Mice Drawer System (MDS): procedures performed on-orbit during experiment phase

Mice Drawer System is a payload that can be integrated inside the Space Shuttle middeck during transportation to/from the ISS, and inside the Express Rack in the ISS during experi-ment execution. It is designed to perform experiment as much automatically as possible; only maintenance activities require procedures involving crew. The first MDS experiment has been performed with Shuttle STS-128, launched in August, 28 2009 at EDT time 23:58 (06:58 Italian time). During the permanence in the Shuttle, MDS was switched on in SURVIVAL mode, cooled by air from rear part of the middeck: this mode allows to supply water and night-and-day cycles to mice in automatic mode, but not food that was supplied ad libitum before launch by a dedicated food bar inserted inside the cage. In this phase, a visual check has been performed every day by crew to verify the well-being of the mice. During the permanence in ISS, MDS was switched on in EXPERIMENT mode, cooled by water from EXPRESS RACK. In this case, MDS experiment was completely automatic: water, food, night-and-day cycles were commanded every day by the payload. Only Maintenance activities to replace consumable items and to fill the potable water reservoir were foreseen and executed by the crew. Food Envelope replacement was foreseen every 19 days, the Waste Filter replacement has been performed every 30 days. Potable Water Reservoir refilling has been performed every 9 days. Nominal activities performed on ISS were also the transfer from Shuttle to ISS and reconfiguration from ascent to on-orbit operation after launch. The reconfiguration from on-orbit to descent and transfer from ISS to Shuttle has been performed before Shuttle undock and landing.