Synopsis
The document describes the Lockheed Martin In-space Upgrade Servicing System (LM LINUSS), a pair of small satellites designed to demonstrate rendezvous and proximity operations capabilities for future on-orbit servicing missions. The LM LINUSS satellites are part of Lockheed Martin’s LM50 family of 12U CubeSats, measuring about 8x8x12 inches each. They were launched into geosynchronous orbit in November 2022 as secondary payloads on a SpaceX Falcon 9 rocket.
The goal of the LM LINUSS mission is to validate maneuvering and navigation capabilities needed for future spacecraft upgrade and servicing missions, as well as demonstrate miniaturized space domain awareness technologies. The satellites carry technologies developed by Lockheed Martin, Terran Orbital, Innoflight, and VACCO. Key capabilities include over 20 m/s of delta-V, concurrent attitude and trajectory control, far field acquisition and proximity operations imaging, and closed loop guidance, navigation and control.
The LM LINUSS satellites completed several technology demonstrations while on orbit. This included rendezvous and proximity operations missions with increasing autonomy, leveraging Lockheed Martin’s Horizon command and control software. They also showcased Lockheed Martin’s SmartSat on-orbit software upgrade architecture. The onboard computer vision system enabled far field acquisition, unresolved centroid collection, and multi-camera calibration using images of the Earth.
Overall, the LM LINUSS mission accelerated learning for spacecraft rendezvous and docking capabilities. The program demonstrated robust ground operations for managing two vehicles concurrently with a small crew. It also highlighted challenges related to maintaining state knowledge, thermal management, star tracker performance, replanning for loss of contact, and other real-world operational constraints.
To build on this demonstration, Lockheed Martin has released an open standard interface for on-orbit docking called the Augmentation System Port Interface (ASPIN). This will allow future upgrades to spacecraft’s hardware capabilities after launch. Ground tests have already demonstrated ASPIN docking with CubeSats.
The Space Operations and Simulation Center (SOSC) at Lockheed Martin’s Colorado campus was critical for developing and testing LM LINUSS. This large indoor facility can simulate proximity maneuvers and docking events. It provides a flexible lab environment for maturing rendezvous and proximity operations algorithms and technologies.
In summary, the LM LINUSS mission successfully demonstrated key capabilities to enable future spacecraft servicing and upgrade missions. Lessons from this demonstration will be applied to progress safe and sustainable on-orbit operations.