Browsing by Author "Stodieck, Louis"
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Item A CO2 controller enabling cell culture research inside automated incubator onboard the ISS(46th International Conference on Environmental Systems, 2016-07-10) Tozer, Stuart; Stodieck, Louis; Hoehn, Alexander; Anthony, JonathanThe majority of all Earth-based mammalian tissue and cell culture research is conducted in “CO2 incubators” where both the air temperature and concentration of carbon dioxide is precisely controlled to ensure optimal cell growth. In particular, the concentration of CO2 is important for controlling the pH level of the cell culture’s media and to reproduce in-vivo CO2 conditions. This paper describes the design and performance of a CO2-control system to enable cell culture work on board the ISS in combination with a temperature-controlled incubator. Precise on-orbit environmental control provides the means for reproducible inflight and mission-parallel ground control experiments so that spaceflight experiments can be directly compared with the terrestrial body of work. The on-orbit cell culture work is conducted using incubators developed at the University of Colorado. The incubator platform, the Space Automated Bioproduct Lab (SABL), is a mid-deck locker size payload that controls the incubator temperature to set-points ranging from -5°C to +43°C. The Atmosphere Control Module (ACM) is an insert specifically designed to fit on the back wall of SABL’s incubator chamber and to maintain the CO2 concentration to a set-point, typically 5%, with an incubator temperature of 37°C for most cells. The ACM holds 400g of CO2, enough to support 15 weeks of continuous experiments, based on the incubator’s CO2 leakage rate to ambient cabin. This paper will discuss ACM’s design challenges, including the storage and dispensing of supercritical CO2 and safe pressure-conditioning hardware required for a controlled release of CO2 gas. The ACM will launch on SpaceX’s CRS-9 mission in March 2016 along with its first cell culture experiments. This paper will discuss the safety and flight qualification and performance testing of ACM on ground in addition to, as available, on-orbit performance of the ACM during the first to be conducted experiments in spring 2016.Item AEM-E – A small life support system for the transport of rodents to the ISS(44th International Conference on Environmental Systems, 2014-07-13) Niederwieser, Tobias; Gerren, Richard; Koenig, Paul; Tozer, Stuart; Stodieck, Louis; Rieger, Sebastian; Hoehn, AlexanderCurrent resupply carriers to the ISS, such as the Dragon or Cygnus capsules, do not yet support replenishment or control of atmosphere constituent altered by respiration of living cargo. In order to transport animals for scientific experiments to the ISS, an Environmental Control and Life Support System is therefore needed. The newly developed Animal Enclosure Module–Environmental Control (AEM-E) payload supplements the AEM-T animal carrier and was designed to compensate the respiration-induced changes by replenishing the consumed oxygen to the cabin atmosphere and by removing metabolically produced carbon dioxide and moisture. AEM-E takes a desiccant-based approach to remove moisture with silicon dioxide and carbon dioxide with lithium hydroxide. For the oxygen supply, a novel gaseous oxygen replenishment system was designed. The functionality of the AEM-E was verified under worst-case load conditions in subsystem and integrated tests with simulated and actual mice in an isolated environment for up to 10 days and up to 20 mice. This paper discusses quantitative and qualitative test results of the subsystem and integrated tests. Activity- and time-dependent air composition and respiration data from the isolated environment during the integrated flight-simulation tests are presented. The system has undergone flight certification and safety assessment and is planned to be flight-ready in late 2014.Item Design and Flight-Qualification of an Oxygen Resupply System to Support the Transport of Live Rodents to the ISS(44th International Conference on Environmental Systems, 2014-07-13) Tozer, Stuart D.; Koenig, Paul; Niederwieser, Tobias; Stodieck, Louis; Hoehn, AlexanderThe transport of live rodents to the ISS aboard a pressurized commercial cargo resupply carrier, such as SpaceX Dragon or Orbital Cygnus, requires safe and reliable delivery of gaseous oxygen. This paper will present the oxygen system design for the Animal Enclosure Module – Environmental Control (AEM-E) payload, which has undergone flight certification and safety assessment and is planned to be flight-ready by early 2014. To support an animal load of 20 mice or 6 rats and a maximum mission duration of 10 days, up to 875 liters (1.26 kg) of oxygen are required. The first design challenge was to safely store this amount of oxygen within the limited volume of a middeck-locker-sized payload. The minimum risk design uses four small composite cylinders, each containing 183 liters oxygen (at ambient pressure), compressed to 20 MPa (3,000 psig). The four independent tanks provide redundancy while limiting risk from any single tank failure. Each of the four oxygen tanks is passively flow-restricted using a precision micro-orifice (25 micron diameter), reducing the risk of cabin overpressurization or exceeding safe oxygen levels – even under catastrophic failures. For a low-power and robust oxygen release mechanism, a novel oxygen-compatible wax-actuated valve was developed and certified. Using less than 4 watts each, the 20 MPa-rated valves can be opened and closed reliably. Individual electrolytic partial pressure oxygen sensors provide the control inputs to independent analog band gap controllers for each wax-actuated valve. Oxygen concentrations are controlled with a high setpoint at nominal oxygen concentrations (20.9%) and a low setpoint at 19.6%, as required for docking to the ISS. A unique analog circuit prevents activation of more than one oxygen tank at any one time, further reducing risk from system malfunctions. System qualification of the ‘Design for Minimum Risk’ oxygen resupply system will be presented, together with system validation and integrated performance test results.Item Implementation of Lithium Hydroxide as a Dual CO2/H2O Scrubber for a Rodent Research Life Support System(48th International Conference on