Start game with space bar

My project is almost complete except for this last little thing that's been bugging me. A tutorial I followed had you start the game by clicking a button but I would like to change that to pressing the spacebar starts the game. I tried:

if(Key.isDown)(Key.SPACE))

{

     _root.ship.newGame();

}

But nothing happens when I press the spacebar.

Here's the starting code with the button for my file Ship.as

function onLoad()

{

     _visible = false;

     _root.winMenu._visible = false;

     _root.gameOverMenu._visible = false;

     _root.healthMeter._visible = false;

     _root.enemyHealthMeter._visible = false;

     _root.playMenu.playButton.onPress = function()

     {

          _root.ship.newGame();

     }

}

function newGame()

{

//code for the main game screen

}