[MHU-5]
JAXA Mouse Habitat Unit Technical Verification

RESEARCH OVERVIEW

• The information on mouse physiology under partial G conditions contributes to the better understanding on the gravitational biology of mammals. This data provides important fundamental knowledge for the effects of partial G on the human body on future crew members on manned space exploration missions to the Moon, Mars, and beyond.
• The JAXA Mouse Habitat Unit-5 (MHU-5) obtains additional information on how partial G affects mouse physiology. In addition to the knowledge acquired on previous missions (in both microgravity and 1 G), further information is to be gained on the effects of partial G on mammalian physiology.

DESCRIPTION

The JAXA Mouse Habitat Unit-5 (MHU-5) investigation is focused on providing a better understanding of the impacts of partial gravity (partial G) on mice using a HCU that can be installed in the CBEF-L aboard the International Space Station (ISS). The purpose of this space investigation is to analyze any alterations of the gene expression patterns in several organs, and the effects on the germ-cell development of mice exposed to long-term partial G conditions (e.g. more than 30 days). Under partial G conditions, various types of stress could induce unusual gene expression patterns in somatic cells. Diverse adaptive responses to environmental changes in cells are also supposed to be elicited in a systematic manner.

This study could reveal the effects of long-duration spaceflight on mammals at the molecular level of gene expression and epigenetic modification. Data obtained from MHU-5 could suggest not only experimental information about mice exposed to the space environment in the long term, but also fundamental information for the long-term exposure of humans to partial G during future exploration missions to the Moon, Mars, and beyond.

SPACE APPLICATIONS

This study contributes to fundamental knowledge of how long-term space travel affects a model organism (mouse) at the level of gene expression and modification. Information about the effects of the space environment on mice can be applied to preparations for future long-term human space exploration.

EARTH APPLICATIONS

The investigation provides data that may contribute to development of countermeasures for muscle atrophy caused by extended bedrest or disease on Earth.

OPERATIONAL REQUIREMENTS AND PROTOCOLS

Before mice arrival, the Habitat Cage Unit (HCU) is attached in the Cell Biology Experiment Facility (CBEF) and checked out. Mice are transferred to the HCUs after hatch-open. For monitoring and analysis, the images and environmental data are downlinked as real-time as possible during the investigation. The data collected in the laptop computer is downlinked. The HCU Maintenance is done at regular intervals. The HCU Maintenance is four operations (Food Supply, Water Supply, Odor Filter Exchange, and Waste Collection), but if it cannot be performed all in one day, it can be carried out on other days. Mice are transferred to the Transportation Cage Unit (TCU) before hatch-closure.

Contingency operations are described in flight rules.

SHIBA Dai [JAXA]