We're celebrating the May 7 (April 28 internationally) release of "Iron Man 2" with Iron Man Month 2010! Get ready for a monthlong mega mix of all things Shellhead right here on Marvel.com!
By Ryan Haupt
Marvel has a proud history of science-heroes, with many Marvel heroes emerging as accidents of science or the product of their own scientific ingenuity. Tony Stark is one such hero and in order to analyze his plausibility we brought in an honest to goodness scientist to figure it out for us.
Ryan Haupt holds two Bachelor's of Science in Environmental Geology and Ecology & Evolutionary Biology from the University of California, Santa Cruz and is going back to school in the fall to get a Masters in Paleontology from Vanderbilt University. Currently, he helps research a variety of topics ranging from stable isotope geochemistry, mammalian paleoecology and oceanographic paleoclimatology. He hosts the podcast "Science... sort of" with two grad student friends where they hang out while talking about science and geek culture. He occasionally fights rabid and rogue elephant seals, but only for science.
Think back to the first trailer for the first "Iron Man" movie, particularly the point in which we see Tony in the suit breaking the sound barrier. If you're confused by how you can 'see' something break the sound barrier, just Google the phrase and you'll see what it means. While many science-minded viewers excited pumped their fists due to the film's accuracy, it does present a challenge: How on (or more accurately off) earth could Iron Man possibly fly?
If you read the first Marvel Science article on Iron Man's armor, you'll recall the serendipitous discovery of the Tokamak reactor. Tony could use the reactor to power his suit, providing an elegant solution to the magic-science power-donut problem. Well today, Iron Man goes 2-for-2 with the Variable Specific Impulse Magnetoplasma Rocket (VASIMR). Don't be intimidated by the name, the only two terms you really need to focus on are "magnetoplasma" and "rocket." The way this rocket works is pretty simple, especially if you remember the previous article. Quick recap though: plasma responds to magnets because it's full of ionized subatomic particles. The chest reactor's goal is to keep this plasma contained, but a rocket like this one's goal is to push the plasma out the bottom with enough force to provide thrust.
Tony already has the basics in place, a supply of plasma, superconducting electromagnets to contain the plasma and power to run those same electromagnets. Check out this diagram from NASA: http://spaceflight.nasa.gov/shuttle/support/researching/aspl/images/vasimr.jpg. You'll notice those are the same basic ingredients to build a VASIMR.
Again, like the Tokamak reactor, the VASIMR has its own set of challenges for Tony to overcome. The VASIMR is classified a 1 on the technology readiness level, which means it's still in the "basic research" phase of existence, a far cry from operating in a battlefield. Right now they're really big but with enough energy to power the thing it wouldn't be impossible for Tony to scale it down for his needs as he did with the arc reactor. Another stumbling block so far? VASIMR prototypes have only been tested in a vacuum. It's a bit unclear if this means they only operate in a vacuum but they've been proposed as a high-atmosphere form of propulsion, which implies functionality in air, not just in space. Finally, the VASIMR produces a lot of magnetic field energy. So much so that some critics of the design worry it could affect the Earth's magnetosphere, and that would be bad, because we need the magnetosphere to, y'know, live and stuff. Tony can insulate the suit against the strong magnetic fields, but the Earth can't. Let's assume since he's scaled down the rocket to boot size the Earth can take the strain.
Well last week the question of fuel was also mentioned, specifically where the raw material to create the plasma comes from. Since both the rocket and the reactor need hydrogen as fuel they might as well get it from the same source, and the best source is probably Tony himself. An adult human male carries about five liters of blood in their body. A little more than half of that blood is plasma. Plasma is 90% water. Water has two hydrogen's right there for the taking with the help of a little electrolysis.
Physicist Ben Tippett did some back of the envelope calculations based on these assumptions and the results showed that Tony would be burning through about a liter of water per hour of running the reactor at full capacity. This would dehydrate you and fast, so it's a good thing Tony drinks plenty of fluids. But as long as he kept enough water in his system he'd have all the fuel he needs with no giant tank. Which is good because a giant tank would make the whole contraption pretty hard to steer, right?
Some aircraft, like the F-22s Tony engages in "Iron Man," are naturally unstable. A paper airplane model of the F-22 would not fly in a straight line like a Cessna would. But computers, in this case called a control system, can handle the discrepancy with the use of control laws. Control laws are a set of physics calculations which take in a lot of data about the aircraft and its surrounding environment and in turn make adjustments to the various control surfaces across the aircraft. These control systems come standard on all modern aircraft and work so well that according to aeronautical engineer Jacob Stump, every modern aircraft flies better than even the best aircraft available in the 1970s.
High school physics books tell us that planes fly because of the airfoil shaped wing that create a pressure differential on the top and bottom creating lift. And this is all well and good, but the Iron Man armor has no wings. Well neither did the Apollo Saturn V rocket, and that thing was huge. All it takes is enough thrust in the right direction and you can get in the air.
But before control, we must have stability and this is where all the computers and control surfaces discussed above are used.
Flying stable is a good step in the right direction, but mobility is even better. After all the science it took to get us this far, the actual control becomes surprisingly simple. Tony has repulsors in his hands which could easily provide enough force to twist and turn him, provided his legs and torso also moved accordingly. The suit is likely locking Tony's legs into the appropriate position during flight. Tony's legs need to be rigid and directly behind his torso, where most of his weight is, in order to prevent him from spinning like a pinwheel instead of flying straight ahead. Leave it to Jarvis to make adjustments from there.
Real World Personal Flight Devices
These examples more than anything else emphasize how difficult the issues brought up earlier in the article will be to overcome. Pilot Yves Rossi's self-built and operated jetpack can only be used if you're willing to throw yourself out of a plane, which probably isn't a very big deal if you're already willing to use a jetpack, but it does drive home the difficulty of thrust. The Jetlev-Flyer uses water to propel a person skyward, and as you can see here, this jetpack comes complete with a long hose to provide the water to be used for thrust, which emphasizes the fuel issue. And the Martin jetpack takes two dudes standing on either side to help you keep the darn thing under control even in a warehouse with no wind and/or gunfire.
So as expected, none of these options work all that well for fighting the Air Force single-handedly, but they're probably much more exhilarating than the latest flight simulator. Speaking of videogames, we should probably figure out just how Tony interacts with the suit to get it to do what he wants. Until next Tuesday...
This article would not have been possible without the help of some spectacular science-types who have specialized in fields I ran screaming from my freshman year of college. I'd like to thank Ben Tippett (University of New Brunswick), David Tsang (CalTech) and Jacob Stump (Embry-Riddle Aeronautical University). I couldn't have done this without their knowledge and willingness to converse endlessly about the awesomeness that is the Marvel Universe. Thank you very much. To anyone I've forgotten to mention, thank you too.
Robert Downey Jr. reprises his role as billionaire industrialist Tony Stark, aka the super hero Iron Man in this sequel to the 2008 blockbuster. RDJ, Paltrow, Cheadle and Rockwell are joined by Samuel L. Jackson as Nick Fury, Scarlett Johansson as Black Widow and Mickey Rourke as Whiplash. Jon Favreau once again takes up the directorial reins for Marvel's armored avenger.
"Iron Man 2" is one of a continuing slate of films being produced by Marvel Studios based on the Marvel characters, including "Thor" on May 6, 2011, "The First Avenger: Captain America" on July 22, 2011 and "Marvel Studios' The Avengers" on May 4, 2012.
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