» more from Defense

9. UGM-133 Trident II

Total program cost: $40.6 billion

The Trident II is an intercontinental-range ballistic missile launched by submarine. Manufactured by Lockheed Martin, it was meant to improve upon the Trident I missile in terms of capacity and payload, and it can be used for a pre-emptive attack.

"Although it's expensive, it's been a highly successful program," Wheeler said. "Both the submarine and the missile part of the system have been around a long time, and although they're expensive, they have done what they're supposed to do."

He added that four of the submarines were converted to launch cruise missiles against targets in Libya earlier this year.

Stocktrek Images | Getty Images