Studies by the Pentagon and the two contractors for the Joint Strike Fighter have concluded that its reduced radar and heat signatures will keep it safe from whatever radar system follows the emerging Russian S-400 system, that being through 2025. The JSF has the radar signature of a golf ball; the F-22 Raptor has the radar signature of a marble. The main advantage of both aircraft, however, is that their stealth coatings need only 10% of the maintenance that the B-2A Spirit Bomber needs.--Stephen V Cole