2024-06-202024-06-202024-07-21ICES-2024-46https://hdl.handle.net/2346/98769Wenyan Li, NASA Kennedy Space Center, USATesia Irwin, NASA Kennedy Space Center, USAPhilip Wood, NASA Kennedy Space Center, USADeborah Essumang, NASA Kennedy Space Center, USAAngie Diaz, NASA Kennedy Space Center, USANilab Azim, NASA Kennedy Space Center, USAMichael Callahan, NASA Johnson Space Center(JSC), USAChad Morrison, NASA Johnson Space Center(JSC), USAEvan Neidholdt, NASA Johnson Space Center(JSC), USAICES406: Spacecraft Water/Air Quality: Maintenance and MonitoringThe 53rd International Conference on Environmental Systems was held in Louisville, Kentucky, USA, on 21 July 2024 through 25 July 2024.Total organic carbon (TOC) is the amount of carbon associated with organic compounds in solution and is often used as a non-specific indicator for water quality or cleanness. Currently, the Total Organic Carbon Analyzer (TOCA) is being used onboard the International Space Station (ISS) for both water recovery system process control and for human health and performance monitoring. An exploration-class TOCA is now being developed to close the technology gaps between the State-of-the-Art (SOA) ISS TOCA and the emerging requirements of future exploration missions. One of the technical gaps for an exploration TOC analyzer is the development of suitable methods for on-orbit calibration. While the ISS TOCA uses pre-packaged ground-supplied TOC calibration standards, there is limited stability data using this approach. Other options include preparing calibration standards in space, which can be challenging due to the lack of low TOC reagent water. This paper explores the practice of the standard addition method and passive dosing approaches as potential solutions to overcome this problem.application/pdfengTOC Analyzercalibration methodcalibration standardsstandard addition methodpassive dosingPresentations