Mars I
| Phobos Statistics | |
|---|---|
| Discovered by | Asaph Hall |
| Date of discovery | 1877 |
| Mass (kg) | 1.08e+16 |
| Mass (Earth = 1) | 1.8072e-09 |
| Radius (km) | 13.5x10.8x9.4 |
| Radius (Earth = 1) | 2.1167e-03 |
| Mean density (gm/cm^3) | 2.0 |
| Mean distance from Mars (km) | 9,380 |
| Rotational period (days) | 0.31910 |
| Orbital period (days) | 0.31910 |
| Mean orbital velocity (km/sec) | 2.14 |
| Orbital eccentricity | 0.01 |
| Orbital inclination (degrees) | 1.0 |
| Escape velocity (km/sec) | 0.0103 |
| Visual geometric albedo | 0.06 |
| Magnitude (Vo) | 11.3 |