Lessons Learned From Operations Planning and Preparation for EQUULEUS Launched Toward the Moon by SLS Artemis-1

EQUULEUS (EQUilibriUm Lunar-Earth point 6U Spacecraft) will be the world\u27s smallest spacecraft to explore around the Earth–Moon Lagrange point, which was launched on November 16, 2022, by NASA\u27s SLS (Space Launch System) Artemis-1. The primary mission of spacecraft is a trajectory control experiment, and its objective is to develop and demonstrate trajectory control techniques within the Sun-Earth-Moon region by flying to a libration orbit around the Earth-Moon Lagrange point L2 (EML2) along a low-energy transfer. EQUULEUS must perform a maneuver before the lunar flyby to stay within the Sun-Earth-Moon region. To perform DV1, we need to calculate and optimize the trajectory from launch to EML2. In addition, it is necessary to optimize the operation plan until the first lunar flyby, which is less than a week after launch. The reason for this is that the EQUULEUS trajectory will be significantly changed by the first lunar flyby, so appropriate trajectory control must be performed by that time. This paper presents the lessons learned in the operational preparation of EQUULEUS and those that should be applied to future missions to explore deep space, including the Moon and planets, by small and micro-satellites

EQUULEUS: Initial Operation Results of an Artemis-1 CubeSat to the Earth—Moon Lagrange Point

EQUULEUS is a 6U CubeSat developed by the Japan Aerospace Exploration Agency (JAXA) and the University of Tokyo, aiming to reach the Earth-Moon second Lagrange point (EML2) and perform scientific observations there. After being inserted into a lunar transfer orbit by SLS Artemis-1 on November 16, 2022, the spacecraft completed checkout operations and successfully performed a delta-V maneuver and subsequent trajectory correction maneuver. This enabled a precise lunar flyby as planned and successful insertion into the orbit toward EML2, which will take advantage of multiple lunar gravity assists and the gravity of the Sun. EQUULEUS is equipped with a water propulsion system newly developed by the University of Tokyo, and became the first spacecraft in the world to successfully control its orbit beyond low Earth orbit using water propulsion. The successful precise orbit control in the Sun–Earth–Moon region by EQUULEUS, a 6U CubeSat weighing only 10kg, has opened the possibility of full-scale lunar and planetary exploration by CubeSats. This paper describes the early operational results of EQUULEUS during its flight to EML2, with special emphasis on its precise orbit determination, guidance, and control results

Challenges and Operations to Re-Establish Communications With EQUULEUS After Loss of Contact During Its Cruise to the Earth-Moon L2 Point

EQUULEUS (EQUilibriUm Lunar-Earth point 6U Spacecraft) is a 6U CubeSat developed by the University of Tokyo and JAXA. It was launched on November 16, 2022, aboard NASA’s SLS Artemis-1 with the objectives of demonstrating orbital maneuvering capabilities in the cis-lunar environment and observing Earth’s magnetosphere plasma. After completing its major orbital maneuvers and achieving full mission success, communication with EQUULEUS was lost in 18th May 2023. Rapid fault tree analysis and optical observations using large telescopes indicated the spacecraft was likely in an uncontrolled tumbling state. Recovery operations were planned to re-establish communication by identifying potential times for sufficient solar power generation. This paper describes the details of EQUULEUS’s recovery operation

Flight Model Design and Development Status of the Earth - Moon Lagrange Point Exploration CubeSat EQUULEUS Onboard SLS EM-1

EQUULEUS (EQUilibriUm Lunar-Earth point 6U Spacecraft) will be the world’s smallest spacecraft to explore the Earth―Moon Lagrange point. The spacecraft is being jointly developed by JAXA and the University of Tokyo and will be launched by NASA’s SLS (Space Launch System) EM-1 (Exploration Mission-1). The spacecraft will fly to a libration orbit around the Earth―Moon Lagrange point L2 (EML2) and demonstrate trajectory control techniques within the Sun-Earth-Moon region for the first time by a nano spacecraft. This spacecraft also carries several scientific observation missions which will be conducted during and after the flight to EML2; imaging of the entire Earth’s plasmasphere by extreme UV wavelength, observation of the space dust flux in the cis-lunar region, and observation of the lunar meteor impact flashes at the far side of the moon from EML2. The development of the spacecraft started in the summer of 2016 and the engineering model integration and testing was completed by the end of 2017. The design of the flight model was completed based on the engineering model test results. The integration and testing of the flight model will be completed by the end of 2018, to be ready for the launch by SLS’ first flight in 2019