## 6 Operations  
The SE01 CubeSat was launched, together with other 27 QB50 satellites, on 18 April 2017, on an Atlas-V rocket as part of a resupply mission to the International Space Station (ISS). The remaining eight QB50 satellites were launched on 26 June of the same year to a polar orbit on an Indian Polar Satellite Launch Vehicle (PSLV). The SE01 CubeSat was deployed into orbit from the ISS on 17 May. From that moment the development team was granted a period of seven weeks to complete the launch and early operations (LEOP) phase for commissioning all subsystems and payloads. The LEOP phase starts with the early discrimination phase that usually should not last more than one week to check whether the satellite survived the launch, and identify the satellite among all other satellites that may have been deployed simultaneously. Additional checks can be performed to find out whether all appendages have been deployed, and the solar panels supply enough power to operate the CubeSat. The North American Aerospace Defense Command (NORAD) is the organization responsible for tracking and cataloging all celestial bodies in orbit. The NORAD organization publishes a list of all civil satellites and their two-line element (TLE) sets, which can be accessed from Reference [53]. During the discrimination phase, NORAD publishes the TLEs of unrecognized satellites, which can be distinguished through the NORAD catalog number, e.g., 42708 or the Committee on Space Research (COSPAR) designator, e.g., 98067 LR. The first orbital elements are published no more than 5 h after the CubeSat flies over NORAD's radars. Discrimination occurs when operators can unambiguously identify their satellite as the body in the catalog with the orbital elements, in order to be able to successfully track and communicate with the satellite. The LEOP phase continues with a platform commissioning and detumbling phase. In this phase, all subsystems of the CubeSat are checked for their correct function in orbit. Care should be taken to guarantee that satellite operations are not disrupted by the tests. Particularly, ADCS is a critical subsystem for the success of the mission, and is very sensitive to commissioning tests. The satellite may have some rotations induced by the deployment mechanism during orbit insertion. The CubeSat has to be detumbled to a stable attitude. Such detumbling operation is usually performed by magnetorquers. Once the satellite is stable, other actuators such as reaction wheels can take over for fine attitude control required for nominal operations. The LEOP finalizes with the commissioning of the payloads. Operators calibrate the instruments, and perform tests to check for the payload function, power consumption and transmission of science data for safe nominal operations. The communications window for common CubeSats in the LEO is about 12 min per pass in the best-case scenario. In practice, however, the quality of a pass is very sensitive to the environmental factors as well as maximum elevation of the satellite as seen from the ground station. In the case of SE01's operations, any pass with maximum elevation below 15\({}^{\circ}\) would not be considered due to the short time, less than 5 min, and the high amount of communication errors. Such a criterion made three passes as the average of daily observations. However, SE01's orbit drifted daily in a way that high-quality passes occurred during the same time in a cycle of two months. This implies that for one month operations occurred late at night. Such a change in schedule should be planned in advance for organizing observation shifts. Given the limitations in the amount of information that can be sent through an amateur radio channel, it is recommended to use multiple ground stations, in order to maximize the data exchange between the satellite and its operators. Many CubeSat developers have established their own ground station, and would be willing to enhance communication opportunities with their satellites through networking with other ground stations.