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HARDWARE INFORMATION

Animal Enclosure Module (AEM)
Hardware Type
Habitat Facility, Rodent

Description
The Animal Enclosure Module (AEM) is a rodent housing facility that supports up to six 250 g rats. The unit fits inside a standard Shuttle middeck locker with a modified locker door. A removable divider plate provides two separate animal holding areas, if required. The AEM remains in the stowage locker during launch and landing. On orbit the AEM may be removed partway from the locker and the interior viewed or photographed through a Lexan cover on the top of the unit. With addition of an Ambient Temperature Recorder temperatures at up to four locations within the unit can be recorded automatically.

Subsystems

Air Quality: Cabin air is exchanged with the AEM through a filter system. Four fans create a slight negative pressure inside the AEM ensuring an inward flow of air and particulate entrapment by the treated outlet filter. Cabinet air is drawn through front panel inlet slots, then along the side plenum walls to the rear of the AEM, and then through the inlet filter, across the cage/animal habitat area, through the exhaust filter, and exits the front of the AEM. High efficiency air (inlet and outlet) filters (electrostatic and phosphoric acid-treated fiberglass pads) prevent the escape of particulate matter into the cabin atmosphere. Treated charcoal inside the filters helps contain animal odor and neutralize urine within the AEM. The filter system is rated for 20 days of odor control.

Lighting: Four internal incandescent lamps (two used as backup) provide illumination and are controlled by an automatic timer to provide a standard 12:12 light/dark cycle. The timer is programmable for other light/dark cycles and a backup battery maintains the timer if AEM power is disrupted. Only two lamps are used during the light cycle to keep cage compartment heating to a minimum. The lamps are covered with clear caps to protect them from animal debris and breakage.

Food: Rodent food bars are attached to four slide-in food bar plates inside the rodent cage. The food, a sterilized laboratory formula (standard or PI formulated), is molded into rectangular bars accessible to the animals at all times during the mission.

Water Refill Box: The AEM accommodates an internal water supply containing four lixit drinking valves and two flexible plastic bladders for water storage. Water pressure is maintained in the bladders via compression springs. Remaining water can be observed through the Lexan window on top of the water box.

Water Refill Line: The AEM Water Refill Line (WRL) is used for inflight refill of the drinking water in the AEM. It allows direct transfer of potable water from the auxiliary port of the Shuttle Orbiter Galley without the need for a special pumping device.

Components of this System:

Air Filter System
Cabin air is exchanged with the unit through a filter system. Four fan blowers, operated by a switch on the front panel, create a slight negative pressure inside the cage, causing an air sweep to pull animal waste products into a collection filter. Cabin air is drawn through the front panel inlet slots, then along the side plenum walls, to be directed though the inlet filter located at the rear of the AEM, into the animal habitat. High efficiency particulate air filters (electrostatic and phosphoric acid treated fiberglass pads) prevent any microbiological escape into the cabin atmosphere. Treated charcoal, within the unit, confines animal odors within the closed system. After exiting the habitat through the exhaust filter, located at the front of the unit between the rodent cage and fans, the filtered air is drawn through the fans into the cabin and directed by the air deflector. Air flow indicator ribbons are attached to both sides of the air deflector for visual confirmation of AEM air flow.

Lighting
The four internal lamps provide an average of 14 lux illumination and are controlled by an automatic timer to provide a 12-hour lighting cycle. The lamps are mounted two to a side in the rear corners of the AEM, between the animal habitat and inlet filter, and are covered with a clear cap to protect each lamp from animal debris and to contain glass if lamp breaks. Although the 12-hour cycle is fixed, the starting hours, minutes, and day/night sequence can be selected.

Water
The unit has a 1500- and 200-cc capacity automatic watering unit that utilizes four “Lixit Drinking Valves” and two flexible plastic (polyvinylchloride) bladders for water storage. Sufficient water pressure is maintained via compression springs. Looking through the Lexan cover and into the water box lid, the amount of water remaining can be seen since the lid is enscribed with a numeral 0 in the center, and the numerals 1 through 4 in both directions for gauging water consumption.

