Exploration Helmet Permanent Anti-Fog Study

For the current Extravehicular Mobility Unit (EMU) spacesuit, an astronaut applies an antifog solution to the interior of the helmet bubble before each EVA. However, the anti-fog
solution has been reported to cause eye discomfort during at least seven EMU EVAs when the
anti-fog solution contacted the crew member’s eyes. During STS-100, astronaut Chris
Hadfield reported the eye irritation temporarily blinded him during his spacewalk. In
addition, the wipe on anti-fog solution is a consumable that needs to be accounted for and a
supply launched for missions. To solve this, NASA has tested different permanent anti-fog
coatings. However, major issues have arisen with Human in the Loop (HITL) testing with the
coatings. Cleaning and removing Valsalva devices which use pressure sensitive adhesives have
been challenges to avoid damaging the permanent anti-fog coating. Due to these issues, further
investigation is being completed evaluating two solvent based anti-fog solutions: Exxene’s
HCF-100 and FSI’s Visgard 106-94. Each coating will be evaluated on polycarbonate samples
for application consistency, steam cycles (mimicking breath cycles), cleaning durability, haze,
and light transmission. This study will determine if either coating is a viable option to pursue
as a permanent anti-fog for spacesuit helmet applications.