Dispelling the Myth of the Universal Interface: Results and Inferences From an Evaluation of In-space Connectable Interfaces

Arkisys is developing a long-duration orbital platform – The Port Module – capable of accepting arrivals of new payloads, technologies, components, etc. As a unique platform the method of connectivity becomes the critical attribute that requires a deep understanding and operational experience base, which translates into what is a “connectable interface”. On the path to understand and select connectable interfaces that allow for commercial operations, in early 2021 Arkisys conducted a survey of legacy, new, and currently-in-development physical interfaces for in-space connection. This survey included 33 devices, focusing on aggregate-able post-post launch connection, and the quality of that connection. Interfaces were evaluated on technical, safety, and business viability attributes. In 2025, Arkisys conducted an updated evaluation to reflect the current landscape of physical interfaces for use in in-space operations, including In-space Servicing, Assembly, and Manufacturing (ISAM). This study evaluated 38 interfaces across four functional areas, dropping several interfaces from the 2020 study which didn’t make it to market, and adding several emerging interfaces from 2020-2025. Information was collected regarding these interfaces through publicly available channels. Neither survey considered human-rated docking interfaces, as these have been studied in detail by NASA for use on the International Space Station and Lunar Gateway, which we determined may be not practical for robotic ISAM use at their current size and mass/volume. If, in the future, scaled down variants of these interfaces are available, the results of this study will be updated to include these new interfaces. This latest study was meant to combine the results of the two studies and use the data to determine commonalities and functional similarities in the designs, as well as identify suitable real-world use cases for each of these interfaces. From the results of the study and the analysis performed, first analysis pointed away from a single common interface for ISAM (i.e. a “USB for Space”) and instead towards a subset of interfaces that were optimized for niche tasks. This paper will dive into the data and analysis to discuss.