Versions of this Hardware
+ Version Used During Space Shuttle Missions
+ Version Used on NIHR3
+ Version Used on Neurolab

Components of this Hardware
Air Filter System
Cabin air is exchanged with the unit through a filter system. Four fan blowers, operated by a switch on the front panel, create a slight negative pressure inside the cage, causing an air sweep to pull animal waste products into a collection filter. Cabin air is drawn through the front panel inlet slots, then along the side plenum walls, to be directed though the inlet filter located at the rear of the AEM, into the animal habitat. High efficiency particulate air filters (electrostatic and phosphoric acid treated fiberglass pads) prevent any microbiological escape into the cabin atmosphere. Treated charcoal, within the unit, confines animal odors within the closed system. After exiting the habitat through the exhaust filter, located at the front of the unit between the rodent cage and fans, the filtered air is drawn through the fans into the cabin and directed by the air deflector. Air flow indicator ribbons are attached to both sides of the air deflector for visual confirmation of AEM air flow.

Lighting
The four internal lamps provide an average of 14 lux illumination and are controlled by an automatic timer to provide a 12-hour lighting cycle. The lamps are mounted two to a side in the rear corners of the AEM, between the animal habitat and inlet filter, and are covered with a clear cap to protect each lamp from animal debris and to contain glass if lamp breaks. Although the 12-hour cycle is fixed, the starting hours, minutes, and day/night sequence can be selected.

Water
The unit has a 1500- and 200-cc capacity automatic watering unit that utilizes four "Lixit Drinking Valves" and two flexible plastic (polyvinylchloride) bladders for water storage. Sufficient water pressure is maintained via compression springs. Looking through the Lexan cover and into the water box lid, the amount of water remaining can be seen since the lid is enscribed with a numeral 0 in the center, and the numerals 1 through 4 in both directions for gauging water consumption.

Food
Standard rodent food bars are attached to four slide-in food bar plates inside the rodent cage. The food, a sterilized laboratory formula, is molded into rectangular bars (approx. 1.875 x 1 x 8 inches) accessible to the animals at all times during the mission.

Water Refill Box
The Animal Enclosure Module Refill Box is a supplementary hardware item used to replenish the drinking water in the AEM for longer duration missions (greater than 5 days). The Refill Box can store and deliver up to 2250 milliliters of water. The refill box is made up of an aluminum box which houses the pump/motor assembly and the water volume which is held in three polyvinylchloride bladders. Located on the exterior of the box is the power switch, power connector and cable, and the flexible fluid line and connection which interfaces with the AEM fill port. The Refill Box receives its power from a connector provided on the AEM on the upper left hand side of the front panel. The Refill Box can be stored within one half of a middeck locker volume. A selector valve is used to select the bladder from which water will be drawn. Water is then pumped from the bladder through the quick disconnect fitting and out the flex line where the coupling interfaces with a male nipple on the AEM. Water is then pumped through a selector valve on the AEM and into the AEM water box. An additional water line is provided in the event that even more water is needed. This 24 foot flexible Teflon tube has a stainless steel overbraid and interfaces with the auxiliary port of the Shuttle Orbiter Repackaged Galley (SORG) and is able to transfer water from the shuttle drinking water system directly to the AEM without the need for additional pumping hardware.

Muffler
The AEM Muffler is a new item in the Life Science Laboratory Equipment (LSLE) suite to be used for inflight sound dampening. The Muffler is designed to reduce the noise emitted from the AEM fans to meet Shuttle middeck payload specifications. The proposed AEM Muffler design consists of a Nomex fabric covered Melanine foam on the inner surface, backed by a 1/16" thick Aluminum plate, SoundFoil, and 1/32" thick Aluminum plate, with a final Nomex fabric cover on the outer surface of the assembly. The Muffler will be attached to the front of the locker door using Velcro attachments. The AEM Muffler will be installed on the locker after achieving orbit and stowed prior to re-entry.

Ground Support Equipment
Three items of commercial Ground Support Equipment (GSE) are used to support functional checkout and testing of the AEM. Two of the items, a Millipore Vacuum Pressure Pump and a Dispensing Pressure Vessel, are used to fill the AEM water bladders. The dispensing vessel is rated to 100 pounds per square inch gauge (psig) and the vacuum pump is capable of delivering 60 psig. However, the pump is regulated to deliver less than 25 psig in order to fill the AEM water bladders prior to flight. There is a pressure relief device on the dispensing vessel set at 100 psig and the hoses are rated for the maximum operating pressures. A commercial, UL approved, 28 VDC power supply is used for AEM power during functional testing. The power supply is attached to the AEM via standard power cables.

Nursing Facility
The AEM Nursing Facility accommodates lactating rat dams and their litters in flight. Each AEM Nursing Facility contains two suites, each one housing one lactating female and up to 10 neonates. Each suite is made up of two connected chambers, a den and a nest, that are divided by a partition. The suites are separated from each other by a false floor and walls, so that two families live in each Nursing Facility.