Calling it a helmet misses the point, it is an augmented reality device. The original design goal was to make the aircraft effectively transparent, the pilot could "see" 360 degrees through the aircraft's sensors. I think the milliseconds of lag on the first generation made this impractical, but I haven't read about the new generation.
It was designed before comparable devices like the hololens, it is built to be extremely reliable under changing temperatures and high G-loads, plus being hardened against EMP and radiation. and the whole development program's cost is spread over just a few hundred aircraft. Facebook paid $3 billion for Oculus, before they sold a single device. Based on the 231 F-35s currently in service, the DOD paid $9.25 billion for this helmet system, which started development much earlier. Zuckerberg had the advantage of watching numerous small companies and acquiring one when they were successful, DOD had to foot the bill for every single mistake.
[It's a pretty awesome helmet.](http://gizmodo.com/i-wore-a-400-000-f-35-helmet-and-it-blew-my-mind-1779125567
) It literally gives the pilot superpowers. X-ray vision, infrared vision, omni-directional input from the plane's cameras. Which, you know, is helpful if another plane is trying to shoot you.
And this sort of development, usually in conjunction with private military contractors who patent much of the tech, tends to trickle down into civilian hardware after a few years. So soon enough you could see all that cool stuff embedded in your motorcycle helmet, or the dashboard of your car.
But yeah, let's just bash on the cost of the hardware without any kind of context. That's fun.
That helmet costs $400,000 largely because:
1. It projects video onto the visor, replacing the HUD of a normal fighter jet. Combined with the F-35's DAS system that provides spherical thermal vision, [it means pilots can look through their legs and see the ground below them.](https://www.youtube.com/watch?v=w0btzIvlScI
) It also more importantly displays augmented reality symbology to show where allies are, where threats are, flight information like speed / altitude, etc.
2. The cost also covers the specific computer system that the helmet plugs into (there's multiple computers on the jet - think of it as a specialised GPU for the helmet).
3. It's designed to protect the pilot from 700mph winds and from debris when the thick polycarbonate canopy above them is detonated during an ejection.
4. While doing all that, it has to weigh less than 4.7lb so that there's a low risk of (primarily smaller / lightweight) pilots breaking their neck after ejection, when their parachute opens and they're at risk of having their neck snap backwards. There was controversy last year about reports that indicated that the helmet wasn't safe for pilots that weighed <136lb, but they've since brought out a lighter version of the helmet.
5. It replaces the need for pilots to wear night vision goggles, which normally use batteries, add weight, reduce your FOV, takes minutes to setup, etc. Instead the F-35's helmet has a night vision camera built into the forehead that switches on / off with the press of a button.
Well it's not exactly a fucking bike helmet
ITT people that make assumptions based on only the title
Imagine if Monster Cable had this contract. One helmet? That will be $40,000,000,000, please. It has gold connectors.
I mean the aircraft itself costs around $95 million, so it's a relatively small amount of money in comparison.