{
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  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "application/javascript": [
       "if (typeof Jupyter !== \"undefined\") {require.undef(\"nbextensions/vpython_libraries/glow.min\");}else{element.textContent = ' ';}"
      ],
      "text/plain": [
       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "application/javascript": [
       "if (typeof Jupyter !== \"undefined\") {require.undef(\"nbextensions/vpython_libraries/glowcomm\");}else{element.textContent = ' ';}"
      ],
      "text/plain": [
       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "application/javascript": [
       "if (typeof Jupyter !== \"undefined\") {require.undef(\"nbextensions/vpython_libraries/jquery-ui.custom.min\");}else{element.textContent = ' ';}"
      ],
      "text/plain": [
       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "application/javascript": [
       "if (typeof Jupyter !== \"undefined\") {require([\"nbextensions/vpython_libraries/glow.min\"], function(){console.log(\"GLOW LOADED\");});}else{element.textContent = ' ';}"
      ],
      "text/plain": [
       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "application/javascript": [
       "if (typeof Jupyter !== \"undefined\") {require([\"nbextensions/vpython_libraries/glowcomm\"], function(){console.log(\"GLOWCOMM LOADED\");});}else{element.textContent = ' ';}"
      ],
      "text/plain": [
       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "application/javascript": [
       "if (typeof Jupyter !== \"undefined\") {require([\"nbextensions/vpython_libraries/jquery-ui.custom.min\"], function(){console.log(\"JQUERY LOADED\");});}else{element.textContent = ' ';}"
      ],
      "text/plain": [
       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "text/html": [
       "<div id=\"glowscript\" class=\"glowscript\"></div>"
      ],
      "text/plain": [
       "<IPython.core.display.HTML object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "application/javascript": [
       "if (typeof Jupyter !== \"undefined\") { window.__context = { glowscript_container: $(\"#glowscript\").removeAttr(\"id\")};}else{ element.textContent = ' ';}"
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       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
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    }
   ],
   "source": [
    "from vpython import *\n",
    "scene.width =1024\n",
    "scene.height = 760"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "CONSTANTS AND OBJECTS"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "#CONSTANTS\n",
    "G = 6.7e-11\n",
    "mEarth = 6e24\n",
    "mcraft = 15e3\n",
    "deltat = 60\n",
    "\n",
    "#OBJECTS\n",
    "Earth = sphere(pos=vector(0,0,0), radius=6.4e6, color=color.cyan)\n",
    "craft = sphere(pos=vector(-10*Earth.radius, 0,0), color=color.yellow, make_trail=True)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "#INITIAL VALUES\n",
    "vcraft = vector(0,0,0)\n",
    "\n",
    "t = 0\n",
    "scene.autoscale = 0       ## do not allow camera to zoom in or out\n",
    "\n",
    "#CALCULATIONS\n",
    "\n",
    "while t < 10*365*24*60*60:\n",
    "    rate(200)       ## make animation display\n",
    "    ## you must add statements for the iterative update of \n",
    "    ## gravitational force, velocity, and position\n",
    "\n",
    "\n",
    "    ## check to see if the spacecraft has crashed on the Earth.\n",
    "    ## if so, get out of the calculation loop\n",
    "    \n",
    "    t = t+deltat\n",
    "\n",
    "print('Calculations finished after ',t,'seconds')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
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