Dear Reader,

This blog seeks to empower readers to do their own intelligence analysis, with simple, accessible tools. The calculation of  North Korea’s ICBM test Succeeds  is something you could do on a napkin while waiting for your sushi. And unlike the news, it outlasts the event itself, as something you can use at a later time. It would be really cool if I could give you a feeling for the physics with something so simple. Alas, it misleads.

The outside estimate of range is given by the Union of Concerned Scientists, as 4800km = 3000 miles, short of the 4800 miles required to hit the U.S. The distance from Pyongyang to Anchorage is 3723 miles. If Anchorage is expendable, Seattle is 4700 miles distant.

The actual math for the range of a ballistic missile is complicated, unrevealing, and useless to the readers of this blog. I did a somewhat more involved calculation to see if there is something you can put on your napkin the next time North Korea launches a missile almost straight up.  This is the new rule-of-thumb for use on cocktail napkins:

The range of the missile when used as a weapon is approximately twice the height it can reach when aimed almost vertically.

This is for public use, to understand the news better, and does not replace or challenge estimates based on engineering calculations.