A technology that has shielded some of NASA's highest-profile space observatories from potentially harmful molecular contamination is now being evaluated as a possible solution for protecting the Smithsonian Institution's cultural artifacts and natural-science specimens.
Under a Space Act Agreement with the Smithsonian Institution's National Museum of Natural History, Nithin Abraham, a thermal-coatings engineer at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and museum conservators are testing the effectiveness of the patent-pending Molecular Adsorber Coating, or MAC. Goddard engineers originally created the technology to entrap outgassed molecular contaminants so that they couldn't adhere to sensitive instruments and components.
Made of zeolite, a mineral widely used in water purification, and a colloidal silica that acts as a glue, MAC is highly permeable and porous -- attributes that allow it to trap contaminants that outgas in a process similar to what creates the new car smell in vehicles. Because it doesn't contain volatile organics, the coating itself doesn't cause additional outgassing. Easy to use, the coating can be applied directly to the hardware itself or on varying-sized panels that are inserted inside instrument cavities and test chambers.
Target Contamination: Mercury Vapour
Under the one-year research effort begun last summer, Goddard and museum personnel are determining whether MAC can reduce the presence of mercury vapour and other contaminants that offgas from plant and mineral specimens. These contaminants are tainting specially designed metal cabinets at the Museum Support Center in Suitland, Maryland, a sprawling storage facility that holds more than 54-million collection items.
These offgassed chemicals pose health risks to humans and degradation to specimens, said Collections Program Conservator Catharine Hawks, who has used a wide range of techniques and materials to take up and hold vaporized contaminants in both exhibit and stored specimens. "Conservators are constantly faced with problems of volatile contaminants -- either cross-contamination among collection materials or contaminants that come from materials used with collections," she said. "Consequently, we're always in need of technologies to provide protection."
Learning of the Goddard-developed coating, Hawks said she and other museum conservators thought it worthwhile to explore MAC's effectiveness in artifact protection. Abraham agreed. "We thought this collaboration presented us with an interesting opportunity to explore how MAC would perform in terrestrial environments," she said. "We have quite extensively tested the coating to mitigate outgassing in vacuum environments for space applications, but not in ambient conditions."
The team plans to write a technical paper about the coating's effectiveness once testing is complete. "We have gained valuable knowledge on better ways to test the coating and advance the technology for distinct applications", Abraham said.