A microwave-oven-size spacecraft has completed NASA’s work after nearly four years of testing around the Moon. CAPSTONE did more than trace an unusual lunar orbit: it tried software that can determine a spacecraft’s position with less help from Earth and networking that preserves data through broken connections. Its private owner will continue using the craft as a technology testbed.
CAPSTONE turned one small satellite into several experiments
The spacecraft launched in June 2022 to test technologies needed for future lunar operations. It became the first spacecraft to fly and characterize a near-rectilinear halo orbit, a looping path influenced by the gravity of Earth and the Moon that can be maintained with relatively little fuel.
NASA’s July 6 mission report says CAPSTONE achieved all primary and extended objectives. After its initial work, a 15-month extension turned the existing hardware into a platform for communications, networking, autonomous navigation and software-defined satellite tests.
Reusing an operating spacecraft allowed engineers to test new applications in the actual lunar environment without building and launching a separate satellite for every demonstration. That approach can lower costs and reveal interactions that may not appear when technologies are tested alone.
Navigation software learned to work with less ground contact
The autonomous Navigation, Guidance and Control software, called autoNGC, was designed to determine where a spacecraft is, where it is headed and how to reach its destination without waiting for instructions from Earth. CAPSTONE marked the first test of the system at the Moon.
During periods with limited ground contact, the software used an onboard star-tracker camera to image the Moon, Earth and other celestial bodies. NASA reported that this optical-navigation method sometimes outperformed ground-based techniques for real-time onboard positioning.
Autonomy matters because deep-space communications are limited by distance and competition for antenna time. A craft that can estimate its own state and continue safely through a gap reduces its dependence on continuous direction from controllers. Future traffic around the Moon could make that ability increasingly valuable.
The test became more demanding when NASA’s Deep Space Network was supporting the Artemis II crewed flight around the Moon. CAPSTONE sometimes received only a few communications passes each week. That scarcity turned an operational constraint into evidence: the navigation software had to keep producing useful position estimates during the periods when ground-derived data were unavailable.
A broken connection did not lose the data
CAPSTONE also tested delay and disruption tolerant networking, or DTN. Unlike an ordinary internet connection that expects a continuous path, DTN stores information when a link disappears and forwards it when communications return.
In one test, contact with Earth ended before a transmission finished. The spacecraft retained the remaining information and automatically resumed during the next opportunity. NASA says every piece of the data arrived.
The experiment became the first flight of the latest DTN protocols beyond Earth orbit and the first to run them inside NASA’s core Flight System. A common open-source framework can make the result useful beyond one spacecraft because later missions can adapt the same architecture.
A store-and-forward network also changes how missions can share infrastructure. Orbiters, landers and surface users may not all see Earth or one another at the same time. If each node can hold a data bundle until a route becomes available, information can move through a lunar network without requiring every link to exist simultaneously.
The unusual orbit was part of the technology
The NASA mission overview describes CAPSTONE as the Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment. Its orbit is relevant to plans for longer-term activity near the Moon, where communications geometry, fuel use and access to the lunar surface must be balanced.
A small commercial spacecraft demonstrated that such an orbit could be entered, maintained and characterized before larger, more expensive missions rely on similar paths. It also supplied a real environment for testing technologies that would behave differently under laboratory conditions or in low Earth orbit.
NASA finished, but the spacecraft did not
NASA concluded its CAPSTONE activities in June 2026 after nearly four years of technology maturation. Advanced Space owns and operates the spacecraft and plans to keep using it as a development platform. Terran Orbital designed and built the craft.
The handoff illustrates a commercial model in which a private operator can continue extracting research value after an agency’s objectives are complete. The hardware remains in space, its software can host new applications and its operational history reduces some uncertainty for later experiments.
CAPSTONE’s legacy is therefore larger than its size. It showed that navigation and communications software can be changed, combined and tested around the Moon on hardware already in flight. As lunar activity grows, missions that can locate themselves and preserve data through interrupted links will require less constant attention from Earth.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
More from Morning Overview
