NASA SBIR Phase I: Large-Area, Atmospheric Pressure Plasma Jet for Spacecraft Surface Sterilization for Planetary Protection

APPJ being used to treat an 0.1 ml drop of stock Bacillus atrophaeus endospore solution placed onto an individual piece of aluminum tape adhered to the bottom of a Petri dish.

The planetary science community is interested in exploring solar system bodies with the potential for life detection, which requires technologies that implement Contamination Control for Planetary Protection. Currently, the only approved full-system microbial reduction method is dry heat microbial reduction, which requires heating of the spacecraft to high temperature for a fixed length of time at a specific humidity. While this technique is practical and effective, some state-of-the-art electronics and other thermally sensitive components make this technique unusable for certain materials.

One potential alternative technique for surface sterilization of a fully assembled spacecraft or components is the use of atmospheric pressure plasma jet (APPJ), which has been an area of investigation within the biomedical community. The APPJ has the advantage that the plasma is ejected from a device (up to several centimeters) and travels to the surface to be sterilized. Eagle Harbor Technologies (EHT), Inc. is proposing to develop a large-area APPJ for spacecraft surface sterilization. EHT will leverage the previously developed EHT nanosecond pulser, which provides unprecedented control of output voltage, pulse width, and pulse repetition frequency. This capability will allow EHT researchers to develop and optimize an APPJ for surface sterilization.

The primary goal of the proposed SBIR program is the development of a large-area atmospheric pressure plasma jet (APPJ) for spacecraft surface sterilization for Planetary Protection. The Vision and Voyages for Planetary Science in the Decade 2013-2022 outlines potential planetary missions that require the need for developing advanced Contamination Control for Planetary Protection technology over the next decade, especially for Mars, Europa, and Enceladus missions. The EHT large-area APPJ would complement other contamination control technologies in NASA’s toolkit. The EHT large-area APPJ would allow for the sterilization of materials that cannot be subjected to other sterilization technique and thereby allowing spacecraft designers to utilize a wider range of components and materials.

Surface sterilization is an important issue for the medical community. In hospitals the ability to sterilize a surface without chemicals or heat would potentially allow for faster, more robust cleaning of surfaces. The large-area nature of the EHT APPJ would allow large surfaces to be sterilized more quickly. Additionally, surface sterilization with large-area APPJ could play an important role in biomedical research laboratories to prevent contamination of instruments and surfaces while limiting the spread of infectious diseases. Another commercial application of the EHT large-area APPJ is surface treatments. APPJs are used for the treatment, cleaning, and modification of surfaces for a wide range of applications from nanoparticle production to improving material bonding.