Major responsibilities of Astronaut Mukai

The main objective of the STS-95 mission is to acquire various kinds of data to identify the physiological effects of the zero-gravity environment to enable long-term space habitation. Astronaut Mukai is expected to contribute to this mission as an astronaut with a medical background.

Astronaut Mukai will assume the following major responsibilities.

Vestibular Function Experiment Unit (VFEU/NDAS)

Under the zero-gravity condition, the changes in signals received by the otolith of an oyster toadfish will be observed, and basic data on the causes of space sickness will be acquired.
The changes of the otolith of an oyster toadfish (neural activity potential data) will be continuously recorded from launch to landing. To stimulate the internal ear, the water container holding the oyster toadfish will be moved for once a day.
Astronaut Mukai is assigned to conduct these data acquisition related activities.

Plant Growth Experiment

The growth of plants under the zero-gravity condition will be observed to acquire data on the influence of the gravity to plants.
Plants are adapting to the gravity environment on Earth in various ways. In order to grow plants in space in the future, it is necessary to study these phenomena.
Astronaut Mukai is assigned to conduct plant experiments such as peg-formation of cucumbers, and will set the samples and observe and record the plant growth.

Sleep Experiment (SLEEP-2)

Since the space shuttle orbits the Earth in a cycle of about 90 minutes, daytime and nighttime alternately appear. Accordingly, the intrabody clock, which senses day and night can not function correctly, and presumably induces sleep disorder in astronauts.
Together with Astronaut Glenn, Astronaut Mukai will take "Melatonin" (a pineal body hormone reportedly effective for adjusting sleeping rhythm) every day and will record their breathing rates and electrocardiograms during the sleeping period. Sleep effect, condition of next day and quickness in motion, will also be checked.
This experiment is expected to add new data on the study of sleep-hindrance in astronauts.

Protein Turnover Experiment (PTO)

Protein is one of the most fundamental nutrients for humans to live. The experiment will acquire data on the protein metabolism in the overall human body and skeletal muscles during flight.
The experiment is expected to contribute to the study on nutrients necessary for long-term space habitations.
With her experience as a medical doctor, Astronaut Mukai will take Histidine (an amino acid structuring protein) and Heparin (a polysaccharide), collect blood samples, and separate the samples centrifugally.