Genova/Aldrin free-return Earth-Moon cycler (interplanetary cruise ship, 3:1 lunar resonant)

genova-aldrin-2015-em-3petal-cycler · source: literature · validation: V0

Signature

Bodies: E-Moon
Sequence (canonical): E-Moon
Sense: n/a
Period: — yr ( × E-Moon synodic)
The paper describes a circumlunar periodic orbit with Earth encounters every 7 or 10 days and lunar encounters every 26 days. The 26-day Moon-encounter cadence corresponds to one lunar sidereal period (27.3 d) modulo phasing; the cycler is qualitatively a 3-petal (3:1) lunar resonant trajectory in the Earth-Moon rotating frame. The single "period" of the cycler as a whole is not isolated in the accessible abstract — left null with the cadence captured below as legs/encounters.
Priority date: 2015-08-09

V∞ at encounters

E (#1): — (not published)
Not tabulated in accessible material (NTRS abstract + Semantic Scholar landing page; full PDF inaccessible to this ingest). Per spec §16.1 honesty rule, left null with the gap noted rather than guessed.
Moon (#2): — (not published)
Same — not in the accessible abstract.

Orbit elements (heliocentric)

Semi-major axis a: — AU
Eccentricity e: —
Perihelion: — AU
Aphelion: — AU
Inclination: —°

Geocentric (not heliocentric) orbital elements would apply here. Not tabulated in the accessible abstract.

Legs

E → E: 7 d, null revs
Earth-to-Earth encounter cadence: "close-Earth encounters every 7 or 10 days" per the NTRS abstract. The 7 / 10 d alternation is a feature of the 3-petal geometry with solar-gravity phasing.
E → Moon: 26 d, null revs
Earth-Moon encounter cadence: "Lunar encounters occur every 26 days" per the NTRS abstract.

Primary citation

Genova, A. L. & Aldrin, B. (2015). A Free-Return Earth-Moon Cycler Orbit for an Interplanetary Cruise Ship. AAS/AIAA Astrodynamics Specialist Conference, Vail CO, August 9-13, 2015.

URL: https://ntrs.nasa.gov/citations/20150018049

NASA report number ARC-E-DAA-TN22765 per the NTRS metadata. The specific AAS paper number (e.g. AAS 15-XXX) is not exposed in the NTRS record; the citation here uses the conference venue only. AIAA-hosted PDFs returned HTTP 403 to ingest, so the abstract content cited below comes from the NTRS landing page.

Corroborating sources

Genova, A. L. (2016). Circumlunar Free-Return Cycler Orbits for a Manned Earth-Moon Space Station. NTRS 20160004674. · link
Companion / follow-up report from the same author covering the same orbit family.

Notes

Buzz Aldrin's lunar-cycler extension of his Earth-Mars cycler concept. Co-authored with NASA Ames trajectory analyst Anthony L. Genova. The orbit is "free-return" in the sense that any spacecraft flying on it will naturally return to Earth without propulsion; "modest phasing maneuvers" (average 39 m/s per month per the abstract) compensate for solar-gravity perturbations and keep the geometry repeating. Useful as a destination for crew transfer: per the abstract, lunar encounters "offer the chance for a smaller craft to depart the cycler and enter lunar orbit, or head for a Lagrange point (e.g., EM-L2 halo orbit), distant retrograde orbit (DRO), or interplanetary destination such as a near-Earth object (NEO) or Mars." MODEL NOTE: like the Arenstorf entry, this is best modelled in the Earth-Moon CR3BP with solar-perturbation third-body, not in patched-conic + V_infinity. The numerical signature fields are largely null and should not be used for M7 novelty matching against heliocentric finder hits.

Source quotes (per-field provenance)

Every numerical value in this entry traces to a verbatim or paraphrased quote from a cited source.

first_published.title: NTRS 20150018049 title: "A Free-Return Earth-Moon Cycler Orbit for an Interplanetary Cruise Ship" — Genova, Aldrin.
legs[0].tof_days: NTRS abstract: "introducing solar gravity and modest phasing maneuvers (average of 39 m/s per month) which yields close-Earth encounters every 7 or 10 days."
legs[1].tof_days: NTRS abstract: "Lunar encounters occur every 26 days and offer the chance for a smaller craft to depart the cycler and enter lunar orbit..."
notes: NTRS abstract: "introducing solar gravity and modest phasing maneuvers (average of 39 m/s per month)" (delta-V budget cited in notes).