Abstract: Atomic Oxygen （AO） in Low Earth Orbit （LEO） induces severe oxidative erosion on spacecraft surface materials, degrading performance and shortening operational lifespan. Discrepancies persist between AO flux values predicted by thermospheric models and actual in-orbit measurements. Current AO sensor fabrication techniques—magnetron sputtering, cathodic plasma discharge, and screen printing—exhibit distinct limitations: magnetron-sputtered carbon films are typically ultrathin （<a few micrometers）, surviving less than three months at 400 km altitude; cathodic plasma discharge yields thicker films but entails complex equipment and high costs. In contrast, screen printing offers simplicity, cost-effectiveness, and the capability to produce robust thick films. This study develops a thick-film AO sensor using domestically sourced carbon paste via screen printing, achieving a uniform carbon layer of approximately 25 μm thickness. In this paper, “thick carbon film” specifically denotes screen-printed films ranging from 10 to 50 μm, significantly exceeding the nanometer-to submicrometer-scale thickness of conventional magnetron-sputtered counterparts and thereby extending in-orbit service life. Sensor performance is evaluated using an AO simulation facility. Results demonstrate a linear relationship between the pre- to post-exposure resistance ratio （R₀/R） and cumulative AO flux （F）, confirming the sensor’s suitability for quantitative AO flux measurement. Extrapolation from experimental data indicates a maximum detectable AO flux of 5.8×10²¹ atoms·cm⁻². This work establishes screen printing as a viable, economical method for fabricating durable AO sensors with enhanced operational longevity in LEO environments.