Originally Posted by rickair7777

Liquid fuel engines are VERY complex, and often stressed right to the engineering limits (no 150% ultimate load).

Look at recent history...I can't recall any solid fuel booster failures in the last two decades, but there have been numerous, recent, major malfunctions of liquid engines.

Even the shuttle Challenger booster did not fail...it leaked, but it continued to function normally. The leak ignited the liquid fuel tank.

The military invariably uses solid boosters in all applications for reliability and safety...the only justification for the cost and risk of liquid is if you have to get something heavy into orbit, or move it around once you get there.