By Rob Watson
Defence and security correspondent, BBC News
Like most things about North Korea, little is known for certain about the Taepodong 2 missile.
But there is no doubt North Korea does have a very long standing and pretty sophisticated missile programme.
North Korea's intentions are under the global spotlight
In 1998, before it began observing a moratorium on tests, North Korea launched a Taepodong 1 missile which passed over northern Japan and surprised Western intelligence agencies by the use of three stages in the missile's propulsion system.
What is striking about the Taepodong 2 is that it could well be North Korea's first genuine intercontinental ballistic missile (ICBM) - a missile with a range of more than 5,500km (3,400 miles).
Just how far it might be able to travel and with what weight and type of warhead and level of accuracy is uncertain.
But it has been suggested it could have a range up to 15,000km.
That would put Alaska or Hawaii within its reach and even the continental US if a lighter warhead were used.
In a sense though, what is more important here than the missile's precise specifications is what it says about North Korea's strategic intentions.
It indicates Pyongyang's apparent desire to have weapons of mass destruction and the means to deliver them at great distance.
North Korea's thinking appears to be that if it has nuclear weapons, which it claims to have, and the means to deliver them it should be safe from an attack by the US - a line of reasoning no doubt strengthened by the fate suffered by Iraq.
Just as worrying as North Korea's strategic goals are the dangers of proliferation should Pyongyang master a workable ICBM.
In the past, the North Koreans have shared their technology with Pakistan and Iran and other nations and may well do so again.
So what can the US do militarily about any missile test by Pyongyang?
The US has already moved a couple of naval ships off the coast of North Korea to detect and track the launch of any missile.
It is also likely that the US has activated its still unproven and limited anti-missile defence system.
The system, which is based on linking radar and satellite information to nine interceptor missiles based in Alaska and California, has so far failed to intercept a single missile in recent tests.
For now though, the US appears to be relying more on the hope that North Korea is bluffing and that pressure from South Korea, Japan and China will persuade Pyongyang not to break the moratorium.