Environmental Systems, 2018-07-08) Anthony, Jonathan; Hoehn, Alexander; Niederwieser, Tobias; Stodieck, Louis; Tozer, StuartAEM-E (Animal Enclosure Module – Environmental Control) was developed as a middeck locker payload to provide life support for rodent research in space. The AEM-E design has recently been upgraded to double its original rated capacity, now supporting 40 mice or 12 rats over a 10-day mission while maintaining its original single-locker form factor. A key enabling design modification in achieving this considerable performance increase was to combine the relative humidity (rH) and carbon dioxide (CO2) scrubber systems using a single lithium hydroxide (LiOH) scrubbing architecture. LiOH is a well-known CO2 scrubbing material with life support applications dating back to the first manned space missions. LiOH reacts with cabin atmospheres via hydration (reversibly producing LiOH·H2O) and carbonation (irreversibly producing Li2CO3). Despite a rich background of research relating to LiOH carbonation, relatively little research has been reported on LiOH hydration with most studies only focusing on its role as a catalyzing reaction for carbonation. Compared to other desiccants such as silicon dioxide (SiO2), LiOH offers superior volume and mass efficiency. Based on this, LiOH was selected as the primary humidity and CO2 scrubbing material for the updated AEM-E design, which we believe to be the first reported spacecraft life support application of LiOH where humidity control is a primary function. This paper discusses the empirical formulation of a dual CO2/H2O absorption model for LiOH and its integration into a multi-scenario mission simulation alongside other AEM E components and rodent metabolic models. Underactuated single-input multiple-output (SIMO) control is a key implementation challenge of dual CO2/rH control with LiOH and requires a specific metabolic envelope of CO2 and H2O output rates to function acceptably. However, based on the work presented herein, the dual control scheme is expected to satisfy AEM-E’s operational requirements.Item Microfluidics-integrated spaceflight hardware for measuring muscle strength of Caenorhabditis elegans on the International Space Station(2022) Soni, Purushottam (TTU); Anupom, Taslim (TTU); Lesanpezeshki, Leila (TTU); Rahman, Mizanur (TTU); Hewitt, Jennifer E (TTU); Vellone, Matthew; Stodieck, Louis; Blawzdziewicz, Jerzy (TTU); Vanapalli, Siva A (TTU)Caenorhabditis elegans is a low-cost genetic model that has been flown to the International Space Station to investigate the influence of microgravity on changes in the expression of genes involved in muscle maintenance. These studies showed that genes that encode muscle attachment complexes have decreased expression under microgravity. However, it remains to be answered whether the decreased expression leads to concomitant changes in animal muscle strength, specifically across multiple generations. We recently reported the NemaFlex microfluidic device for the measurement of muscle strength of C. elegans (Rahman et al., Lab Chip, 2018). In this study, we redesign our original NemaFlex device and integrate it with flow control hardware for spaceflight investigations considering mixed animal culture, constraints on astronaut time, crew safety, and on-orbit operations. The technical advances we have made include (i) a microfluidic device design that allows animals of a given size to be sorted from unsynchronized cultures and housed in individual chambers, (ii) a fluid handling protocol for injecting the suspension of animals into the microfluidic device that prevents channel clogging, introduction of bubbles, and crowding of animals in the chambers, and (iii) a custom-built worm-loading apparatus interfaced with the microfluidic device that allows easy manipulation of the worm suspension and prevents fluid leakage into the surrounding environment. Collectively, these technical advances enabled the development of new microfluidics-integrated hardware for spaceflight studies in C. elegans. Finally, we report Earth-based validation studies to test this new hardware, which has led to it being flown to the International Space Station.Item SABL – An EXPRESS locker-sized incubator for performing biological experiments onboard the ISS(45th International Conference on Environmental Systems, 2015-07-12) Niederwieser, Tobias; Anthony, Jonathan; Darnell, Asa; King, Geoffrey; Koenig, Paul; Stodieck, Louis; Wright, Jim; Gahbler, Philipp; Hoehn, AlexanderThe Space Automated Bioproduct Lab (SABL) is an EXPRESS locker-sized incubator developed by BioServe Space Technologies for use on the International Space Station (ISS). SABL provides a 41.9 x 27.9 x 19.4 cm (16.6” x 11.1” x 7.8”, DxWxH) sized science research module (SRM) volume, which can be temperature-controlled from -5 to +43 °C. SABL improves over the Commercial Generic Bioprocessing Apparatus (CGBA) in several aspects including higher thermal ramp rate, lower thermal gradients, enhanced experiment control, software adaptability, and crew interaction. SABL is designed to accommodate a variety of existing legacy life sciences hardware that was previously used with CGBA, enabling SABL to function as a flexible lab for biological experiments in microgravity. This paper focuses on the thermal design of the payload as well as on the verification testing of the engineering unit. The design process for SABL focused on minimizing thermal gradients within the SRM volume, improving thermal ramp rates between temperature set points, and eliminating the usage of forward facing cabin air exhaust systems that produce unacceptable acoustic noise. Temperature control of the SRM is accomplished using a total of four thermoelectric coolers (TECs) mounted to the top and bottom surfaces of the SRM. SABL utilizes the EXPRESS Moderate Temperature Loop (MTL) as a thermal sink for the TECs and avionics. Thermal feedback control and safety monitoring is implemented using a suite of sensors that interface to an NI sbRIO-9636 data acquisition and control computer. Performance of the engineering unit was characterized to verify thermal models of operation, cooling/heating times, and robustness against uneven internal heat loads and off-nominal operation. After starting development in 2011, the first two SABL units are manifested to launch to the ISS onboard SpaceX CRS-8 in the fall of 2015.