g = 9.80665                     # local gravitational acceleration in [m/s^2]
c_v = 3115.89                   # [J/(kg * K)]  specific heat Helium
R_air = 287.1                   # Specific Gas Constant Dry Air in [J/(kg * K)]
R_gas = 2077.1                  # Specific Gas Constant Helium in [J/(kg * K)]
R_E = 6378000                   # Earth Radius in [m]
e = 0.016708                    # Eccentricity of Earth's Orbit
sigma = 5.670374419 * 10 ** -8  # Stefan-Boltzmann-Constant
gamma = 1.667                   # 1.44 # 1.6
# p_0 = 101325                    # sea-level pressure in [Pa]