# Project Structure
Structure map for the Phoboss crate.
```text
Phoboss/
├── README.md # Project overview and usage
├── LICENSE # MIT license
├── ChangeLog.md # Version history
├── ComingSoon.md # Planned features
├── Contributing # Contribution guidelines
├── lastest_versions.sh # Restore wildcard dependency versions
│
├── src/
│ ├── main.rs # Entry point — Phobos diagnostics: orbit, Stickney crater, tidal decay
│ ├── lib.rs # Library root, PHOBOSMASS (1.07e16 kg), mean radius 11.3 km, constants
│ │
│ ├── environment/ # Surface environment
│ │ ├── mod.rs # Exports dust, radiation, thermal
│ │ ├── dust.rs # Regolith dust layer, electrostatic mobilization on low-gravity body
│ │ ├── radiation.rs # Unshielded solar + GCR exposure at 1.52 AU, Mars shadow partial shield
│ │ └── thermal.rs # Surface ~233 K (day) / ~160 K (night), rapid thermal cycling (7.66 h)
│ │
│ ├── exosphere/ # Tenuous atmosphere
│ │ ├── mod.rs # Exports charging, escape, species
│ │ ├── charging.rs # Solar-wind charging, Mars magnetotail passage effects
│ │ ├── escape.rs # Near-zero escape velocity (~11 m/s), dust easily lofted
│ │ └── species.rs # No measurable exosphere, possible transient outgassing from impacts
│ │
│ ├── geodata/ # Geographic reference data
│ │ ├── mod.rs # Exports coordinates, elevation, landing_sites, regions
│ │ ├── coordinates.rs # Body-fixed frame, IAU Phobos-fixed reference, triaxial shape
│ │ ├── elevation.rs # Shape model from Viking/MRO/MEX imagery, Stickney depression
│ │ ├── landing_sites.rs # MMX sample-return touchdown sites, smooth regolith plains
│ │ └── regions.rs # Stickney crater (9 km), grooved terrain, Limtoc/Reldresal craters
│ │
│ ├── geology/ # Surface and interior geology
│ │ ├── mod.rs # Exports craters, erosion, mountains, regolith, volcanism
│ │ ├── craters.rs # Stickney (9 km, nearly catastrophic), Hall (5 km), groove-associated pits
│ │ ├── erosion.rs # Impact gardening, regolith migration in low gravity
│ │ ├── mountains.rs # Stickney rim peaks, irregular shape ridges, no significant mountains
│ │ ├── regolith.rs # ~100 m regolith layer, fine-grained, blanketing grooves
│ │ └── volcanism.rs # No volcanism — undifferentiated interior, possible rubble pile
│ │
│ ├── interactions/ # Gravitational interactions
│ │ ├── mod.rs # Exports earth_tides, marss, orbital_dynamics
│ │ ├── earth_tides.rs # Earth–Phobos perturbation (negligible at 1.52 AU)
│ │ ├── marss.rs # Mars gravitational influence, tidally decaying orbit at 6 000 km altitude
│ │ └── orbital_dynamics.rs # Spiraling inward, Roche limit breakup in ~50 Myr, tidal deceleration
│ │
│ ├── lighting/ # Illumination model
│ │ ├── mod.rs # Exports eclipses, marsshine, solar_position
│ │ ├── eclipses.rs # Frequent Mars shadow transits (~1 300/yr), annular eclipses from Mars
│ │ ├── marsshine.rs # Reflected Martian light, reddish illumination, Mars fills ~42° of sky
│ │ └── solar_position.rs # Solar zenith angle, 7.66 h rapid rotation/orbital cycle
│ │
│ ├── missions/ # Exploration missions
│ │ ├── mod.rs # Exports landers, orbiters, relay
│ │ ├── landers.rs # MMX sample return (JAXA), Phobos-Grunt (failed), future ISRU scouts
│ │ ├── orbiters.rs # Viking imaging, Phobos 2 flyby, Mars Express close flybys (<100 km)
│ │ └── relay.rs # Mars relay network, low-altitude orbit advantageous for surface ops
│ │
│ ├── observation/ # Remote observation
│ │ ├── mod.rs # Exports communications, mars_view, navigation
│ │ ├── communications.rs # Mars-relay link, 1.52 AU Earth light-time delay (3–22 min)
│ │ ├── mars_view.rs # Mars apparent size from Phobos (~42°), enormous disk dominates sky
│ │ └── navigation.rs # Irregular gravity field, MEGANE gamma-ray spectrometer mapping
│ │
│ ├── physics/ # Orbital and impact mechanics
│ │ ├── mod.rs # Exports collisions, orbit, rotation, tides
│ │ ├── collisions.rs # Impact flux at 1.52 AU, secondary ejecta from Mars impacts
│ │ ├── orbit.rs # a = 9 376 km, e = 0.0151, period 0.32 d (7.66 h), vis-viva
