g=3.728  omega=7.0882e-05  corotation=20,428 km  surface spin speed=240 m/s
h_km | r0/rc | flight min | east km | impact m/s | angle from horizontal | equiv launch m/s | energy MJ/kg
   500 | 0.19 |    9.7 |      13 |   1797 | 87.6 |   1797 | 1.62
 1,000 | 0.21 |   15.3 |      41 |   2391 | 86.1 |   2391 | 2.86
 2,000 | 0.26 |   25.9 |     131 |   3048 | 83.1 |   3048 | 4.65
 3,000 | 0.31 |   37.1 |     268 |   3423 | 79.7 |   3423 | 5.86
 4,000 | 0.36 |   49.3 |     456 |   3669 | 75.8 |   3669 | 6.73
 6,000 | 0.46 |   77.4 |   1,011 |   3970 | 66.2 |   3970 | 7.88
 8,000 | 0.56 |  112.8 |   1,903 |   4142 | 53.4 |   4142 | 8.58
10,000 | 0.66 |  161.7 |   3,525 |   4246 | 34.3 |   4246 | 9.02
11,000 | 0.70 |  197.7 |   5,318 |   4282 | 17.2 |   4282 | 9.17
fall-back threshold: release below r=14,722 km from centre (h=11,332 km), = 0.72 of corotation
east offset reaches 600 km at h≈ 4600 km
t=   0.25 h  conductive crust ~ 0.06 m
t=      1 h  conductive crust ~ 0.12 m
t=      3 h  conductive crust ~ 0.21 m
t=     24 h  conductive crust ~ 0.59 m
t=    720 h  conductive crust ~ 3.22 m
t=   8760 h  conductive crust ~ 11.23 m
deposit thickness 1 km: volume 1,188,229 km3 = 208 x Phobos; equivalent sphere diameter 131 km
   eta=1e+02 Pa s -> time to spread to 615 km radius: 2.73e-08 yr
   eta=1e+04 Pa s -> time to spread to 615 km radius: 2.73e-06 yr
   eta=1e+06 Pa s -> time to spread to 615 km radius: 0.000273 yr
   eta=1e+08 Pa s -> time to spread to 615 km radius: 0.0273 yr
   eta=1e+10 Pa s -> time to spread to 615 km radius: 2.73 yr
   eta=1e+12 Pa s -> time to spread to 615 km radius: 273 yr
deposit thickness 3 km: volume 3,564,687 km3 = 625 x Phobos; equivalent sphere diameter 190 km
   eta=1e+02 Pa s -> time to spread to 615 km radius: 1.01e-09 yr
   eta=1e+04 Pa s -> time to spread to 615 km radius: 1.01e-07 yr
   eta=1e+06 Pa s -> time to spread to 615 km radius: 1.01e-05 yr
   eta=1e+08 Pa s -> time to spread to 615 km radius: 0.00101 yr
   eta=1e+10 Pa s -> time to spread to 615 km radius: 0.101 yr
   eta=1e+12 Pa s -> time to spread to 615 km radius: 10.1 yr
deposit thickness 7 km: volume 8,317,602 km3 = 1,459 x Phobos; equivalent sphere diameter 251 km
   eta=1e+02 Pa s -> time to spread to 615 km radius: 7.95e-11 yr
   eta=1e+04 Pa s -> time to spread to 615 km radius: 7.95e-09 yr
   eta=1e+06 Pa s -> time to spread to 615 km radius: 7.95e-07 yr
   eta=1e+08 Pa s -> time to spread to 615 km radius: 7.95e-05 yr
   eta=1e+10 Pa s -> time to spread to 615 km radius: 0.00795 yr
   eta=1e+12 Pa s -> time to spread to 615 km radius: 0.795 yr
