# HYPSO-1 CubeSat: First Images and In-Orbit Characterization
## 2 Mission and Payload Operations  
The HYPSO mission aims to make agile and near real-time oceanographic observations to support marine research. To achieve this, the ability to capture and downlink data over the desired area with a quick response time, relative to existing satellite systems, has been  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Value** & **Comment** \\ \hline
**Orbit** & & \\ Orbital Altitude & 540 km & Will decrease gradually. \\ Inclination & 97.5\({}^{\circ}\) & Local Time Descending Node 10.30, \\ Orbit Period & 97 min & global coverage. \\ \hline
**Payload** & & \\ Image Sensor & CMOS & Sony IMX249 LIJ in IDS breadboard PCB. \\ Pixel Size & 5.86 \(\upmu\)m & size of square sensor elements. \\ Sensor Pixel Grid & 1936 \(\times\) 1216 & 1936 spectral, 1216 spatial. \\ Image Sensor bit depth & 12 bits & Binning sums 9 spectral pixels. \\ Slit Width & 50 \(\upmu\)m & See [23; 24]. \\ IFOV Along-track & 0.056\({}^{\circ}\) & See [523]. \\ IFOV Across-track & 7.883\({}^{\circ}\) & See [5; 23], illuminating at most 1216 px. \\ Main Spectral Range & 400-800 nm & See [23; 24]. \\ Grating Grove Density & 300 grooves/mm & Transmission grating, see [23; 24]. \\ Blaze Angle of Grating & 17.5\({}^{\circ}\) & Center wavelength @ 600 nm. \\ Spectral FWHM & 3.33 nm & Theoretical Value, see Section 3.3. \\ Spatial Swath Width & 40 km, 70 km & nominal and max respectively, see [23]. \\ \hline
**Data Volume** & & \\ Nominal Sensor Area Used & 1080 \(\times\) 684 & 1080 spectral, 684 spatial, see Section 3.2. \\ Nominal Frame Rate & up to 22 Hz & Dependent on capture configuration. \\ Nominal Exposure Time & 10–45 ms & See Section 2.3. \\ Nominal capture Time & 43.45 s & 956 frames / 22 fps = 43.45 s. \\ \hline
**Performance** & & \\ Ground Sampling Distance & 64 m across, & Dependent on viewing geometry, See \\  & 350 m along & Section 3.1. \\ Along Track Length & 330 km & Depending on capture configuration. \\ Spectral Range & 430–800 nm & See Section 3.2 and [24]. \\ Spatial FWHM & \textless{}2.2 pixels & Across-track, see Section 3.1. \\ Spectral FWHM & 5.2 nm & Before binning, see Section 3.2. \\  & @ 480–530 nm & See Section 3.5. \\ SNR Estimate & \textless{}300 & \\  & @ 450–500 nm & \\ \hline \hline \end{tabular}
\end{table}
Table 1: An overview of HYPSO-1 parameters. Certain values were originally discussed in [5; 23; 24].  
important when defining the requirements for the mission. From [5], the following mission Goals are established:  
**Goal 1:** Data latency should be less than 1 h [25];  
**Goal 2:** Revisit times to dedicated areas of interest should be 3-72 h [25; 26].  
_Data latency_ is the time from when an observation is performed until the final data products are distributed [5]. However, as the full pipeline to obtain the complete data products has not yet been finalized, the _response time_ is more relevant to discuss in this paper. In this paper, the _response time_ is defined as the time from receiving an image request until a capture is planned, uploaded, and performed by the satellite.  
The revisit time is the time between successive overpasses with line-of-sight to a target area. In this paper, we elaborate on the _effective revisit time_, the time between two consecutive imaging operations of the target area by HYPSO-1. The effective revisit time for optical earth observation payloads depends on the time of day, the geographical location, as well as the time of year for targets at latitudes higher than the polar circles. As an example, polar areas can be observed from a sensible angle up to four times a day with 1.5 hr intervals during summer, but during winter, they cannot be observed due to lack of sunlight.  
In the following sections, the operational architecture and operations workflow are described and then illustrated with examples showing selected operational capabilities of HYPSO-1.