At the climax of the Avengers, Tony Stark flies a nuclear missile through the wormhole created by the Tesseract. Shortly after he crosses the threshold of the wormhole and releases the missile, his suit's systems and even the ARC reactor appear to fail, and he passes out/goes into cardiac arrest. (This is an assumption on my part as the reactor no longer powering the electromagnet would allow for the shrapnel in his heart to continue moving further in.)

Throughout the major fight with the Chitauri he doesn't appear to take as significant damage as he does during his encounter on the Helicarrier, nor does the Mark VII armor appear to require significantly more power than the Mark VI.

So what would cause his systems to fail?

EDIT: I just rewatched the scene, and the suit appears to lose power just after crossing the threshold of the portal, as he's releasing the missile from his grasp, but Tony doesn't lose consciousness/go into cardiac arrest until just after the nuke makes impact.

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    didn't Jarvis point out that maneuvering a freaking nuclear missile was consuming power at a higher rate than his ARC reactor produced?
    – rsegal
    Commented Jul 10, 2013 at 17:26

9 Answers 9


The nuclear weapon he directed through the wormhole emitted an electromagnetic pulse which should cause any electronic device to stop working.

An electromagnetic pulse (commonly abbreviated EMP) is a burst of electromagnetic radiation. The abrupt pulse of electromagnetic radiation usually results from certain types of high-energy explosions, especially a nuclear explosion, or from a suddenly fluctuating magnetic field. The resulting rapidly changing electric fields and magnetic fields may couple with electrical/electronic systems to produce damaging current and voltage surges. --Wikipedia, Electromagnetic Pulse

He basically knew once he pushed the nuclear weapon through the portal he would not be coming back because he would have little or no technology at his control once the nuke went off.

EDIT: Having rewatched the movie, his suit loses power at the release of the missile. But this would not have caused his arc reactor to stop working, only the EMP would have done that. Knowing Stark, the arc reactor would be hardened and would restart after a reboot, as it did once he reached the ground. (Can't go around having a heart attack because you just survived and EMP, right)

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    Do EMPs still happen when nukes explode in space? It seems that the interaction with the explosion and the atmosphere results in the EMP.
    – user1027
    Commented Mar 7, 2013 at 21:04
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    It's not just the atmosphere (though there should have been at least some atmosphere leaving the portal, since I assume the portal worked both ways) the nuke still gives off a strong gamma ray emission which also affects electronics as well. Since the portal allowed traffic both ways, it could be assumed the region on the other side of the portal should have had enough atmosphere for Tony to be affected by the normal EMP effects when the gamma rays hit that atmospheric shell coming through the portal. Commented Mar 7, 2013 at 21:20
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    I'll have to watch it again, but doesn't Stark's suit and thrusters fail before the missile hits the mothership?
    – Steam
    Commented Mar 8, 2013 at 13:43
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    I do believe that throughout the entire movie, Tony didn't have a chance to recharge the Arc reactor / Iron Man suit. Jarvis was complaining about low power levels, so I suspect that it was a combination of Low Power levels (eg Thrusters giving out), and EMP effects that shut down the Arc Reactor (Life support / Dying). Commented Mar 8, 2013 at 20:34
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    I think all of the suits have their own internal reactors to reduce the strain on the one Tony uses for keeping himself ALIVE. I think he can use power from his person one, but I am certain JARVIS reminds him how dangerous that is all the time... Commented Mar 8, 2013 at 21:32

The answer is simple. The suit and reactor are general purpose and are simply not designed for deep space travel. He'd need a seperate single purpose suit and reactor for deep space travel else risk the suit and reactor shutting down.

  • This does make sense, given that he's designed several suits purely for space travel in the comics continuity.
    – Monty129
    Commented Jul 10, 2013 at 23:57

Why couldn't it be a different set of physical laws? Tony flew threw a portal that took him to another part of the universe that perhaps has different physics where the Arc Reactor wouldn't work.

  • I'm not a Physicist, but I'm pretty sure the Universal laws of physics would still apply even on the other side of the Universe.
    – Monty129
    Commented Jul 10, 2013 at 9:08
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    @Monty129: user probably meant to another Universe all together. But I don't have sufficient knowledge of Iron Man lore to determine if that would make sense.
    – bitmask
    Commented Jul 10, 2013 at 9:27
  • I suppose that's a possibility seeing as how Tony just flew through a hole ripped in the fabric of reality.
    – Monty129
    Commented Jul 10, 2013 at 23:56
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    Universal Laws of Physics do not apply to either the Marvel world, or the DC one. Just look at the Hulk; massive physical transformation without consuming massive amounts of corresponding caloric energy due to some gamma radiation absorbtion? Oh, and the intelligent magic hammer with a too-short handle built by dwarves.
    – Jersey
    Commented Aug 2, 2013 at 15:31

The Ark Reactor and Iron Man Armor simply ran out of fuel.

