{
  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "---\n",
        "title: \"Moon Cannon: dos\"\n",
        "description: |\n",
        "  Can you shoot Earth from the Moon? Simulate lunar ballistic launches with Julia. Explore orbital mechanics, gravity, and drag in a simplified Moon-to-Earth cannon model.\n",
        "date: 2024-09-25\n",
        "categories:\n",
        "  - Julia\n",
        "  - Astrodynamics\n",
        "  - Code\n",
        "  - Aerospace\n",
        "  - Space\n",
        "  - Math\n",
        "draft: false\n",
        "freeze: false\n",
        "image: moon_spirograph.png\n",
        "---"
      ],
      "id": "e623b02d"
    },
    {
      "cell_type": "code",
      "metadata": {},
      "source": [
        "using SPICE\n",
        "\n",
        "const LSK = \"https://naif.jpl.nasa.gov/pub/naif/generic_kernels/lsk/naif0012.tls\"\n",
        "const SPK = \"https://naif.jpl.nasa.gov/pub/naif/generic_kernels/spk/planets/de440.bsp\"\n",
        "\n",
        "# Download kernels\n",
        "download(LSK, \"naif0012.tls\")\n",
        "download(SPK, \"de440.bsp\")\n",
        "\n",
        "# Load leap seconds kernel\n",
        "furnsh(\"naif0012.tls\")\n",
        "\n",
        "# Load a planetary ephemeris kernel\n",
        "furnsh(\"de440.bsp\")\n",
        "\n",
        "function get_planet_positions(epoch)\n",
        "    planets = [\"MERCURY\", \"VENUS\", \"EARTH\", \"MARS\", \n",
        "               \"JUPITER\", \"SATURN\", \"URANUS\", \"NEPTUNE\"]\n",
        "    positions = Dict()\n",
        "\n",
        "    for planet in planets\n",
        "        # Get position vector in km relative to Sun\n",
        "        pos, _ = spkpos(planet, epoch, \"J2000\", \"NONE\", \"earth\")\n",
        "        positions[planet] = pos\n",
        "    end\n",
        "\n",
        "    return positions\n",
        "end\n",
        "\n",
        "# Example usage (epoch in UTC)\n",
        "epoch = \"1995-12-17T12:00:00\" |> utc2et\n",
        "positions = get_planet_positions(epoch)"
      ],
      "id": "72207da4",
      "execution_count": null,
      "outputs": []
    }
  ],
  "metadata": {
    "kernelspec": {
      "name": "julia-1.11",
      "language": "julia",
      "display_name": "Julia 1.11.1",
      "path": "/root/.local/share/jupyter/kernels/julia-1.11"
    }
  },
  "nbformat": 4,
  "nbformat_minor": 5
}