This article describes a novel procedure and algorithm used for the in-flight calibration of the Thermal Infrared Sensor (TIRS) onboard the Mars 2020 mission. The purpose is to recalibrate the responsivity of TIRS’ IR detectors as they degrade following surface operations and exposure to harsh environmental conditions. Using data from in-flight calibration campaigns conducted through sol 800 of this mission, we report the time evolution of the responsivity for the different IR detectors, as well as the final performance achieved by the algorithm in the real operating environment. Moreover, we analyzed changes in responsivity as a function of TIRS geometric design and environmental factors, e.g., detector orientation, direct exposure to prevailing winds and solar radiation, electrostatic properties of the detector filter, and atmospheric dust concentration. We concluded that dust deposition on the detectors' filter during landing, and later during operation is the most likely cause of the degradation observed in the various channels, with gravitational sedimentation and the capacity of the filters to accumulate electrostatic charge being key factors. The relative and absolute degradation of the TIRS is similar to those reported by other Martian missions and instruments with similar orientations, and to date, it has shown no signs of cleaning after more than a year on the surface of Mars. Accounting for changes in responsivity during the mission is critical to maintaining the reliability of TIRS measurements, which will later be made available in NASA's Planetary Data System for the benefit of the scientific community.

中文翻译：

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NASA Mars2020 任务中 MEDA-TIRS 仪器的飞行校准


本文介绍了一种用于火星 2020 任务中热红外传感器 （TIRS） 飞行校准的新程序和算法。目的是重新校准 TIRS 红外探测器的响应度，因为它们在表面操作和暴露于恶劣环境条件后会退化。使用通过此次任务的 sol 800 进行的飞行校准活动的数据，我们报告了不同红外探测器响应度的时间演变，以及算法在实际操作环境中实现的最终性能。此外，我们分析了响应度随 TIRS 几何设计和环境因素的变化，例如探测器方向、直接暴露于盛行风和太阳辐射、探测器过滤器的静电特性和大气灰尘浓度。我们得出结论，探测器过滤器上着陆期间以及随后运行期间的灰尘沉积是在各种通道中观察到降解的最可能原因，其中重力沉降和过滤器积累静电荷的能力是关键因素。TIRS 的相对和绝对退化与其他具有类似方向的火星任务和仪器报告的情况相似，迄今为止，它在火星表面停留一年多后没有显示出清洁的迹象。考虑任务期间响应度的变化对于保持 TIRS 测量的可靠性至关重要，稍后将在 NASA 的行星数据系统中提供，以造福科学界。