In the last year, the U.S. Air Force has introduced the use of robots to reduce the maintenance efforts required to keep their B-2 bombers flying. The B-2 uses a stealth (anti-radar) system that depends a lot on a smooth outer skin. That, in turn, requires that the usual access panels and such on the B-2 must be covered with tape and special paste to make it all smooth. And after every flight, a lot of this tape and paste has to be touched up. all this takes at lot of time, being one of the main reasons the B-2 required 25 man hours of maintenance for each hour in air. Since most B-2 missions have been 30 or more hours each, well, do the math. The main base for B-2s is in Missouri, and over a thousand maintenance personnel are assigned to take care of 21 aircraft there. A team of four robots can now apply a liquid coating to B-2s, thus cutting maintenance hours in half. But B-2s still requires a special, climate controlled hangars. There are some portable B-2 hangers, that can be flown to distant bases, thus keeping the bombers in the air less, and reducing the amount of maintenance needed. B-2 quality hangers have been built at Guam, in the Pacific, and Diego Garcia in the Indian ocean Still, the cost to operate the B-2 is over three times that of the B-52. If stealth is not an issue (not much enemy opposition), than its a lot cheaper to send a B-52. This is exactly what the air force does most of the time. But in a war with a nation possessing modern (or even semi-modern) air defenses, the B-2s can be very valuable. Costing over two billion dollars each to buy, and very expensive to operate, the B-2s provide that extra edge. No other nation has anything like the B-2s, although many are working on ways to defeat its stealth and knock them down.