d(t) = (0.0001).t³
Pour la troposphère d(t) = 15 km
15 = (0.0001).t³
15/0.0001 = t³
150 000 = t³ et t = ∛150000 = 53.13 secondes = 58 s
Pour la thermosphere d(t) = 400 km
400 = (0.0001).t³
400/0.0001 = t³
400 000 = t³ et t = ∛400000 = 158.74 secondes = 159 s