Niehoff VISIT-2 Earth-Mars cycler

niehoff-visit2 · source: literature · validation: V0

Signature

Bodies: E-M
Sequence (canonical): E-M
Sense: n/a
Period: 14.950 yr (7 × E-M synodic)
REVIEW FIX (2026-05-31): similar arithmetic-check to VISIT-1. The a = 1.31 AU element gives heliocentric orbital period P = 1.31^1.5 ≈ 1.50 yr → 2 orbits in 3 yr (matches Earth encounters) and 5 orbits in 7.5 yr (4 Mars years = 4 × 1.88 = 7.52, matches Mars encounters). The "7 synodic periods" / 14.95 yr framing from Rogers 2012 footnote 'a' is consistent with these elements; the apparent inconsistency in earlier-noted secondary sources resolves cleanly once the orbital period is computed from (a, e).
Priority date: 1985-07-01

V∞ at encounters

E (#1): — (not published)
Same gap as VISIT-1 — V_inf for the cycler itself not directly tabulated in accessible sources.
M (#2): — (not published)
Same gap.

Orbit elements (heliocentric)

Semi-major axis a: 1.310 AU
Eccentricity e: 0.275
Perihelion: 0.950 AU
Aphelion: 1.670 AU
Inclination: 0.00°

Rogers et al. 2012 Table 1. NB aphelion 1.67 AU is ~Mars's aphelion in the real ephemeris; this VISIT-2 orbit only intersects Mars's orbit when Mars is near aphelion.

Primary citation

Niehoff, J. (1985). Manned Mars Mission Design. Joint AIAA/Planetary Society Conference 'Steps to Mars', National Academy of Sciences.

Corroborating sources

Niehoff, J. (1986). Pathways to Mars: New Trajectory Opportunities. AAS Paper 86-172.
Friedlander, A. L. et al. (1986). Circulating Transportation Orbits Between Earth and Mars. AIAA 86-2009-CP. DOI: 10.2514/6.1986-2009

Notes

Per spaceflighthistory.blogspot (summarising Niehoff 1985): "A VISIT-2 orbit would need 1.5 Earth years to complete, with a spacecraft encountering Earth twice in three Earth years and Mars five times in four Mars years." Rogers 2012's (a, e, peri, apo) numbers imply orbital period P = 2pi*sqrt(a^3/mu_sun) ≈ 1.50 yr, consistent. Same source-mismatch caveats as VISIT-1 apply.

Source quotes (per-field provenance)

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

a_au: Rogers et al. 2012 Table 1: 'VISIT-2 ... Semi-Major Axis, AU: 1.31'.
e: Rogers et al. 2012 Table 1: 'VISIT-2 ... Eccentricity: 0.275'.
perihelion_au: Rogers et al. 2012 Table 1: 'VISIT-2 ... Perihelion Radius, AU: 0.95'.
aphelion_au: Rogers et al. 2012 Table 1: 'VISIT-2 ... Aphelion Radius, AU: 1.67'.
period.years: Rogers 2012 Table 1 footnote a: 7 synodic periods = 14.95 yr.