A300 ZERO-G Airbus
The objective of the OUM (Oxygen Uptake Measurement) experiment is an operational evaluation, providing insight into procedures implementation and hardware functionality of ISS medical operations with respect to Periodic Fitness Evaluations (PFE) using the Pulmonary Function System (PFS). In order to maintain crew health during long-duration missions on ISS, regular health checks must be performed, including assessments of the cardiovascular fitness status with a cycle ergometer. Technical limitations have impeded the conduct of these assessments with oxygen uptake measurement, as they were originally foreseen in the international medical requirements for the ISS, and currently, only an indirect measurement of fitness using heart rate during an exercise protocol is used. Oxygen consumption measurements and metabolic calculations are known to be gold standards for fitness evaluations.
Since the OUM will be a new activity on ISS, there are several unknown factors, such as time required to go through the procedures, comfort issues, confinement, hardware performance and other potentially unexpected effects due to weightlessness. These have to be considered before actually implementing the activity for the first time in orbit. Indeed, many of these factors are only based on assumptions during the development of procedures and crew training lessons.
Our experiment shall identify and highlight unexpected problems with respect to time required to implement the OUM procedures and their comfort and practicability. These have not yet been tested in a weightlessness environment, but they will be integrated in the crew training sessions, and implemented in orbit during the upcoming ESA long duration mission.
Additionally, PFS hardware functionality in weightlessness will be tested. The oxygen measurement device was developed by DAMEC, a European company, and provided to the ISS community by the European Space Agency. Once this new device is commissioned and fully integrated on ISS, it is planned to be used by the international partners as well, for health and fitness evaluations.
The OUM gas analysis system comprises different sensors and capture systems allowing a variety of uses for different purposes in the field of expired gas measurements, pulmonary ventilation and flow rate, and the calculation of metabolic parameters. The main entities of the system are the PFM/PAM (Pulmonary Function Module/Photoacoustic Analyzer Module), which is called PFS (Pulmonary Function System), the GASMAP (massspectrometer) and the GDS (Gas Delivery System). These components allow the detection of O2, CO2, C2H2, CH4, R-22, SF6 as well as air flow measurements. To enhance the spectrum of measured parameters, various systems, i.e. blood pressure and heart rate measurement devices, plethysmograph, and laptops can be attached to the PFS System. The data of all attached devices (i.e. CEVIS, BP/ECG, etc) are synchronized within the system, thus enabling precise data evaluation and interpretation, and saving crew time. In our experiment we test the set-up and tear-down/stow procedures according to the procedures prepared for the crew training protocol. In imitating the conditions of a weightless environment on a parabolic flight, we want to identify at an early stage potential weaknesses of the procedures and the hardware. Documenting and comparing the time used for the same procedures under microgravity and normal gravity conditions, and observing handling problems during the execution shall give insight about the quality of the protocols used.
These findings will be forwarded to the multilateral PFS working group and could potentially influence the preparation of the crew training with PFS and the on-orbit procedures, as well as trigger hardware changes to the PFS system.