Why would North Korea test fire its missiles?

North Korea appears to have made further preparations to test its longest-range Taepodong-2 missile as well as short-range missiles.

Here are questions and answers as to why North Korea might test launch one of its missiles:

WHAT DOES THE NORTH STAND TO GAIN THROUGH TESTING ITS

LONGEST-RANGE MISSILE?

If the launch is successful, North Korea will have a missile with a maximum estimated range of 6,700 km (4,200 miles), designed to carry a nuclear warhead that could hit U.S. territory, although not the continental 48 states. This would, for the first time, pose a direct security threat by the North to the United States.

The North, which already has hundreds of rudimentary missiles, would be able to test its multi-stage rocket systems and increase its ability to produce long-range missiles.

HOW BIG A THREAT IS THE TAEPODONG-2?

The only time North Korea has fired the missile was in 2006 when it managed just a few seconds of controlled flight and broke apart in less than a minute