ILC Dover Research Articles

Efficacy Testing of Personal Protective Filters on Biosafety Level 4 Positive Pressure Suits.

Introduction: Positive pressure breathing air-fed protective suits from three vendors are commonly used in biosafety level 4 (BSL-4) laboratories: they are Dover Chemturion suits (ILC Dover, DE), Delta suits (Honeywell Safety, NC), and HVO suits (HVO-ISSI-Deutschland GmbH, Germany). To address the potential risk of infectious agents being introduced through the supplied breathing air stream, some suit manufacturers incorporate protective filters on the suits themselves. However, these integrated filters are not amenable to in situ testing for efficacy verification. We have been using external filters from Matheson USA on the positive pressure suits since our BSL-4 laboratories were commissioned two decades ago. As part of our BSL-4 protective suit management program, we test these filters before them being put into use, and annually thereafter. In the past few years, we have observed these filters failing at a higher rate, as high as two out of three of the new filters tested at one point. Objective: The purpose of this study was to procure personal protective filters from other sources and validate their efficacy long-term. Methods: Filters from Respirex, HVO, and Honeywell were validated for filter integrity and filter loading. Results: Respirex filters performed well during the initial testing and periodic testing thereafter. Regular testing of the Respirex filters has now been ongoing for 30 months with continued successful performance. Conclusion: Filters from Respirex are a suitable option to protect personnel wearing positive pressure suits in BSL-4 laboratories.

Suiting up for the red planet

We're likely still at least a couple of decades away from landing people on Mars, but the space suits that will protect those astronauts are very much in development. Last year, NASA made headlines when it invited the public to choose the design that would decorate the exterior of the Z-2, a new suit designed to be mobile enough to explore the Red Planet. And its manufacturer, longtime space-suit maker ILC Dover, based in Frederica, Del., has now put the finishing touches on that suit, which is set for a public unveiling in a few months. Some would argue that we can't get started on Mars suits soon enough. Today’s space suits are designed for delicate work in zero gravity, not the rigors of a months-long trek around the base of Olympus Mons.

Showering BSL-4 Suits to Remove Biological Contamination

Positive pressure suits are widely used at BSL-4 to protect operators from contact with microbiological agents. As there is the potential for the outside of the suits to become contaminated during use, they must be decontaminated prior to final exit from the high-containment laboratory. Chemical showers are used to remove biological material from suits, and the shower effluent is collected for subsequent treatment by heat or chemicals. The efficacy of showering to clean/remove biological materials from two different BSL-4 suits (ILC Dover and Delta) was studied using Bacillus atrophaeus spores dried directly onto the suit surface as a surrogate contaminant, with a 4 log colony forming unit (cfu) reduction pass criterion required. Initial studies using water alone, without disinfectant, achieved a 1–2 log cfu reduction in the microbial contamination. However, direct scrubbing, using a lightweight brush combined with relatively short cycle times (6 minutes) and low water volumes (<45 L per cycle) achieved an average spore reduction of 3.4 log cfu from the suit. The log cfu reduction was dependent on suit type, position of the contamination on the suit surface, and suit fit. Higher reductions (mean 4.2 log cfu) were achieved with the ILC Dover suit than the Delta suit (mean 3.6 log cfu) when the tests were undertaken using experienced staff who had been matched to the suit size. The study highlights that assumptions cannot be made about the efficacy of shower decontamination systems for BSL-4 facilities and that familiarization with decontamination improves the efficacy of removal of biological material during showering.

Development and evaluation of the mars pathfinder inflatable airbag landing system

The entry, descent, and landing system of the Mars Pathfinder spacecraft includes a unique subsystem of airbags for impact attenuation. The airbag geometric configuration and associated landing dynamic analysis was performed by the Jet Propulsion Laboratory and Sandia National Laboratories (Mars pathfinder airbag impact attenuation system, paper AIAA-95-1552; Mars pathfinder impact, paper AIAA-95-1553). ILC Dover performed detailed design and fabrication of subscale and full-scale prototypes and flight airbag systems. This paper presents key steps in the development effort that produced the airbag system, including materials selection, patterning, fabrication issues, component design, and packaging/deployment. These steps outline many elements common to the development of engineered softgoods products for aerospace applications.

Manufacturing and Performance Assessments of Several Applications of Electrotextiles and Large-Area Flexible Circuits

ABSTRACTNumerous applications of electrotextiles and flexible circuits have been identified that can advance systems performance for many commercial, military, and aerospace devices. Several novel uses of electrotextiles have been developed for lab testing, while others have been utilized in products on the commercial market, as well as items that have flown in space. ILC Dover, Inc. has utilized conductive fibers in various inflatable and tensile structures for signal transmission and electrostatic charge protection. Conductive and pressure sensitive textiles have been incorporated in the advanced development space suit (I-Suit) as switch controls for lights and rovers, and as signal transmission cables. Conductive fibers have been used in several stitched applications for electrostatic charge dissipation. These applications include large pharmaceutical containment enclosures where fine potent powders are being captured for transfer between manufacturing facilities, as well as impact attenuation airbags used in landing spacecraft on the surface of Mars. In both cases, conductive threads are uniquely located in seams and panel locations to gather and direct charge through surface fibers and panel interconnects. Conductive fibers have also been utilized in a conformal Sensate Liner garment for the identification of wound locations and medical sensor signal transmission for soldier health monitoring while on the battlefield. The performance challenges of these structures require a careful, systematic application of electrotextiles because of the flexing, straining, and exposure of the materials to harsh environments. ILC has also been developing “gossamer” spacecraft components utilizing unique materials and multi-functional structures to achieve extremely low mass and low launch volumes. Examples of large deployable structures featuring very thin, large flexible circuits for use in space include synthetic aperture radar (SAR) antennas, communications antenna reflectarrays, and active variable reflectance solar sails. Design and materials challenges of electrotextile and large-area flexible circuit membrane structures as demonstrated in engineered applications will be discussed in this paper.

Inflatable composite habitat structures for lunar and mars exploration

Recent advances in materials technology have improved the performance capabilities of inflatable, flexible composite structures, which have increased their potential for use in numerous space applications. Space suits, which are comprised of flexible composite components, are a good example of the successful use of inflatable composite structures in space. Space suits employ inflatables technology to provide a stand alone spacecraft for astronauts during extra-vehicular activity. A natural extension of this application of inflatables technology is in orbital or planetary habitat structures. NASA Johnson Space Center (JSC) is currently investigating flexible composite structures deployed via inflation for use as habitats, transfer vehicles and depots for continued exploration of the Moon and Mars. Inflatable composite structures are being investigated because they offer significant benefits over conventional structures for aerospace applications. Inflatable structures are flexible and can be packaged in smaller and more complex shaped volumes, which result in the selection of smaller launch vehicles which dramatically reduce launch costs. Inflatable composite structures are typically manufactured from materials that have higher strength to weight ratios than conventional systems and are therefore lower in mass. Mass reductions are further realized because of the tailorability of inflatable composite structures, which allow the strength of the system to be concentrated where needed. Flexible composite structures also tend to be more damage tolerant due to their “forgiveness” as compared to rigid mechanical systems. In addition, inflatables have consistently proven to be lower in both development and manufacturing costs. Several inflatable habitat development programs are discussed with their increasing maturation toward use on a flight mission. Selected development programs being discussed include several NASA Langley Research Center habitat programs that were conducted in the 1960s, the Lawrence Livermore National Laboratory inflatable space station study, the NASA JSC deployable inflatable Lunar habitat study, and the inflatable Mars TransHab study and test program currently ongoing at NASA JSC. Relevant technology developments made by ILC Dover are also presented.