An alternative is to call Str on the object instead, which produces formatted output (I think this is undocumented still)...
Type Rocket Field x Field y Field fuel Field name$ End Type r.Rocket = New Rocket r\x = Rand (0, 639) r\y = Rand (0, 479) r\fuel = Rand (0, 100) r\name = "Player 1" Print Str (r)