Engineering math professor at @Virginia_Tech. Dynamics and transport, from spacecraft trajectories to airborne agricultural pathogens.
Virginia
Joined July 2015
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What if a spacecraft could cycle between Earth and Moon orbits, performing multiple circuits of each, naturally and indefinitely, with zero propulsion?
We’ve discovered a new class of stable, prograde, low-energy cycler orbits that do just that.
Why these orbits matter:
Ballistic → fuel-free
Stable → long-term ready
Near-chaotic → agile with low ΔV
Low-energy → access to Earth/Moon, Lagrange points, Sun–Earth L1/L2, even heliocentric space
At the AAS/AIAA Astrodynamics Specialist Conference in Boston next week, I’ll present on a new family of ballistic Earth-Moon cycler orbits that are stable, prograde, and mission agile—unlike any cyclers in the current literature.
The example below is shown in both the Earth-Moon rotating frame and inertial frame.
Conference Paper: ross.aoe.vt.edu/papers/ross-…
3D Earth-Moon cyclers in the real ephemeris with stationkeeping of about 6 m/s per month.
Found a linearly stable near-polar Earth-Moon cycler (CR3BP). Every 51.7 days it passes 8,500 km over the lunar south pole. Flown in DE440 with navigation and burn errors, it stays on track for a median 6.4 m/s/mo of delta-v. @RossDynamicsLab thought you'd enjoy this
Rocket pioneer Krafft Ehricke:
"If God wanted man to become a spacefaring species, He would have given man a Moon"
Of the major moons, only ours is heavy and distant enough for its manifolds to join the interplanetary highway
A lunar anthropic principle, from 4-body dynamics
This video was presented at the NASA-USGS Offworld Resources Workshop. Every curve in it is a computed trajectory, not an artist’s sketch.
1: Asteroid material arrives at the Rim, about 1.5 million km out, on natural paths into orbits around Sun-Earth L1 and L2.
2: From the Rim, refined material coasts to the Moon on gravity alone (~40 days) and is captured.
3: A few m/s burn puts it on an Earth-Moon cycler, which drops packages onto other orbits along its route.
The Earth-Moon system is threaded with natural routes like these. Find the right ones, and moving material around cislunar space costs tens of meters per second, not kilometers per second.
Ehricke's original reasoning was about lower gravity, oxygen/resources, & surface conditions as a first step outward.
The manifolds finding is a later celestial mechanics result he wouldn't have known, but confirms the Moon as uniquely well placed for low cost material movement
This video was presented at the NASA-USGS Offworld Resources Workshop. Every curve in it is a computed trajectory, not an artist’s sketch.
1: Asteroid material arrives at the Rim, about 1.5 million km out, on natural paths into orbits around Sun-Earth L1 and L2.
2: From the Rim, refined material coasts to the Moon on gravity alone (~40 days) and is captured.
3: A few m/s burn puts it on an Earth-Moon cycler, which drops packages onto other orbits along its route.
The Earth-Moon system is threaded with natural routes like these. Find the right ones, and moving material around cislunar space costs tens of meters per second, not kilometers per second.
Cycler and network orbits from my student Abdullah Braik’s PhD work.
Video: youtu.be/c_QzloeHTmk
Paper: arxiv.org/abs/2605.31543
Nice to see the Earth-Moon cycler orbits our lab recently discovered featured in @GarretsonPeter's overview of the cislunar space economy. Lots of interesting possibilities for transportation, surveillance, and infrastructure.
This is a fantastic video explaining orbital dynamics and the resulting economics, and security considerations of cislunar space. Well worth the 8.5 minutes to watch. youtu.be/kdpOdSMzXTA?is=By6z…
More on the stable Earth–Moon cycler orbits:
2025: Original discovery and applications
ross.aoe.vt.edu/papers/ross-…
2026: Underlying physics
arxiv.org/abs/2606.29189
Video: youtu.be/CgJE2hyC-mw
Listen to the point at the end: it's beyond mathematics.
Much of science, not just current science, but the planned scientific programs for a decade are being fed into the frontier models.
So a few companies know what scientists intend to do and where science is going.
Shane Ross retweeted
The 2027 SIAM Conference on Applications of Dynamical Systems (#SIAMDS27) has just posted its list of fantastic invited speakers: siam.org/conferences-events/…
This is the so-called "Snowbird Conference" (no matter where it's located) and is our home conference.
SpaceX has published its own visualization of the proposed Starmind constellation.
Left: SpaceX's. Right: the reconstruction I built in August from orbital parameters in its FCC filing, from the same viewpoint. Same narrow near-polar band of sun-synchronous orbits.
I only modeled the high-inclination sun-synchronous half. Their video also shows the low-inclination shells.
SpaceX shows it from space. I want to know what it looks like from the ground. They still don't report how bright these spacecraft will be.
sdross0.github.io/orbital-da…
SpaceX's Starmind visualization, on its Space Safety page (the video is partway down):
starlink.com/updates/space-s…
SpaceX wants up to a million satellites as orbital data centers. Half would ride the day-night line, sunlit while the ground below is dark.
Top and bottom are the same sky at the same moment. The only difference is how bright they're assumed to be.
@SciAm covered it today.
SpaceX has now published its own visualization of this constellation. The sun-synchronous orbits match what I reconstructed from their FCC filing:
xitter.cf/RossDynamicsLab/status…