Scientists at Lawrence Livermore National Laboratory simulated one million satellite orbits in the vast stretch of space between Earth and the Moon, and fewer than one in ten survived the full six-year test. The results, published in Research Notes of the American Astronomical Society, offer the first large-scale open benchmark for understanding which paths through cislunar space hold steady and which spiral into chaos. With NASA’s Artemis program and a growing roster of private lunar ventures planning missions through this region, the findings carry immediate practical weight for anyone designing a spacecraft meant to last.
One Million Paths, Six Years Each
The team, led by Travis Yeager alongside co-authors Denvir Higgins and McGill at Lawrence Livermore, used LLNL’s in-house astrodynamics solver, SSAPy, to integrate one million orbits from a fixed starting point and propagate each one forward up to six years. That time horizon matters because it exceeds the planned duration of most near-term lunar missions, giving engineers a stress test rather than a snapshot. Each trajectory was modeled with high-degree Earth and Moon gravity fields, solar gravity, and radiation pressure, according to the technical manuscript. The researchers also noted certain designed omissions to keep computational costs manageable, such as neglecting tiny perturbations from other planets, meaning the real cislunar environment is even more unforgiving than these simulations suggest.
What emerged was stark. Roughly 54% of the orbits remained stable for at least one year, but that number dropped sharply over time as small perturbations accumulated. By the end of the full six-year window, only about 9.7% of orbits survived, according to the peer-reviewed paper. The steep attrition reflects a basic reality of cislunar dynamics: the gravitational tug-of-war between Earth, the Moon, and the Sun creates a chaotic environment where small differences in starting conditions can send two nearly identical orbits on wildly divergent paths within months. In practical terms, this means that long-lived cislunar missions cannot rely on “set and forget” trajectories; they must plan for regular station-keeping maneuvers and robust navigation strategies from the outset.
182 Years of Computing in Three Days
Generating one million six-year trajectories at high fidelity is not something a desktop workstation can handle. The effort consumed 1.6 million CPU-hours, a workload equivalent to more than 182 years on a single computer. LLNL’s supercomputers Quartz and Ruby compressed that into roughly three days of wall-clock time, demonstrating how modern high-performance computing can turn what would once have been a generational research project into a long-weekend run. The speed advantage comes from SSAPy’s architecture, which is written to exploit massive parallelism on distributed-memory machines and to scale efficiently as more processors are added.
That distinction is not just a technical footnote. Most commercial orbit-propagation tools run sequentially, meaning they handle one trajectory at a time, whereas SSAPy splits the work across thousands of processors simultaneously, which is what made a million-orbit campaign feasible in the first place. The implication for the broader space community, highlighted in coverage from Phys.org, is that large-scale Monte Carlo-style surveys of orbital stability, previously impractical, can now be completed in days rather than decades. Gravity modeling fidelity also played a role: LLNL scientists emphasized that failing to account for the uneven mass distribution, or “blobbiness,” within Earth would make even GPS satellites drift unpredictably, undermining meter-level accuracy for navigation and underscoring how small modeling errors can snowball over multi-year timescales.
An Open Dataset for a Crowded Frontier
Rather than keeping the results locked behind institutional walls, LLNL released the full output as an open database called CISLUNAR Orbit Data. The dataset includes 1,000,000 numerically propagated cislunar trajectories available as downloadable CSV summaries and full HDF5 time-series files. That format choice is deliberate: CSV files let analysts quickly filter and sort orbits by stability duration or initial conditions, while HDF5 files preserve the complete state vector at each time step for researchers who need granular detail. Each record ties back to a common initial epoch and a consistent force model, giving the community a rare apples-to-apples comparison set across an enormous slice of phase space.
Open access to a dataset of this scale could shift how mission planners and defense analysts approach cislunar space domain awareness. A recent preprint on cislunar dynamics points out that predicting long-term behavior beyond geostationary orbit is exceptionally difficult because of overlapping gravitational influences and the lack of large reference datasets. LLNL’s million-orbit library directly addresses that gap. For commercial operators designing lunar relay satellites or logistics depots, the data provides a quick way to screen candidate orbits before investing in expensive, bespoke simulations. For defense agencies tracking objects in cislunar space, the dataset offers a baseline catalog of what stable and unstable trajectories actually look like over multi-year timescales, improving the ability to distinguish routine behavior from anomalies that might signal a maneuvering spacecraft.
Why 90% Failure Rates Matter for Lunar Ambitions
The headline number, that fewer than 10% of orbits endured the full six years, deserves scrutiny rather than alarm. Most planned cislunar missions, from crewed Artemis flights to robotic landers and communications relays, are designed around lifetimes of months to a few years, not six. In that context, the finding that more than half of the simulated orbits remain viable for at least a year is actually encouraging. The key takeaway is not that cislunar space is unusable, but that long-lived, low-maintenance orbits are rare and must be chosen with care. Mission designers who know where those “islands of stability” lie can deliberately target them, trading slightly more complex insertion maneuvers for years of reduced fuel consumption.
At the same time, the high attrition rate is a warning against complacency as traffic to the Moon increases. As more spacecraft occupy cislunar space (scientific platforms, navigation beacons, commercial tugs, and potentially debris), understanding which orbits are naturally self-clearing and which tend to trap objects for years will shape both safety standards and regulatory frameworks. The LLNL simulations show that many trajectories either crash into Earth or the Moon or are flung into heliocentric orbits within a few years, which could help planners design disposal strategies that minimize long-term clutter. For policymakers and engineers alike, the million-orbit benchmark turns an abstract gravitational battleground into a quantifiable design space, offering a data-driven foundation for the next decade of lunar ambitions.
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*This article was researched with the help of AI, with human editors creating the final content.
