Shane Ross

Humble engineering math professor at @Virginia_Tech. Nonlinear dynamics, orbital mechanics, and the geometry of motion // @Caltech PhD

[Shane Ross @RossDynamicsLab]

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: https://t.co/v3VDPIT0X4

[Shane Ross @RossDynamicsLab]

@JaguarCat_ What would you consider long-term stable?

[Shane Ross @RossDynamicsLab]

Nine families of Earth–Moon cyclers, stable orbits that ferry back and forth between the two, forever. 🌍♾️🌙

In the rotating frame each one closes up and repeats. The label (k₁,k₂) counts the loops: k₁ around the Earth, k₂ around the Moon. Periods run ~42–106 days.

[Shane Ross @RossDynamicsLab]

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: https://t.co/v3VDPIT0X4

[Shane Ross @RossDynamicsLab]

@astro_campr @L5Resident From LEO, it’s slighter cheaper for the Delta-V to do flybys of Venus instead of Mars. Time of light is about 5 months one-way. The flyby itself costs almost nothing. You just need to wait for a launch window every 19 months.

[Shane Ross @RossDynamicsLab]

Cycler-palooza: here's all nine Earth-Moon cycler orbit types released together from the Moon's Hill sphere.
Left: rotating frame Right: inertial frame

[Shane Ross @RossDynamicsLab]

Nine families of Earth–Moon cyclers, stable orbits that ferry back and forth between the two, forever. 🌍♾️🌙

In the rotating frame each one closes up and repeats. The label (k₁,k₂) counts the loops: k₁ around the Earth, k₂ around the Moon. Periods run ~42–106 days.

[Shane Ross @RossDynamicsLab]

@a017444 That’s one possibility maybe. One of the benefits of an orbit like this is that, if you spread a bunch of satellites along it, it basically is a shield around the Earth-Moon system, a sort of Golden Dome for Earth’s neighborhood.

[Shane Ross @RossDynamicsLab]

@barrygoldman1 Made by a fellow astrodynamicist, Aaron Rosengren, with UC San Diego. I also appreciate his careful attention to detail

[Shane Ross @RossDynamicsLab]

@Toshiya_A Thank you. 🙏 Orbital mechanics is art

[Shane Ross @RossDynamicsLab]

Let me save you some time there

[Anthony @anthonystaj]

@nytimes this is funny because all the scientists i know get blocked for asking Claude what a mitochondria does

[Jordan Bramble @jordanbramble]

This $161M contract allows us to invest substantial private capital alongside of the @USSpaceForce to rapidly advance the TRL of space nuclear power and propulsion systems.

We will integrate our R1S space reactor design with a spacecraft, complete a ground test, and in addition, power an operational space force ground asset with the Mark-1 demo.

[Shane Ross @RossDynamicsLab]

@PitaGriffin I know what you mean.

All of American history has occurred in just one orbit of Pluto.

[Shane Ross @RossDynamicsLab]

@PitaGriffin A Sun-Earth cycler could look something like this, with a period of ~13 years. There are "interior" and "exterior" cyclers.

This is from the seminal paper of 21st century astrodynamics: https://t.co/JdN8bmGXec

We have some space trash on similar orbits: https://t.co/OS0SKbYJq0

[Shane Ross @RossDynamicsLab]

@PitaGriffin In short, yes. The “tube” structures underlying their construction exist for all mass ratios, so it’s likely stable orbits exist as well. The semi-major axes and eccentricities of the cyclers are a function of the mass ratio.

[Shane Ross @RossDynamicsLab]

@subcivic Here's an example 2-impulse transfer from LEO to a 3D cycler (maybe I haven't mentioned those yet). It rendezvous near the Moon. Total cost 3.7 km/s.

[Shane Ross @RossDynamicsLab]

Earth-Moon cyclers come in a variety of shapes.

Cyclers for different systems depend on the mass ratio of the two large bodies.

Physics preprint: https://t.co/5oQa2IjLgy

[Shane Ross @RossDynamicsLab]

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: https://t.co/v3VDPIT0X4

[Shane Ross @RossDynamicsLab]

@subcivic I’ve looked at the two burn transfers to cyclers and the cheapest ones from LEO enter the cycler near the moon, not at perigee. So you can pick the k1 according to other criteria.

[Latest in space @latestinspace]

25 years ago today, astronaut Frank Culbertson watched the 9/11 attacks unfold from the International Space Station 💔

He was the only American not on Earth

[Shane Ross @RossDynamicsLab]

@SteelCityCoach Maybe you don't like emojis? I've been using them for years. It's funny though. I've put my abstracts going back 25 years into AI detection software and it often thinks it's AI.

[Shane Ross @RossDynamicsLab]

@barrygoldman1 Jupiter is pretty low on the list of perturbations in the Earth's neighborhood. Below Venus. And orders of magnitude under the Sun.

[Shane Ross @RossDynamicsLab]

@subcivic @STvSW I looked at Delta-V and TOF from various cyclers to other periodic orbits, at the same Jacobi constant, which was C =3.1294, different from shown here (if you wanted to compare). We didn't consider legs to and from LEO or LLO, an important missing piece.
https://t.co/rOFP8jAPC8

[Shane Ross @RossDynamicsLab]

When we treat orbits in the Earth-Moon system as a logistics network, these cyclers emerge as the natural depots.

Full video: https://t.co/LPrfxtWUgE
Article: https://t.co/oOz0WGPyQp

[Shane Ross @RossDynamicsLab]

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: https://t.co/v3VDPIT0X4

[Shane Ross @RossDynamicsLab]

@meawoppl @brianweeden This is the idealized circular restricted three-body problem, so Earth and Moon are point masses on a circular orbit about their common center of mass, and the third body is a massless test particle.

[Shane Ross @RossDynamicsLab]

A collection of 9/11 headlines I saved from the time.

When the 9/11 attacks happened, my roommate woke me up to tell me, "Terrorists have destroyed the World Trade Center in New York!". Sounded like a cheesy movie plot. I pointed to the recent photo I took of them and asked, "You mean these?" It didn't seem possible. I was just there...

[Shane Ross @RossDynamicsLab]

Exactly half a lifetime ago I was standing on the South Tower. August 2001. Inset is me, same trip.

[Shane Ross @RossDynamicsLab]

@itoht2 🐠♾️👍🏼

[Shane Ross @RossDynamicsLab]

@SpaceTeapot18 Solution of the CR3BP and full 3-body problem.