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I came up with a world that is similar to ours but is recovering from oil reserves depletion. In other words, there is very little to no petrol remaining, so the ones who can use it are mostly military. The idea is that crisis has already passed and the world is no longer on the verge of the hunger-disease-anarchy-based abyss. It is not a post-apocalyptic world, but rather very beaten up. Many countries are still standing, but there is a lot of aftermaths to deal with. Technology is just a little better than today.

The focus of the story that I am trying to develop is on a before-crisis oil rig. In this setting, as one can imagine, there was a period when it was worth equipping these oil rigs with numerous crews, the latest pieces of technology, and build them huge with an ability to move on their own. So they are basically little cities that had their own little ecosystems that were supplied from land. Later all of them were abandoned and some of them were left in the ocean.

enter image description here

Then after some time passed somebody found this oil rig and started doing some international crimes like human and drug trafficking.

How effective will be an attempt to find this oil rig via satellite? And with effective, I mean some bounds of how much time it may take.

Let the number of countries that are willing to spend their time to search for this platform be a free variable in this question.

To make up for the hard science tag I will provide some numbers and additional info if somebody needs it for an answer:

  • oil rig will fit in 1 kilometer squared
  • it will not fit in an area of 100m by 100m
  • There is jet fuel for jets but their use is very limited
  • Technology is almost similar to today's ones.

Feel free to request the information about the world, but you safely can assume that is it similar to our's with the exception that everything is running on electricity and a huge crisis just passed by.

PS. I know that there are more convenient ways to find this station, but I want to know how likely it is to succeed using satellites under hard science constraints.

EDIT: Some answers are concentrating on satellite camera resolution. It is an important factor, but my question is more about the ground coverage. I think it is safe to assume that if somebody caught it on tape it is possible to find a rig there. (Given that data from satellite is processed within less than a week after being taken)

EDITEDIT:

I found a useful link that can help somebody later. After link will be dead:

  • They are called "Dark ships"
  • Important technology is "Space-based radio frequency (RF) mapping"

Also, there are some articles(one and two) about GF-4 satellite which is relatively new. Its purpose is to track ships, but it is on GSO, so no scanning is possible. It is covering the "7000 km x7000 km" area which is very big.

enter image description here

It is possible to zoom up in minutes to 400kmx400km scene and take very detailed pictures(up to less the 100m resolution). With this in mind, the remaining question is its ability to scan the ocean. Because if it can change a scene in minutes it can scan all its field of view in:

  • scenes in ocean: $\left(\frac{7000km}{400km}\right)^2 = 306.25$
  • if 0.25 is a scan rate in scenes per minute, then the whole ocean is scanned within $\frac{300}{0.25} \approx 1200 \text{ minutes} \approx 1 \text{ day}$

Thus the station is found in days, crime is punished, no pirate state in my story. