Assembly in Action: Dispensing System Plays Role in Space Modules
KERMIt 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 a module's pressure to drop rapidly, giving the crew little time to diagnose the damage, get a repair kit to the problem and patch the leak. Minimal internal accessibility to leak locations usually re-quires the crew to make external repairs. Moreover, outside the mod-ule, more room is available for repair operations.
The 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 modules. MIXPAC dispensing systems consist of a dispenser, dual-barrel cartridge and a plastic static mixer.
Patching operations involve two basic crew operations. First, the crew must locate and examine the hole and make preparations for the patching. Then, 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 ensured. Also, with dual cartridges, the catalyst and resin are stored separately, preventing cross contamination.
A key feature of the MIXPAC system contributes to the success of the repairs. Dual-cartridge containers are vacuum-filled to ensure that no air becomes trapped in the cartridge and that the adhesive is correctly metered. To use the dispenser system outside of a space station or module, an insulating blanket was added to the dispensing system so that it operates efficiently in the cold temperatures outside the International Space Station. Additionally, because crew members will be wearing heavy gloves while making external repairs, the dispenser's handle design was altered to simplify manipulation.
For more information on dispensing systems, call ConProTec Inc. at 603-893-2727, visit www.conprotec.com or Reply 2.