Ozonometer-TM instrument for “Ionosphere-M” spacecrafts

Within the framework of “Ionozonde-2025” project, Ozonometer-TM instrument for the monitoring of the Earth's ozonosphere has been created. The instrument is part of payload of the “Ionosphere-M” spacecrafts # 3 and # 4, which are to be launched in 2025.

The goal of the instrument is to monitor total ozone from the satellite orbit by means of nadir measurements of reflected and scattered light. The instrument is a spectrometer of UV-visible light [1] operating in the wavelength range of 300–500 nm with a spectral sampling of 0.1 nm and resolution 0.3–0.4 nm. The spectral range of the instrument allows monitoring not only ozone, but also other gases, such as nitrogen dioxide, in the Earth's atmosphere.

During the development of the spectrometer, a number of prototypes were manufactured and a few series of ground-based measurements were carried out. Estimates of the total ozone column were obtained, and the results were compared with the data of the nearest independent measurements from the satellites [2]. Up to now, the instrument has gone through a full cycle of ground tests; two flight models are now ready for launch. In addition to spectral calibration, absolute radiometric calibration have been carried out for the flight models of the instrument using a standard of spectral concentration of a radiance.

In addition, an "extended" modification of the spectrometer, called Ozonometer-Z, is expected to be installed onboard the “Zond-M” spacecraft. This version of the instrument is a spectrometer with an ultra-wide field of view (100 degrees). It also has a higher luminosity compared to Ozonometer-TM. Ozonometer-Z consists of two channels: a UV channel (300–400 nm) and a VIS channel (400–800 nm). Unlike the Ozonometer-TM, which has a one-pixel field of view, the Ozonometer-Z is an imaging spectrometer with about 200 resolvable elements across the trajectory of the spacecraft [3]. Accordingly, instead of the linear detector used in the Ozonometer-TM, the Ozonometer-Z is supposed to be equipped with a CCD or CMOS matrix. The calculated spectral resolution is as high as 0.3 nm in the UV channel and 0.5 nm in the VIS channel. The optical scheme of both channels of the Ozonometer-Z instrument has been developed to date.

Literature

1. Dobrolenskiy Y.S., Ionov D.V., Korablev O.I., Fedorova A.A., Zherebtsov E.A., Shatalov A.E., Mantsevich S.N., Belyaev D.A., Vyazovetskiy N.A., Moiseev P.P., Tchikov K.N., Krasavtsev V.M., Savushkin A.V., Rumyantsev D.M., Kananykhin I.V., Viktorov A.I.,  Kozyura A.V., Moryakin S.A., Poberovskii A.V. Development of a space-borne spectrometer to monitor atmospheric ozone // Applied Optics, 2015, v. 54, № 11, pp. 3315 – 3322.
2. Dobrolenskiy Y.S., Ionov D.V., Korablev O.I., Fedorova A.A., Zherebtsov, E.A., Shatalov A.E., and Poberovskii A.V. Ground-Based Field Measurements and Calibrations of a New Satellite Spectrometer for Monitoring the Earth’s Ozone Layer // Izvestiya, Atmospheric and Oceanic Physics, 2018, Vol. 54, No. 9, pp. 1399 – 1407.
3. Dobrolenskiy Y.S., Dziuban I.A., Ivanov Y.S., Syniavskyi I.I., Ionov D.V., Poberovsky A.V., Korablev O.I., Fedorova A.A., Vyazovetskiy N.A. Optical Design and Modeling of Satellite Imaging Spectrometer for Atmosphere Monitoring // Proc. SPIE, 2019, Vol. 11180, pp. 1118065-1 – 1118065-9.