Science in Short: Building a Better Gas Trap

PBRE is is the largest, most complex experiment installed in the MSG to date. Credits: NASA
PBRE is is the largest, most complex experiment installed in the MSG to date. Credits: NASA

The Packed Bed Reactor Experiment (PBRE) was installed in the Microgravity Science Glovebox (MSG) this week, and is the largest, most complex experiment installed in the MSG to date. When the gas-control module did not power up properly, NASA astronaut Tim Kopra helped to quickly identify the problem, which involved a foam piece imbedded in a connector. Kopra also helped trouble-shoot a video camera for the gas-liquid separator. After two days of setup, all systems in the PBRE are now operating as expected.

During subsequent testing, PBRE found that the gas flow provided by the MSG was not as high as desired. The team is still evaluating if the test matrix will need to be modified. Initial testing this week includes some preliminary flows to flood the column with water and then introduce low gas flows to observe viscous fingering within the porous media (similar to water injected into oil wells to enhance flows).

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Next week, PBRE will begin a series of tests to determine minimum flows to remove bubbles from the reactor bed. This is a serious concern encountered by most reactor beds in microgravity, since gravity is not available to drive the bubbles to the top of the reactor. Our results will provide guidelines to design and operating beds to prevent bubble accumulation.
In space, water-recovery systems, fuel cells and other equipment use packed bed reactors, but currently none are designed to handle both liquid and gas at the same time. With improved understanding of how packed bed two-phase flow works in microgravity, scientists are be able to design more efficient, lightweight thermal management and life support systems that use less energy, benefiting the Space Station as well as future lunar and Mars missions.

On Earth, design rules for gas-liquid flows through packed columns are well developed, but lacking for reduced or zero gravity. PBRE seeks to fill this knowledge gap by studying the hydrodynamics of gas-liquid flows in zero gravity through packed columns. By understanding how gravity affects gas-liquid flows through packed columns (or packed beds, as they are known in the industry) better, more predictive correlations for pressure drops and flow regime maps can be developed with the proper gravity-dependent terms included.

David Brady Assistant ISS Program Scientist
David Brady
Assistant ISS Program Scientist

Science in Short: A Milestone in Human Research

Lead Expedition Scientist Yuri Guinart-Ramirez presented the following research highlights at the 45 Soyuz Return/47 Soyuz Launch And Dock Stage Operations Readiness Review held on June 2.

European Space Agency (ESA) Tim Peake, performs Ocular Health fundoscope exam aboard the International Space Station. Credits: NASA
European Space Agency (ESA) Tim Peake, performs Ocular Health fundoscope exam aboard the International Space Station. Credits: NASA

We know human spaceflight is entrenched with dangers and risk to our astronauts, from their vision and eye health, to their musculoskeletal system and immune system, among many other risks. Did you know that out of 36 long-duration crew members, there were 15 clinical cases detected with issues related to vision? In other words, 41.6% of long-duration crew members developed vision issues with various degrees of symptoms. That is a high percentage. Understanding these and the many other effects that microgravity has on the body is key for us to continue to venture beyond low-Earth orbit and be more successful on long-duration spaceflight. We want to go further into space, and so we must answer these fundamental medical issues and continue develop more effective countermeasures.

The good news is that we are getting a little closer.

The upcoming return of 45S will mark the completion of the in-flight portion for four NASA investigations in the Human Research category – Ocular Health, Cognition, Salivary Markers and Microbiome; and that is big milestone. Once the post-flight baseline data collection takes place, we will have completed the required number of subjects for these four investigations. It takes a long time to complete the number of subjects required for Human Research investigations – it’s usually years in the making – so this is a big milestone.

Cognition will help us understand how the physical changes related to spaceflight such as microgravity, stress, and lack of sleep can affect cognitive performance. The results can lead to more effective ways of measuring the effect on cognitive ability during long-duration spaceflight.

NASA astronaut Kjell Lindgren works through 10 cognitive tests developed to test how spaceflight affects mental abilities. Credits: NASA
NASA astronaut Kjell Lindgren works through 10 cognitive tests developed to test how spaceflight affects mental abilities. Credits: NASA

Salivary Markers and Microbiome are both searching for a better understanding of the effect of microgravity on the immune system. Salivary Markers – as the name hints, focuses on saliva. But why saliva? Because our saliva is amazing! Our saliva has antimicrobial enzymes and antibacterial properties that kill some bacteria, and that helps us remain healthy. Immune system dysregulation has been documented during and after spaceflight, but it is not known if these changes increase infection susceptibility or pose a significant health risk to crew members. Salivary Markers is helping us understand that. Microbiome is assessing the immune system by studying the collection of microbes in the body and gut area that also help us stay healthy, and its interaction with its environment. Understanding that micro-universe of microbes, its balance needed to keep us healthy, and its interaction with the space station environment will also help us develop more effective countermeasures.

Of course, these four investigations have a good variety of applications for medical and health issues we face here on Earth. As we prepare to celebrate the safe return of the 45S crew, let us also celebrate the completion of these four Human Research investigations as another stepping stone on our journey beyond low-Earth orbit and healthier long-duration spaceflight.

Yuri Guinart-Ramirez Lead Increment Scientist Expeditions 47 & 48
Yuri Guinart-Ramirez
Lead Increment Scientist
Expeditions 47 & 48