The F-35 is the hugely expensive, and hugely complicated, fifth-generation stealth fighter jet. Perennially delayed and wildly over budget, it's had its share of problems and rightly earned piles of criticism. So here's some good news for once: The plane—maybe the most expensive weapon ever developed—has successfully taken off from a ski jump.

Before you start laughing, this is actually a significant milestone. The F-35 will come in a number of variants for different operational profiles (one source of complications and cost overruns), including the F-35C, designed for carrier operations with hardware allowing it to land and launch from flat-top aircraft carriers like US Navy's Nimitz and Ford class aircraft carriers, as well as folding wings and some other accoutrements. The F-35A is a more conventional fighter meant for use by the US Air Force and other land-based air forces.

Then there's the F-35B. It's the short takeoff and vertical landing (STOVL) variant. It's meant to be a replacement for the Harrier "hover jet", and it's able to take off from much smaller ships than the F-35C. It uses fancy hardware to aim engine thrust down, allowing the plane to take off and land at much slower airspeeds or even completely vertically, helicopter-style.

See, full-size aircraft carriers like the American Nimitz class—with longer runways and catapults to make taking off feasible—are incredibly expensive, and many of our allies can't justify the cost. Instead, they build smaller carriers with ski jump-like ramps at the end to assist planes in taking off.

The upward-sloped ramp at the bow simultaneously launches the aircraft upward and forward, allowing planes to take off with more weight onboard and with less speed than horizontal launch systems. Basically it's about saving money, because the ship can be a lot smaller and thus cheaper to build and run. They're used by navies around the world, including those of Britain, Australia, China, India, Italy, Russia, and Spain. The British, Italians, and Australians are all considering the F-35B. The US Marine Corps has committed to buying a number of them as well.

Last week, a BAE Systems (one of the main contractors on the F-35) test pilot successfully flew the F-35B off a ski jump for the first time at Naval Air Station Patuxent River, Maryland.

To make the process easier, the F-35B automatically adjusts control surfaces and nozzles for takeoff, allowing the pilot to focus on other things—and again showing how freaking complicated this thing is. If you look at the rear of the plane, you can see the thrust vectoring nozzles on the main engine pointing downward to mix lift and propulsive thrust, helping the plane get airborne.

We're sure the myriad companies involved in building the F-35B will get it all figured out (eventually), and that it'll be awesome once they do. But boy is it costing a lot of money. Depending on who you ask, the whole F-35 program will cost more than $350 billion over its lifetime (it got started in 2006), so it's really important that it, you know, work. This test is one small step in making sure it does.