## 1 Introduction
There are several indices defined for measuring nitrogen content in plants with a lot of success. However, not much work is identified to estimate nitrogen content in coastal waters. Nitrogen Indices are robust spectral transformations of two or more spectral bands, of which at least one is directly or indirectly related to Nitrogen content [5]. One commonly used index is the Normalized Difference Nitrogen Index (NDNI), which is a log10 transformed reflectance Nitrogen Index (NI) that is based Nitrogen's absorption feature at 1510 nm and a reference band at 1680 nm [5]. Furthermore, the SWIR region can also be used to map through aerosols, especially dust efficiently. Visible imagers are frequently incapable of seeing through fog, haze, smoke, and dust, contract to the capabilities of the longer wavelengths of the short-wave infrared that are more capable of penetration in such conditions and hence provide better imaging quality. At the same time, longer wavelengths in the SWIR region (\(>\)2000 nm) can be used to detect dust and characterize mineralogical information. Apart from this, the SWIR bands have been used for accurate atmospheric correction of visible and very near-infrared bands of sensors such as MODIS [6]. This experiment can also validate those measurements apart from providing complementary information to the information obtained from the camera on-board the proposed CubeSat and UAE satellites such as DubaiSat-1 [7], DubaiSat-2 [8], and KhalifaSat [9] images. The primary payload of MeznSat is the Argus 2000 SWIR spectrometer, which is a miniature, low-cost, space-certified spectrometer that operates in the near-infrared bands (1000 nm to 1650 nm) [1]. MeznSat's secondary payload is a High Definition camera that will allow post-processing to achieve the high geolocation accuracy required for the spectrometer. This setup of using visible and SWIR spectrometer together with a visible-optical imaging camera will generate an interesting dataset to explore atmospheric correction algorithms which employ SWIR data to process visible channels. The MeznSat spacecraft bus design consists of an attitude determination and control system (ADCS), a power system, a Command and Data Handling (CDH) System, a communications system and the structure. The ADCS is required to achieve an accuracy of less than 1 degree due to the narrow Field of View (0.15 degrees) of the Argus 2000 spectrometer [10]. The ADCS uses three reaction wheels and three magnetic torquers for control, and sun sensors, a horizon sensor and a star tracker for attitude determination. The CDH consists mainly of an On-Board Computer board with an ARM9 processor, 64 MB SDRAM and two SD cards for mass storage. The power system design includes 22 solar cells capable of producing 6.5 Watts of average power. The satellite's communications system consists of a UHF transmitter for the downlink, a VHF receiver for the uplink and a set of deployable dipole antennas. The most relevant CubeSat projects include the CANX-2 mission [11] and the SathyambaSat mission [12]. CANX-2 is a 3U CubeSat mission that was launched in 2006 and uses the same spectrometer but does not carry an RGB camera on-board. SathyambaSat is a 2U CubeSat that was launched in 2016. SathyambaSat uses the ARGUS 1000 spectrometer as its only payload, and it has a moderate ADCS system, which relies on magnetic actuation [12]. While there are several similar missions reported in the literature, this is the first mission that uses Shortwave Infrared Spectrometer in combination with an RGB camera and a reactive attitude control system capable of less than 1-degree accuracy on a 3U form factor. The advantage of having the RGB Camera with the spectrometer is for geolocation. In a previous paper, we provided an overview of the initial MeznSat design [1]. In this paper, we present a detailed description of the final MeznSat mission concept, analysis, and design, including a comprehensive overview of the spacecraft bus.