1.   Each year, supersonic bombers are dispatched to drop explosives on the ice, using the ice dams for target practice.

2.   It was a big improvement for the supersonic bomber.

3.   Since then, the supersonic bomber has had a history of design problems, cost overruns and fatal crashes.

4.   The footage of supersonic bombers dropping explosives on the ice of a great Siberian river was dramatic enough.

5.   NASA had it outfitted as a flying laboratory and it was upgraded with engines from the Blackjack supersonic bomber.