orbit_energy Function

public pure function orbit_energy(mu, rv) result(energy)

Compute the two-body orbital energy.

Arguments

Type IntentOptional Attributes Name
real(kind=wp), intent(in) :: mu

gravitational parameter []
real(kind=wp), intent(in), dimension(6) :: rv

position and velocity vector [km,km/s]

Return Value real(kind=wp)

two-body orbital energy []


Source Code

    pure function orbit_energy(mu,rv) result(energy)

    implicit none

    real(wp),intent(in) :: mu               !! gravitational parameter [\(km^{3}/s^{2}\)]
    real(wp),dimension(6),intent(in) :: rv  !! position and velocity vector [km,km/s]
    real(wp) :: energy                      !! two-body orbital energy [\(km^{2}/s^{2}\)]

    real(wp) :: rmag  !! position vector magnitude [km]
    real(wp) :: vmag  !! velocity vector magnitude [km]

    rmag = norm2(rv(1:3))
    vmag = norm2(rv(4:6))

    energy = (vmag**2 / two) - (mu / rmag)

    end function orbit_energy