Cislunar Explorers: Lessons Learned from the Development of an Interplanetary CubeSat

The Cislunar Explorers mission is a pair of ~3U nanosatellites (named Hydrogen and Oxygen) launching as a single 6U CubeSat as part of NASA’s Artemis-1 mission on the Space Launch System (SLS). The two spacecraft will demonstrate technologies increasing the reach, flexibility, and cost-effectiveness of interplanetary smallsats. These innovations include water electrolysis propulsion, multi-body optical navigation, passive spin-stabilization, and the operation of femtosatellites beyond low earth orbit. Cislunar Explorers also serves as a pathfinder for demonstrating the utility and versatility of water for future In Situ Resource Utilization (ISRU) on space missions. Critical subsystems complement each other to reduce the cost and complexity. Water not only serves as the propellant for the propulsion system, but also as a radiation shield, electronics heat sink, and nutation damper. Each spacecraft’s spin provides attitude stabilization, separates electrolyzed gas from the water in the propulsion tank, simplifies the active attitude control system, and enables the optical navigation system to cover a panoramic view around the spacecraft. The unique elements of the mission spacecraft’s design provided advantages to traditional CubeSat architectures but also produced unexpected development challenges. By leveraging the lessons learned from the development of the Cislunar Explorers mission, future interplanetary missions can utilize its technology to reduce cost, risk, and complexity