# Jacchia-Roberts 1971 Atmospheric model is now available in SatelliteToolbox.jl

**URL:** <https://discourse.julialang.org/t/jacchia-roberts-1971-atmospheric-model-is-now-available-in-satellitetoolbox-jl/16758>\
**Category:** Astro/Space\
**Created:** [October 24, 2018, 8:06pm UTC](https://discourse.julialang.org/t/jacchia-roberts-1971-atmospheric-model-is-now-available-in-satellitetoolbox-jl/16758 "2018-10-24T20:06:36Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Ronis\_BR](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ronis_br/32/50999_2.png) [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)\
**Post date:** [October 24, 2018, 8:06pm UTC](https://discourse.julialang.org/t/jacchia-roberts-1971-atmospheric-model-is-now-available-in-satellitetoolbox-jl/16758/1 "2018-10-24T20:06:36Z")

</div>

Hi guys!

I just want to let you know that we now have a native implementation of The Jacchia-Roberts 1971 atmospheric model in [SatelliteToolbox.jl](https://github.com/JuliaSpace/SatelliteToolbox.jl). You just need to use `master` because I still need to do somethings before tagging a new version.

This model is supposed to be less accurate than Jacchia-Bowman 2008 and NRLMSISE-00. However, the computational burden is much lower (10x less than NRLMSISE-00 and something like 70x less than JB2008).

I managed to obtain some data from GMAT, but the tests are very limited. I will appreciate if anyone can help me to validate the implementation!

```julia
julia> jr1971(DatetoJD(2017,1,1,0,0,0), 45*pi/180, 0*pi/180, 300e3, 76.5, 72.5, 7)
JR1971_Output{Float64}
  nN2: Float64 4.0269432130021164e13
  nO2: Float64 1.8040704522884658e12
  nO: Float64 4.976154354226309e14
  nAr: Float64 4.914191344437922e9
  nHe: Float64 1.0731503643725797e13
  nH: Float64 0.0
  rho: Float64 1.526144428631946e-11
  T_exo: Float64 871.4209785497403
  Tz: Float64 858.5927825073542

```

The documentation is:

```julia-repl
  function jr1971(JD::Number, glat::Number, glon::Number, h::Number, F10::Number,

  Compute the atmospheric density using the Jacchia-Roberts 1971 model.

  Args
  ≡≡≡≡≡≡

    • JD: Julian day.

    • glat: Geodetic latitude [rad].

    • glon: Geodetic longitude [rad].

    • h: Altitude [m].

    • F10: 10.7-cm solar flux [10⁻²² W/(M² Hz)].

    • F10ₐ: 10.7-cm averaged solar flux, 81-day centered on input time.

    • Kp: Kp geomagnetic index (with a delay of 3 hours).

  Returns
  ≡≡≡≡≡≡≡≡≡

  An instance of the structure JR1971_Output with the computed values.

```