│ │ ├── rotation.rs # Synchronous rotation, orbits faster than Mars rotates (rises in west)
│ │ └── tides.rs # Tidal deceleration, approaching Roche limit, structural stress
│ │
│ ├── rendering/ # Visual rendering pipeline
│ │ ├── mod.rs # Exports dust, materials, shaders
│ │ ├── dust.rs # Regolith dust rendering, very dark surface albedo (0.07)
│ │ ├── lod.rs # Pixel-precise adaptive LOD
│ │ ├── materials.rs # PBR dark C/D-type material, phyllosilicate/carbon spectral match
│ │ ├── mesh.rs # Icosphere subdivision, vertex data
│ │ └── shaders.rs # GPU shader programs — Stickney crater, groove system rendering
│ │
│ ├── resources/ # Extractable resources
│ │ ├── mod.rs # Exports minerals, regolith, water_ice
│ │ ├── minerals.rs # Phyllosilicates, carbon-bearing minerals, possible chondritic composition
│ │ ├── regolith.rs # Thick fine-grained regolith — ISRU feedstock, radiation shielding
│ │ └── water_ice.rs # Possible bound water in hydrated minerals, MMX will constrain
│ │
│ ├── surface/ # Surface mapping
│ │ ├── mod.rs # Exports heightmaps, mapping, zones
│ │ ├── heightmaps.rs # Shape model 27 × 22 × 18 km triaxial from MEX/MRO
│ │ ├── mapping.rs # Albedo maps, groove maps, spectral unit mapping (red/blue units)
│ │ └── zones.rs # Stickney region, grooved terrain, smooth regolith plains
│ │
│ ├── temporal/ # Time systems
│ │ ├── mod.rs # Exports calendar, epoch, time_scale
│ │ ├── calendar.rs # Phobos calendar — 7.66 h orbital period, Mars year reference
│ │ ├── epoch.rs # J2000 epoch, Viking encounter dates, MMX mission timeline
│ │ └── time_scale.rs # TDB/UT1/TAI conversions at 1.52 AU light-time delay
│ │
│ └── terrain/ # Terrain mesh generation
│ ├── mod.rs # Exports lod, mesh, texturing
│ ├── lod.rs # Level-of-detail streaming for irregular body and groove detail
│ ├── mesh.rs # Triaxial mesh, 27 × 22 × 18 km, Stickney concavity
│ └── texturing.rs # Viking/MRO/MEX imagery drape, dark surface with red/blue spectral units
│
├── tests/ # Integration tests
│ ├── environment_tests.rs # Tests rapid thermal cycling, dust mobilization, radiation dose
│ ├── exosphere_tests.rs # Tests near-zero exosphere, dust lofting escape threshold
│ ├── geodata_tests.rs # Tests coordinate transforms, Stickney location, groove positions
│ ├── geology_tests.rs # Tests Stickney formation energy, groove origin models, regolith depth
│ ├── interactions_tests.rs # Tests tidal decay rate, Roche limit timeline (~50 Myr)
│ ├── lighting_tests.rs # Tests Mars shadow transit frequency, marsshine from 42° disk
│ ├── missions_tests.rs # Tests Mars Express flyby parameters, MMX trajectory
│ ├── observation_tests.rs # Tests Mars apparent size (42°), relay link budget
│ ├── physics_tests.rs # Tests orbital period (7.66 h), tidal stress, escape velocity
│ ├── rendering_tests.rs # Tests surface albedo (0.07), spectral unit contrast
│ ├── resources_tests.rs # Tests phyllosilicate fraction, bound water estimates
│ ├── surface_tests.rs # Tests shape model accuracy, groove pattern mapping
│ ├── temporal_tests.rs # Tests epoch conversions, rapid orbital period sync
│ └── terrain_tests.rs # Tests irregular mesh accuracy, Stickney rim LOD
│
└── examples/ # Runnable examples
├── check_landing_site.rs # Evaluate MMX touchdown candidates on smooth regolith
├── crater_sim.rs # Stickney near-catastrophic impact, groove formation models
├── eclipse_sim.rs # Frequent Mars shadow transits, annular solar eclipses
├── exosphere_sim.rs # Dust lofting simulation in near-zero gravity
├── mars_observation.rs # Mars as seen from Phobos — enormous 42° reddish disk
├── orbital_sim.rs # 7.66-hour orbit propagation, tidal inspiral toward Roche limit
├── radiation_sim.rs # Solar + GCR environment, intermittent Mars shadow shielding
├── resource_survey.rs # Phyllosilicate and bound water abundance mapping
└── tidal_effects.rs # Tidal decay analysis — orbital inspiral and breakup timeline
```