How Nuclear ICBM “Re-Entry” Vehicles Destroy Targets

By John Warnock, Warrior Senior Fellow

You Might Want to Know: What are “re-entry vehicles”? Why do we need them? How do they work? What are MIRVs? How do they work?

If you know what happened to the Space Shuttle Columbia in 2003, you know why nuclear warheads need re-entry vehicles.

Anything that gets going fast enough to get into orbit, which is 17,500 miles an hour, will still be going thousands of miles an hour when it comes back into the atmosphere. At that speed, friction with the atmosphere generates temperatures of thousands of degrees on the surface of the vehicle. Without a heat shield, the vehicle will burn up.

On its way up into orbit, Columbia lost some tiles in the heat shield that was supposed to protect it when it came back and re-entered the atmosphere. Where the tiles were missing, the friction heated the Shuttle up past what it could take. It broke apart. We saw pictures of the white trails of the fragments streaking across the sky. All seven astronauts were killed. A terrible thing.

Intercontinental Ballistic Missiles don’t go into orbit but they propel their warheads far above the atmosphere. Different ICBMs propel their warheads to different altitudes but the apogee (high point) can be more than seven hundred miles above the earth. Coming back, the warheads re-enter the atmosphere at about sixty-two miles above the earth (Our atmosphere extends only that high, did you know? That’s not very high.).

When the warheads re-enter the atmosphere, they are still travelling at many thousands of miles an hour. Fifteen thousand miles an hour, it could be. Much faster than any bullet. They will keep most of that speed all the way down. If the warheads weren’t protected against the heat, the friction with the atmosphere would heat them up so much they couldn’t be counted on to work the way we want them to.

Re-entry Vehicles use different special materials developed by materials scientists to keep the warheads from overheating. Some RVs “ablate” (partially vaporize) their surfaces coming in. This carries off some of the heat.