conductive film is applied to the outer surface of solar panel coverglass and connected electrically to spacecraft ground.

Our developments of the LEO-like plasma source are planned to be extended at NASA MSFC to simulate irregular ionospheric conditions similar to those experienced during a space weather storm, functionally test MSFC’s CARLO instrument, and functionally test Penn State’s experimental pulsed Langmuir probe (PLP), with the intent of raising the TRL of both instruments.