The Advanced Exploration Systems (AES) Logistics Reduction (LR) project Multipurpose Cargo Transfer Bag (MCTB) project focuses on repurposing cargo transfer bags for on-orbit outfitting. The MCTB task converts cargo transfer bags into useful crew items or life-support augmentation on-orbit after they have provided their primary logistics function. Reuse of the MCTB logistics carriers prevents the need to fly additional items. By repurposing MCTBs, dedicated crew items do not have to be launched and the overall launch mass is decreased. For non-LEO missions, the vehicle interior habitat volume will be relatively fixed. MCTBs will enable this volume to be used more effectively through reuse and rearrangement of logistical components. MCTBs reduce habitation trash generation rates.
The MCTB team worked with the ISS Vehicle Office and JSC Acoustics Office to determine the optimal material layup of an acoustic MCTB to absorb the sound of the ISS treadmill. Located in Node 3 on ISS, the treadmill reaches the noise hazard limit of 85 dBA when operated at high speeds. As such, the treadmill has been added to the Noise Hazard Inventory, and hearing protection has become mandatory when the treadmill is used above 10 mph per the Noise Constraint Flight Rule. An acoustic MCTB was designed with a material layup specifically designed to absorb the sound generated by the treadmill. Four Acoustic MCTBs were designed, fabricated, and delivered in the first half of 2015 and launched to ISS on Orbital's fourth cargo resupply mission (Orb-4) in December 2015. After serving their primary purpose of carrying logistics, the MCTBs was reconfigured to flat panels and attached in a dual layer to two walls in proximity to the treadmill. They reduced the treadmill noise by 2-3 dBA and the general Node acoustic levels even when the treadmill was not being used. The Acoustic MCTB ISS technology demonstration started in September 2016 and will continue until the MCTBs' surfaces become soiled and visually unacceptable as determined by crew preference. A continuation of the MCTB development is tentatively planned for FY19 for a low-mass crew quarters.More »
Test data with the flight Acoustic MCTBs indicated a decrease in the sound level by 2-3 dBA. Since dBA is measured on a logarithmic scale, a 3 dBA reduction is a halving of the sound energy. The MCTBs also reduced general cabin noise even when the treadmill is not being used.
For non-LEO missions, the vehicle interior volume will be relatively fixed. MCTBs will enable this volume to be used more effectively through reuse and rearrangement of logistical components. Reuse of cargo bags improves acoustics, habitation functionality, and reduces the packaging trash after the cargo bag contents are utilized.
|Organizations Performing Work||Role||Type||Location|
|Johnson Space Center (JSC)||Lead Organization||NASA Center||Houston, TX|
|White Sands Test Facility (WSTF)||Supporting Organization||NASA Facility||Las Cruces, NM|
|Materials Modification, Inc.||Industry||Fairfax, VA|