"B612 Foundation" . "Planetary defense" . . . "B612_Foundation#Tom_Gavin.2C_Chair.2C_Sentinel_Standing_Review_Team" . . . . . . . "B612_Foundation#Dan_Durda.2C_Board_Member" . . "Clark Chapman" . . . . . "B612_Foundation#Clark R. Chapman" . . . "2002-10-07" . . . . . "B612 Foundation#Dan Durda" . . . "Dr. Tom Jones" . . "B612_Foundation#John_Troeltzsch.2C_Sentinel_Program_Manager" . . . "B612 Foundation" . "Tom Gavin" . . . . . . . . . "B612" . . . "John Troeltzsch" . .