FAQ: In-Orbit Refueling Systems Initiative
Below are the questions we have been asked. If you query is not addressed, please send to: ior.project@reliqai.com Q1: What kind of details can you share about your new initiative? A1: This IOR initiative is a systems engineering architecture study focused on in-orbit refueling (IOR). It structures the problem from mission context and operational scenarios […]
1.9.0 Terminology and Definitions
[doc_toc] IOR Client satellite cooperation capability Levels Interface Enabled Satellite provides a compatible physical refueling interface allowing propellant transfer but does not actively participate in refueling operations. IOR Aware In addition to the physical interface, the satellite provides telemetry feedback to its ground system indicating refueling status and progress. IOR Aware must provide following controlled […]
1.9.5 Space Technical Knowledge
Propellants Electric Propulsion Propellants (Noble Gases) Primary propellants: Xenon Krypton Why? Used by almost all modern LEO constellations Increasingly used in GEO satellites Very high efficiency (high Isp) Ideal for orbit raising + station keeping Compatible with all-electric satellite platforms Storable Chemical Propellants (Hypergolic Family) Primary combinations: MMH + NTO UDMH + NTO Why still […]
1.9.4: Terms & Conditions, Timeline and License
Terms and Conditions Project Artifacts & Structure: Confluence and Jira are the source of truth. Web pages manage the review process. Contributor: Two contributors assist in Confluence/Jira updates based on their systems engineering and space project experience, and based on review comments. Reviewer: Reviewers post comments on IOR work pages. Comments, based on merit and […]
1.9.6 In-Orbit Refueling (IOR) Architectural Initiative
What Is This Project The IOR Architectural Initiative is an eight-week systems engineering project created to deliver a structured architectural decomposition of an In-Orbit Refuelling (IOR) system. Phase I applies a disciplined systems engineering process to define mission context, capture requirements, and develop a coherent system architecture. The initiative is vendor-neutral. Phase II, if pursued, […]
1.9.3 References
Normative References CONFERS: https://satelliteconfers.org/page/technical-committee-contributions CONFERS: Recommendations for Prepared In-Space (Re)Fueling Systems for Storable Propellants CONFERS: Recommendations for Best Practices, Functional Requirements, and Norms for In-space Servicing, Assembly, and Manufacturing (ISAM) Power and Data Interfaces NASA RPOD – https://www.nasa.gov/reference/jsc-rendezvous-prox-ops-docking-subsystems/ MERL – Safe and Constrained Rendezvous, Proximity Operations, and Docking- https://www.merl.com/publications/docs/TR2024-016.pdf Catapult – RPOD CONOPS https://d11avd6t8zdcx0.cloudfront.net/uploads/2025/09/RPOD-Report-v2.pdf Standards […]
1.9.2 Acronyms, Terms & Definitions
Acronyms AR&C – Autonomous Rendezvous and Capture. DSO – Dynamic Space Operations. ECEF – Earth-Centered Earth-Fixed. Used for ground locations. ECI – Earth Central Inertial – uses for orbits, spacecraft trajectory. GGNS – Guidance, Navigation and Control System. GN&C – Guidance Navigation and Control. T&M – Telemetry and Monitoring. ISAM – In-space Servicing, Manufacturing, and […]
1.9.1 Naming Convention
[doc_toc] Naming Convention OPCON Stages Examples OPC-LAUNCH OPC-ORBIT_INSERT OPC-STANDBY OPC-RENDEZVOUS OPC-PROXIMITY_OPS OPC-DOCKING OPC-PROP_TRANSFER OPC-UNDOCKING OPC-RETURN OPC-DISPOSAL Requirements IOR-<LEVEL>-<CATEGORY>-NNN LEVEL STKR = Stakeholder Requirement MISR = Mission Requirement SYSR = System Requirement DERR = Derived Requirement VERI = Verification Requirement HSWR – High Level Software Requirement LSWR – Low Level Software Requirement CATEGORY Discipline grouping OPEC […]
1.9 Appendix
Naming Convention OPCON Stages Examples OPC-LAUNCH OPC-ORBIT_INSERT OPC-STANDBY OPC-RENDEZVOUS OPC-PROXIMITY_OPS OPC-DOCKING OPC-PROP_TRANSFER OPC-UNDOCKING OPC-RETURN OPC-DISPOSAL Requirements IOR-<LEVEL>-<CATEGORY>-NNN LEVEL STKR = Stakeholder Requirement MISR = Mission Requirement SYSR = System Requirement DERR = Derived Requirement VERI = Verification Requirement HSWR – High Level Software Requirement LSWR – Low Level Software Requirement CATEGORY Discipline grouping OPEC = […]
1.8 Boundaries and Interfaces
Document/Purpose External and Internal Interfaces defined Traceability (Upstream /Downstream) Documents Upstream: Downstream: System Requirements Status DRAFT – Ready for Review Baseline Version/Date Current Version Not yet established | v0.1 04 Mar 2026 Last Updated 23 Mar 2026 Owner / Lead Sanjay Chadha Contributors Reviewers Scope/Out-Of-Scope Scope: System Design, System Requirements, System Analysis, Out-of-Scope: Physical Architecture […]