IAC 2025: Responsive RPO for Commercial Application

Rendezvous and Proximity Operations (RPO) are essential for on-orbit servicing (OOS) applications such as inspection, repair, upgrades, life extension, and orbit relocation. Recently, interest has grown in responsive RPO, which aims to accelerate system preparation and in-orbit operations. While defense needs—such as rapid threat assessment— have driven much of this demand, responsive RPO also holds strong commercial potential. This paper explores the value of responsive RPO for commercial use and the key challenges to enable it. Responsive RPO allows operators to quickly address anomalies through emergency inspections, repairs, and recovery support. Each year, multiple satellite failures occur where such emergency on-orbit services could be effective, indicating potential market demand. Long procurement cycles of OOS force operators to make uncertain forecasts, whereas a more agile approach—where RPO systems are deployed shortly after a request—enhances the readiness of OOS benefits. Currently, RPO demonstration missions require several years for development, verification, manufacturing, launch, and in-orbit operation. To make responsive RPO viable, these phases must be shortened without compromising safety. Unlike cooperative missions (e.g., with the ISS), emergency OOS often targets non-cooperative, non-predetermined objects, requiring robust safety measures to avoid collisions. Key technical challenges include developing versatile and robust relative navigation and automation of trajectory and operation planning. Cost efficiency is also critical. Reusing the Servicer Vehicles across multiple Client objects improves economics, but servicing multiple Client objects requires extensive time-of-flight and delta V to perform potentially large orbital transfers. Advancements in high-thrust electric propulsion and refueling technologies are needed to overcome delta V limitations and long times-of-flight. Addressing these challenges will unlock scalable, responsive RPO solutions for the growing commercial OOS market.