The U.S. Air Force and defense contractor Northrop Grumman have begun construction of the first B-21 Raider bomber. The airplane, which will carry both conventional and nuclear payloads, is the U.S.’s first first new heavy bomber in more than thirty years. And despite a plane already being assembled, you haven’t seen it yet. All you’ve seen is a cartoon. There are no real public photographs yet at all.

The Raider will be a stealthy, expensive, bomb-dropping machine, capable of flying conventional strike missions against countries such as Iran or Strangelovian missions carrying thermonuclear bombs, also against Iran.

Air Force Chief of Staff David Goldfein the service is building the first B-21 Raider bomber, according to The National Interest. The bomber is named after the force of B-25 Mitchell bombers that took off from an American aircraft carrier and raided Japan five months after the attack on Pearl Harbor.

The initial development contract for the B-21 was awarded to Northrop Grumman in 2015, with the name “Raider” and an image of the aircraft in 2016. In 2017, The Los Angeles Times that Northrop was planning to build the aircraft at Air Force Plant 42 outside Palmdale, California, where the B-1B and B-2 bombers were built. The exact program cost for the bomber is unknown, but estimated to cost between $80 and $.

The Air Force has big plans for the B-21, planning to purchase 100 bombers to replace the B-2 Spirit and B-1B Lancer, at a cost of $656 million each in 2019 dollars. The Air Force’s version of the F-35 Joint Strike Fighter, by comparison, . The service has , and one think tank, the Center for Strategic and Budgetary Assessments, the service buy as many as 288 bombers.

Not much is known about the B-21, with nearly all details classified. The B-21 is a flying wing design, basically consisting of a large set of wings with a fuselage blended in-between. Like the B-2, the aircraft lacks a tail and horizontal and vertical stabilizers. Unlike the serrated rear of the B-2 which ends in five points, the B-21 basically resembles a big “W,” ending in just three. The aircraft looks about as big as the B-2 but there are suggestions it could be smaller.

Other details, including stealth, electronic warfare, power plants and weapons are all unknown. The B-21 will almost certainly be stealthier than its immediate predecessor, the B-2, with more than thirty years stealth advances to draw upon. It will likely include not only a smaller radar signature but also a smaller infra-red signature, to minimize vulnerability to new on Russian and Chinese fighters. It will likely be powered by two turbofan engines but almost certainly remain, like the B-2, a subsonic aircraft.

Sonic booms aren’t exactly stealthy, you see. People tend to look when there’s a big loud noise.

Of course, bombers are meant to drop bombs, and here’s where things could get weird. Modern bombs, aimed with the help of lasers or GPS, are unfailingly accurate—even in the face of modern jamming. A bomber does not necessarily need a large bomb load to strike its target. That having been said, the B-21 will probably require the ability to carry at least one bomb. Twenty one feet long, nearly three feet wide and weighing 30,000 pounds, an MOP can attack deeply buried enemy bunkers and command centers, penetrating 200 feet of reinforced concrete reinforced to up to 5,000 pounds per square inch. One B-2 can carry two MOPs.

The bomber will also carry nuclear weapons, allowing it to fight a nuclear war. The B-21 will likely be capable of carrying the B-61-12 thermonuclear gravity bomb, which features a “dial-a-yield” capability allowing its destructive potential to be set to the equivalent of 300 tons, 1,500 tons, 10,000 tons, or 50,000 tons of TNT (by comparison, Hiroshima was 16,000 tons of TNT). The B-21 will also likely carry the , a nuclear-tipped cruise missile currently under development.

One thing we do know is that the B-21 will be a ghost bomber, with the ability to be flown remotely and without a human crew.

Another feature the B-21 will almost certainly have is very long legs. A bomber must be able to strike its target, and that could mean traveling hundreds of miles to avoid a barrier of air defenses such as the . Modern aerial refueling tankers are vulnerable in fights against countries like Russia and China, with the latter specifically developing very long range missiles, such as the , to shoot them down in wartime.

The new bomber could come with a few surprises. The Air Force has somewhat cryptically stated the B-21 is part of a “family of systems,” with the bomber in the center. These systems are likely defensive in purpose and could include air-launched decoy drones that mimic the bomber, sending enemy defenders on a wild goose chase. Alternately, a B-21 could team up with a drone capable of acting as a communications or navigation node, in case the U.S. military’s satellite network is disrupted.

The first B-21 Raider is expected to take flight in 2021, with the first aircraft combat ready in the mid-2020s. One aircraft the new bomber won’t replace, at least right away: the venerable, extremely u-stealthy B-52H Stratofortress. The Air Force , when average airframe will be an astonishing 88 years old. At that point the old bomber could be replaced by a new lot of Raiders, or, more likely, it could pretty much just fly forever.