Mars¶
Mars is a terrestrial planet with a thin CO₂ atmosphere, extreme diurnal and seasonal temperature swings, a low-pressure surface environment, and extensive polar CO₂ and water ice deposits. It is the primary target of the tform simulator.
Physical constants¶
All values from the NASA Mars Fact Sheet:
| Property | Symbol | Value | Unit |
|---|---|---|---|
| Mass | \(M\) | \(6.4171 \times 10^{23}\) | kg |
| Mean radius | \(R\) | \(3\,389\,500\) | m |
| Surface gravity | \(g\) | \(3.721\) | m s⁻² |
| Sidereal rotation period | — | \(88\,642.66\) | s (~24h 37m) |
| Orbital period | — | \(686.97\) | Earth days |
| Semi-major axis | \(a\) | \(1.524\) | AU |
| Orbital eccentricity | \(e\) | \(0.0934\) | — |
| Axial tilt | \(\varepsilon\) | \(25.19°\) | — |
Current atmospheric state¶
Mars today has a surface pressure of approximately \(636\,\text{Pa}\) — less than 1% of Earth's \(101\,325\,\text{Pa}\). The atmosphere is \(\sim 95\%\) CO₂ with trace N₂, Ar, and O₂ (Mahaffy et al., 2013):
| Species | Volume mixing ratio |
|---|---|
| CO₂ | 95.32% |
| N₂ | 2.60% |
| Ar | 1.93% |
| O₂ | 0.13% |
| CO | 0.08% |
Mean surface temperature is approximately \(210\,\text{K}\) (\(-63°\text{C}\)), with diurnal swings of 60–100 K and seasonal swings driven by CO₂ cap cycling.
The implementation uses MARS_ROTATION_PERIOD = 88775.244 s as its model sol
and MARS_ORBITAL_PERIOD = 59356800 s (about 668.62 model sols). These differ
from the sidereal rotation value in the fact-sheet table; use the model constants
when reproducing its clock and timestep settings.
Mars in tform¶
The 3-D GCM is the primary model. It evolves spatial circulation, atmospheric/surface temperature, pressure and frost over MOLA terrain. Start with GCM setup and read validation limits. The torch global-mean model and its injection workflows are deprecated.
| Topic | Page |
|---|---|
| Solar flux and zenith angle model | Solar Flux |
| Spatial dynamics and column physics | Climate Model |
| Deprecated global-mean GHG injection | GHG Interventions |
| API reference | Mars API |
| Architecture | Mars Architecture |