Iron Man had already drained a lot of energy in heavy firepower and flight maneuvers. At the time JARVIS dialed Pepper Potts, his blurring visuals displayed a sign of that. At that time, Iron Man was running on dying emergency power.

  • I just rewatched the scene, and the only significant damage he takes is from the crash landing after he flies through one of the serpent beasts, but it's still less than the damage the Mark VI suit took on the Hellicarrier, so I don't think it's because he's expended too much energy.
    – Monty129
    Commented Mar 9, 2013 at 17:56
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    @Monty129: Damage != expending energy. He's been fighting at full power for many minutes, he's redirected a nuke (which was traveling at considerable speed, changing the velocity requires enormous energy input), and flown in an environment very different from what the suit was designed to handle. It's all very power-intensive.
    – Jeff
    Commented Mar 9, 2013 at 18:46
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    @Monty129 Any canonical source to back this up?
    – user931
    Commented Mar 10, 2013 at 17:56
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    @Sachin Shekhar, I agree with you about the suit running out of power. jarvis said something like power is low to tony, and tony then put all power to thrusters to redirect the missile. I would like to ask another interesting question though: why did loki's scepter fail to control tony, my theory being that the arc reactor has a similar energy output to the tesseract, which was not able to overtake the arc reactor in tony's chest. now here is the complicated part. when loki was monologuing in the "boot" he mentioned using the tesseract as a warm light or something for humanity, ...
    – user15620
    Commented Jul 1, 2013 at 1:07
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    @Monty129: While flying around, energy use is much higher, and the armor needs to consume all energy it can just to keep Stark from falling to his death. In such an emergency, it's reasonable for the HUD, lights, etc. to go out. Once he's on the ground, the chest light, HUD, etc. can turn back on because the suit is no longer drawing more emergency power than the Arc reactor can provide. Commented Jul 1, 2013 at 1:39

I honestly just think it was the coldness of space he doesn't have a breathing apparatus or any of that in the suit for deep space flight. His suit prob froze up like it did when he went too high and with him running out of breath he passed out.

  • I believe one of the Iron Man movies shows him welding underwater, so he at least has a short-term oxygen supply. But then again, in Iron Man 3 it shows his suit filling up with water after he falls into the sea. Commented Jul 19, 2013 at 19:28
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    @Lèsemajesté it's actually in Avengers where he's welding underwater, but in the Mark VI suit. The Mark XLII suit from Iron Man 3 was a unique suit that was built as an experiment, so it probably wasn't designed to be hermetically sealed like the other suits.
    – Monty129
    Commented Aug 4, 2013 at 12:06

I am pretty sure Tony's Arc Reactor ran out of power. While this reactor is more efficient than the one he replaced in IM2, it's still a finite power source. Tony flew to Germany, captured Loki, fought Thor, repaired the Helicarrier, and flew back to Stark Tower all with the same chest piece. If you look at the HUD when Tony is approaching the tower, it reads, "RT OUTPUT 16%." So Tony's power was already dangerously low when he entered the fight with the Chitauri. Switching to the Mark VII didn't anything, because it still runs on the same chest piece. When Captain America warns Tony that the trip through the portal is a "one-way trip", Tony tells JARVIS to "save the rest" of his power for the return trip. Tony is lying to himself, refusing to believe that he could be sacrificing himself. The reality only sets in when the reactor runs out of power shortly after entering the portal.

The real question is: Why did Tony's reactor start working again after he was back on the ground? It should have been drained. My guess would be that there must've been a deleted scene where Thor used his lightning to recharge the reactor, which was foreshadowed earlier in the film, and was what happened in the animated Ultimate Avengers 2.

  • The reactor in the Mark VII suit was a separate reactor from the one he had powering all the previous suits. Power failure wasn't the issue.
    – Monty129
    Commented Jul 19, 2013 at 1:12
  • I have a follow-up theory. Tony tells JARVIS, "Save the rest for the turn." If the "turn" refers to changing the missile's trajectory, then I think Tony is putting put 100% of the reactor output into the thrusters. You can see the HUD output meters redline when the thrusters kick in. I think putting all the power into the thrusters left nothing for life-support and other functions. After jettisoning the thruster-pack and falling back to Earth, the ARC Reactor has a chance to recharge the suit's capacitors and resupply power to Tony. Commented Jul 19, 2013 at 17:45
  • There are two reactors in play, the one embedded in Tony's chest with the Vibranium core, and the one in the Mark VII armor that provides power solely to the Iron Man platform. Even if the one in the armor ran out of power (which it can't because it's a perpetual motion machine) the one in his chest wouldn't.
    – Monty129
    Commented Jul 19, 2013 at 18:53
  • I agree there are 2 reactors in play, but I wouldn't put it past Tony to allow for an armor to use power from both if he needed to. And I don't think the one in the suit was used up; he was just using 100% of its gigajoules/sec as fast as it could generate it. I just think he sacrificed power to all the subsystems so that he could increase power to the thrusters. Even if his chest reactor was still protecting his heart, it's possible he wasn't getting any oxygen/heating while in space. It wasn't until the thrusters jettisoned that power could start redistributing back to the other systems. Commented Jul 19, 2013 at 21:14

