STARFAB: Orbital Warehouse for In-Space Operations and Services (ISOS)

The STARFAB project, funded under Horizon Europe, is developing a concept for an orbital automated warehouse as the central infrastructure for OSAM (On-orbit Servicing, Assembly, and Manufacturing) and ISOS (In-Space Operations and Services). The focus is on a warehouse unit capable of reliably, safely, and scalably storing, transferring, and inspecting goods and resources in microgravity. -based manipulators and automated warehouse technology are designed to provide components, materials, propellants, and water for assembly, repair, refueling, and recycling in space. 

“An orbital automated warehouse serves as a central infrastructure for storage, maintenance, inspection, refueling, testing, recycling, assembly, and manufacturing in space.”
Niklas Ullrich, Research Scientist at Fraunhofer IML

Within STARFAB, a concept for an automated warehouse unit in orbit is being developed. This unit serves as a depot for components, materials, propellants, and water required for on-orbit servicing, assembly, testing, and recycling. An internal item handling system moves standardized storage containers between defined storage positions, while an item transfer system transfers them to docked spacecraft or other units. The storage technology is based on shuttle-based intralogistics systems and is specifically designed for microgravity. 

Relocatable robotic arms are to be used for the transfer of goods as well as for inspection and light maintenance. A walking manipulator handles key transfer tasks at the outer boundary of the warehouse unit; its drive and joint components are being further developed and tested to ensure they meet the requirements of future space missions. In addition, a mobile inspection module is being developed, equipped with a camera, 3D laser scanner, and thermal imaging sensors; an existing data fusion framework processes the data from this module to generate reliable findings for non-destructive testing. 

A ground-based demonstrator replicates the core functions of the STARFAB Warehouse Unit as a test setup. It combines structural segments, storage technology, robotics, and inspection modules and serves to test the concept on the ground. 

Integration with Warehouse Units

Conceptually, the Warehouse Unit is coupled with additional modules— , and —that are essential for a sustainable OSAM economy. These include, in particular:

• a Manufacturing and Assembly Unit (MAU) for in-space manufacturing and in-space assembly
• a Recycling Unit (RU) for processing space components or debris and providing valorized materials or residues.

Interfaces to cargo and service spacecraft 

STARFAB provides for docking/berthing interfaces to connect external spacecraft to the station:

• Cargo spacecraft arrive to resupply the WU with items and resources (e.g., components, payloads, raw materials, fuel, water),
• service spacecraft dock with STARFAB to receive support in the form of ORUs, fuel, or tools/robotics, and can additionally benefit from inspection and light maintenance services.

Mission configurations of the Warehouse Unit

 The STARFAB Warehouse Unit is considered in three mission configurations:

• Free-flying LEO platform with its own platform structure as the reference configuration
• As a facility module at a Commercial LEO Destination (CLD), permanently docked to a commercial space station

A key use case in the STARFAB project addresses servicer spacecraft that require Orbital Replacement Units (ORUs), propellants, and tools. A typical scenario begins with a cargo spacecraft delivering modular ORUs, raw materials, propellant, or water to the warehouse unit. The walking manipulator unloads these items and transfers them to the internal handling system, which stores them in appropriate storage zones. 

To extend a satellite’s lifespan, a servicer docks with the warehouse unit. The depot provides the required ORUs and fuel quantities. The internal automation system retrieves the appropriate containers, while the manipulator handles the transfer to the servicer. At the same time, the Mobile Inspection Module can inspect surfaces for debris damage, structural changes, and thermal anomalies. The Monitoring and Control Station on Earth plans the operations, simulates movements in the digital twin, and monitors their execution. 

Another use case involves the return of components or residues that are no longer needed. The Warehouse Unit collects these items and prepares them for transport. A cargo vehicle takes them for de-orbiting. In the future, a Recycling Unit will be connected to extract reusable materials from the waste. These materials can be stored again and later distributed to a Manufacturing and Assembly Unit or to service vehicles

The Fraunhofer Institute for Material Flow and Logistics IML contributes expertise in warehouse automation, shuttle systems, high-density storage, and AMR applications. Researchers analyze terrestrial warehouse technologies, evaluate their suitability for microgravity, and develop a concept that combines simplicity, robustness, storage density, and scalability. A shuttle-based approach is considered promising because it supports modular scaling from small to large systems. Experience from projects involving the automation of buffer warehouses, shuttle systems for various industries, and specialized solutions–such as those on ships–is incorporated into the evaluation of layouts, container concepts, and control strategies. 

Co-funded by the European Union