Can You Guess Which Rocker This Mustache Belongs To?

As far as mustaches go, this bushy piece of facial hair has been a distinguishing feature for one of rock's top bassists. This musician made his name in not one, but two major classic rock bands and he's also done session work for artists ranging from Eric Clapton to Willie Nelson, Barbra Streisand to Joni Mitchell.

Think you know who this rocker is yet? Here's another hint: In addition to music, he also has a defense consultant career to fall back on, finding an interest in and teaching himself about missile defense systems. So who is this man who could possibly hide a missile behind his facial brush?