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CONPROTEC'S MIXPAC® DISPENSING SYSTEM PLAYS IMPORTANT ROLE IN REPAIR APPLICATIONS FOR NASA SPACE MODULES
Marshall Space Flight Center (Huntsville, Alabama) is
developing a kit for the external repair of NASA space
modules that incorporates MIXPAC® hand held dispensers
as an essential part of the patching system. KERMIt, NASA's
"Kit for External Repair of Module Impacts," has been
created by Marshall researchers to seal punctures in the
International Space Station that are caused by collisions
with meteoroids or space debris. With this kit crewmembers
can seal punctures from outside damaged space modules
that have lost atmospheric pressure. ConProTec Inc.,
of Salem, New Hampshire, the world's leading developer
of 2-component adhesive dispensing systems, manufactures
these systems for NASA's kits.
"We're pleased to be providing an important element of these NASA kits. MIXPAC®
Systems represent an innovative technology for dispensing
adhesives in a wide variety of conditions. When used in
patching space modules the repairs can be done quickly
and safely, because the dual cartridge system allows adhesives
to be stored for months without cross contamination and
assures the adhesive's ratio is exact," states Richard
Wilson, ConProTec's Technical Director.
A kit for external patching was developed by NASA for several important reasons: it helps to speed repairs which are often limited by time constraints, it provides accessibility to damaged module areas; it is ideal for repairing collateral damage, and it is compatible with Extra Vehicular Activity (EVA) suits.
Punctures can cause module pressures to drop rapidly, resulting in reductions in the time available for a crew to diagnose the damage, move a repair kit to the problem, and patch the leak. Minimal internal accessibility to leak locations by the crew usually will require them to make external repairs; moreover, outside the module, more room is available for repair operations.
A repair kit such as KERMIt has three components: patches, tools, and adhesive. The MIXPAC® System 400 dispenser is the tool used to inject adhesives when making external patches for space module repair. MIXPAC® dispenser systems consist of a dispenser, a dual-barrel cartridge and a plastic static mixer that work as a completely integrated system.
Patching operations involve two basic crew EVA operations. First, the crew must locate and examine the hole and make preparations for the patching. Then, in a second EVA, the patch is applied by using an adhesive injector or dispensing system. With the adhesive stored in a dual cartridge, the patching operation is simplified and the proper mixing is insured. Also, with dual cartridges, the catalyst and resin are stored separately, thereby preventing cross contamination.
"Space station crew members faced with making external repairs under time constraints have a dispenser that is ready to be used. They do not need to take the time to mix adhesive components in what is essentially an emergency situation," adds Wilson.
A key feature of the MIXPAC® system contributes to the success of repairs. Dual-cartridge containers are vacuum filled to ensure that no air becomes trapped in the cartridge, and that the adhesive is properly metered. ConProTec works closely with NASA to modify the dispenser systems for use outside of a space station or module. An insulating blanket was added to the dispensing system so that it operates effectively in the cold temperatures outside the International Space Station. In addition, since crew members will be wearing heavy gloves while outside a module making repairs, NASA and ConProTec altered the handle design to simplify manipulation of the dispensing system.
The Marshall Center has been developing and testing the KERMIt Patch Kit since 1998, testing for leakage, adhesive flow, crew interface adequacy, etc. They expect to deliver an operational patch kit late in 2000, incorporating the MIXPAC® dispensing system as an integral part of the kit.
Overall, MIXPAC® dispensing systems are proving to be beneficial to NASA, as well as many other manufacturers utilizing adhesive dispensing systems. For example, Thiokol Propulsion, a division of Cordant Technologies, Inc., and manufacturer of NASA's Space Shuttle reusable solid rocket motors (SRSMs), uses a MIXPAC® system to dispense epoxy adhesives in the nozzle bond process. Operators insert the dual-cartridge system into the adhesive dispensing gun, attach a MIXPAC® static mixer, and then easily dispense the exact amount of adhesive necessary.
In other applications, manufacturers are realizing higher productivity and cost savings by selecting the easy-to-use and environmentally safe, hand-held MIXPAC® adhesive dispensing systems. Using these systems reduces the amount of hazardous and material waste that is generated and enhances employee productivity by reducing preparation times. Ratio control is achieved, since the integrated system of dispenser, dual cartridge, and static mixer ensures that the correct amount of adhesive is dispensed from both sides of the cartridge. Finally, by using a system in which the adhesives are contained in cartridges, employees are not exposed to hazardous material.
Whether they are helping NASA repair space modules quickly
and safely, or making adhesive dispensing efficient and
effective for a wide range of vendors, MIXPAC® Systems
are increasingly playing an essential and innovative role
in a wide array of mission-critical adhesives solutions.
Jeannie Bellizzi
Gray & Rice Public Relations
617-367-0100 x100
jbellizzi@gr2000.com
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