If you notice, Tony does tell J.A.R.V.I.S to "save the rest for the turn" prior to even ascending Stark Tower. He knew that the RT was near depletion. We also have to remember that he didn't change it out during the entire movie, unlike in the previous Iron Man films. It should also be important to note that restarting the Helicarriers probably took a huge amount of power...

  • Your answer is dealing with three different ARC reactors though. The interchangeable core version from Iron Man II (3rd generation) was obsolete after the 4th gen version with the Vibranium core. He doesn't need to swap them out after that one. The Mark VII suit has it's own independent core as well, so that's also not a factor.
    – Monty129
    Commented Aug 4, 2013 at 12:03

First of all, the nuclear bomb detonates after the suit shuts down.

So the EMP has absolutely nothing to do with anything.

I am pretty sure his suit of armour simply shorted out because of deep space radiation frying its electronics due to inadequate shielding.

The Earths magnetosphere is created by the earth's magnetic field, and it acts as a shield against charged particles and ionizing radiation carried by the solar wind, or infrequent cosmic rays that originate from intragalactic space and pass through the heliosphere.


The heliosphere is a vast, bubble-like region of space that surrounds the solar system and is created by the Sun's solar wind. It acts as a shield against the charged particles and ionizing radiation carried by the interstellar wind and cosmic rays.


My point is that the earth and by extension, all of mankind and our electronics are protected by two vast barriers from harmful cosmic rays and ionizing radiation.

By travelling through the wormhole above New York, Tony travels into the deep reaches of space where he was most likely exposed to all sorts of cosmic rays and ionizing radiation that could have easily shorted out his armours highly sophisticated and very sensitive electronics and had he not fallen back down to earth would have outright cooked him inside his suit if the nuke didn't reach him first.


This is a guess, but i think it should not be overlooked. In IRON MAN 3 they went out of their way at least three or four times that I saw, mentioning , 1.) HOW DID YOU GET OUT OF THAT WORM HOLE, 2.) TONY EXPLAINING ABOUT "WE CREATE OUR OWN DEMONS", 3.) I'M A PIPING HOT MESS NOTHING HAS BEEN THE SAME SINCE NEW YORK,4.) AND ALSO WHEN HES DREAMING ABOUT CROSSING THE WORMHOLE AND PEPER GET HANDLED BY MARK 42. How did he get out of the worm hole? if you can see tony never made it through, yet he appeared on earth somehow, I DIDN'T PAY ANY ATT. TO THAT AT FIRST I THOUGHT HE DID MAKE IT. Powering the mini ARC is only an issue in IRON MAN 1 AND HALF WAY TO 2 because of his fathers far superior design the only issue he had is powering his father ARC for the first time in AVENGERS AND IRON MAN 3. so why did it fail when he crossed dimensions? we vibrate at a frequency similar to our planet, it is believed in theory that other dimensions vibrate at a different freq. you can also see this in Justice League: The Flash point Paradox. The Iron man suite went through a significant frequency change something it was not designed for. I'm not going to make this longer I.m just throwing this out and let me know what you guys think. Rumors of Dr Steven Strange finally coming out. Stan Lee mentioned something might be out "dont know what" in iron man three about Dr Strange. confirmation of Dr Strange coming out in Thor 2 the guardians of the universe. Demons mentioned in Iron Man 3, tony stark finally got something unexplainable. as far as I know Dr Steven Strange deal with demonology is far more powerful than anyone of the Avengers, wich can explain why Thanos is coming out.. Thanos power if far grater than any other and also known that the only battle in comics took place between Thanos and Odin father of Thor and their battle was so cosmic it shook all universes. Also Scarlet Witch is to come out as an AVENGER she deals with majic and the unknown. Dr strange is also known for his apearances with others heroes such as spider man, where he simply apears out of the blue to help them with something far greater than their powers or science can handle. witch led me to this, WATCH AND TELL ME YOUR OPINION.

OR YOUTUBE Doctor Strange - 13. "The Nexus"

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    Hello and welcome to SF+F.SE. A little (actually, a lot..) of formatting would be very welcome to be able to read this long answer of yours :)
    – Kalissar
    Commented Sep 8, 2013 at 9:35
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    It's an interesting theory (from what I can make out, it is all over the place) However the portal wasn't a dimensional barrier, but one through space to another part of the galaxy.
    – Monty129
    Commented Sep 8, 2013 at 18:39

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