Siding Spring
A long-period comet that made an exceptionally close pass of Mars in October 2014, observed up close by the fleet of Mars orbiters and rovers.
Imagery
Mars Curiosity Rover Views Comet Siding Spring
This image from an animiation of comet C/2013 A1 Siding Spring were taken by the Mast Camera Mastcam on NASA Curiosity Mars rover as the comet passed near the red planet on Oct.
2014
NASA/JPL-Caltech/MSSS/TAMU · NASA media (public domain)
Orbit & physical parameters
Osculating orbit and physical parameters from the NASA JPL Small-Body Database · Hyperbolic Comet · epoch 2016-04-02 (JD 2457480.5 TDB) · Earth MOID 0.383565 au
| Semi-major axis | -16,366 ± 547.3 au | NASA JPL · calculated |
| Eccentricity | 1.000086 ± 2.8601e-6 | NASA JPL · calculated |
| Perihelion distance | 1.399765 ± 1.2332e-6 au | NASA JPL · calculated |
| Inclination | 129.032918 ± 2.0974e-5 deg | NASA JPL · calculated |
| Longitude of ascending node | 300.99941 ± 0.000118 deg | NASA JPL · calculated |
| Argument of perihelion | 2.449169 ± 7.3405e-5 deg | NASA JPL · calculated |
Full field-level provenance
- Semi-major axis: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · a · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Davide Farnocchia, 449 obs · retrieved 2026-07-11
- Eccentricity: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · e · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Davide Farnocchia, 449 obs · retrieved 2026-07-11
- Perihelion distance: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · q · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Davide Farnocchia, 449 obs · retrieved 2026-07-11
- Inclination: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · i · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Davide Farnocchia, 449 obs · retrieved 2026-07-11
- Longitude of ascending node: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · om · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Davide Farnocchia, 449 obs · retrieved 2026-07-11
- Argument of perihelion: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · w · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Davide Farnocchia, 449 obs · retrieved 2026-07-11
Orbital elements are a calculated JPL orbit-determination fit, all referred to the single osculating epoch above (solution by Davide Farnocchia); each carries its own uncertainty. This is an unbound (hyperbolic) orbit: eccentricity ≥ 1, a negative semi-major axis and no aphelion. Fields the database did not provide are omitted, never invented.
Classification & origin
Knowledge connections
- Member of groupLong-Period Comets
- Source reservoirOort Cloud
- Associated withMars
Sources
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.
- NASA JPLJet Propulsion Laboratory / Solar System Dynamics
Orbital data, ephemerides, and small-body parameters for planets, asteroids, and comets.