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Lana Lang (Because no one really gives Lana enough love) is the newest recipient of the superhero lottery. Boasting an impressive repertoire of powers, yes, but there are only a couple of ones we care about. The ability of flight and superspeed.

This lethal combination has our intrepid heroine the most sought after weapon in any arsenal, being compared rather favorably to a tactical nuke. The idea being that no one could detect if she was deployed until after the effects are witnessed. But, is this really the case?


Some very interesting reading to be had here and here, but nothing strongly conclusive or that truly agrees.

What I'm looking for is strong proof of whether current technology can in any way detect a human flying at >3000m altitude at supersonic speeds (lower bound of 1195 km/hr or Mach 1).

If, for the sake of hard science answers, it is easier to assume a 100kg sack of meat traveling at those speeds rather than a person, you may substitute as such (The sack of meat cares not about forces or breathing after all). Also, if it is easier to use an upper bound speed, for whatever reason, you can assume the upper bound of 4939.2km/hr or Mach 4.

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The short answer is yes.

Anything traveling that fast in the atmosphere will encounter enough friction to develop considerable heat. This will have create multiple wavelengths of IR emission to detect. There has been considerable interest in developing better IR detectors for many diverse reasons in the last decade; overflying an area with IR cameras in winter can determine which homes could save a lot of money with added insulation.

Night vision and infrared radar has gotten considerable darpa funding. CCDs (Charge Coupled Devices) that are used as image sensors for consumer gadgets like phones and cameras see into the near infrared and actually have an IR filter on the lens assembly.

This link will give you a great deal of information on IR instrumentation development in the last decade:
https://doi.org/10.1017/CBO9780511564727.010

The following details fourier transform approaches to making radar all digital:
https://doi.org/10.1017/S1759078717000782

Automotive anti collision systems have driven development to make single chip low cost radar chipsets, some of them into millimeter wave bandwidths:
https://doi.org/10.1017/S1759078712000797

This details adding a passive IR radar to an aircraft to supplement information to pilot and autopilot:
https://doi.org/10.1017/S1759078712000220

I was also looking for a citation (and failed to find) an article I read a few months back, that detailed using a satellite based modulated thermal emitter and ground based IR detectors to implement a wireless network. The FCC and its equivalent in other countries has a huge challenge in regulating the radio spectrum, so a communication platform outside "normal" radio frequencies would be a plus. The international journal of microwave and wireless technologies alone will give you several months worth of reading on the topic.

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  • $\begingroup$ But can you find a source for how much heat an object makes moving quickly in the upper atmosphere? I'm pretty sure you are right, but I think it is an important link in the chain. $\endgroup$ – user25818 Nov 3 '17 at 21:21
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    $\begingroup$ @notstoreboughtdirt The op question was about detection methods. I answered that thoroughly. As to how much heat is generated, that would require a ridiculous amount of fluid dynamics computation after making an assumptions on the reynolds number of superman. And it is safe to say that the quantity of heat developed would be orders of magnitude higher than needed for detection methods already available. Look at a few NASA studies into shuttle reentry eg ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19820015616.pdf So I respectfully disagree. Not important. $\endgroup$ – steverino Nov 3 '17 at 21:45
  • $\begingroup$ en.wikipedia.org/wiki/Concorde#Heating_problems: the Concorde was limited to flying at Mach 2.02, because any faster than that would generate too much heat. Temperature at Mach 2.02 was 261F. $\endgroup$ – Dan B Nov 3 '17 at 23:49
  • $\begingroup$ @secespitus I just reread my answer and wished to compliment you on the great job of making it more readable with the edit. $\endgroup$ – steverino Nov 5 '17 at 1:16
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I see that there exist radar devices used for tracking howitzer shells and small missiles. I think such devices should be able to detect Lana.

https://en.wikipedia.org/wiki/Counter-battery_radar

The Royal Radar Establishment in the UK developed a different approach for their Green Archer system. Instead of a conical beam, the radar signal was produced in the form of a fan, about 40 degrees wide and 1 degree high. A Foster scanner modified the signal to cause it to focus on a horizontal location that rapidly scanned back and forth. This allowed it to comprehensively scan a small "slice" of the sky. The operator would watch for mortar bombs to pass through the slice, locating its range with pulse timing, its horizontal location by the location of the Foster scanner at that instant, and its vertical location from the known angle of the thin beam. The operator would then flick the antenna to a second angle facing higher into the air, and wait for the signal to appear there. This produced the necessary two points that could be processed by an analogue computer. A similar system was the US AN/MPQ-4A, although this was a somewhat later design and somewhat more automated as a result.

However, once phased array radars compact enough for field use and with reasonable digital computing power appeared they offered a better solution. A phased array radar has many transmitter/receiver modules which use differential tuning to rapidly scan up to a 90 degree arc without moving the antenna. They can detect and track anything in their field of view, providing they have sufficient computing power. They can filter out the targets of no interest (e.g., aircraft) and depending on their capability track a useful proportion of the rest.

Counter-battery radars used to be mostly X band because this offers the greatest accuracy for the small radar targets. However, in the radars produced today C band and S band are common. The Ku band has also been used. Projectile detection ranges are governed by the radar cross section (RCS) of the projectiles. Typical RCS are: - Mortar bomb 0.01 m Artillery shell 0.001 m Light rocket (e.g., 122 mm) 0.009 m Heavy rocket (e.g., 227 mm) 0.018 m

I assume those radar cross sections from Wikipedia are m2 not m. But not sure enough to edit the Wikipedia article!

The radar cross section of a human is 1 m2. Larger than a shell. Which makes sense.

Muzzle velocity of the fastest artillery shells is 1067 m/2. That is 3841 km/hour. https://en.wikipedia.org/wiki/Muzzle_velocity

You have Lana flying between 1195 and 4939 km/hr.

I conclude that a device capable of detecting a substantially smaller object moving at comparable speed could also detect Lana.

Re: enough love - Kristin Kreuk's Lana on Smallville was adorable!

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https://futurism.com/see-the-worlds-fastest-cameras-in-action-4-4-trillion-shots-each-second-video/

A 4 trillion FPS camera could definitely catch her.

You would probably want a bank of supercomputers to parse all of the information in real time. But with the right setup, you could probably see her, set off the alarm, and start to run facial recognition before she traveled more than a few meters.

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