 So one of the things that happens is when you're going through to verify your requirements, sometimes you have to build these big complex systems. And what you see on the next chart is probably one of the biggest, most complex. So what you see there is a command and service module from Apollo inside a gigantic chamber. And that chamber is one where it's down at Johnson Space Center. And what you can do there is you can suck out most of the air, create a pretty good vacuum, and you could raise and lower the temperature to the temperatures you would see in space using cryogenic things like cryogenic nitrogen, liquid nitrogen, to cool the inside of the chamber. You can heat the chamber up with very bright lights and heaters. And so you could replicate a space environment to see, again, I have all these requirements that say my vehicle must work in a space environment. I need to be able to put this thing in a chamber to see if it will work as close as I can simulate in a space environment on Earth. So what you see here is that when you do that, you might have to actually write some additional requirements that are going to help you do the verification process.