Sure, this variation of headstand seems to defy gravity, but it's not impossible. It's exciting to try to stay balanced on your head and palms, since it's something we hardly ever do. A word of caution though — this is a very challenging pose that requires extreme balance as well as upper body and core strength. You should be a master at Bound Headstand as well as Tripod Headstand before attempting this pose to prevent injury.
If you feel confident in both those headstand variations, here's a trick for getting into Iron Cross: start off with your elbows bent and your hands 10 inches or so closer to your head than they are in the photo. As you feel ready, start to hop them out wide until your arms are straight. Engaging your legs and actively pulling your feet toward the ceiling will help take some of the pressure off your head. Once you find the balance, you'll feel so proud you'll want to scream, "Look at me!"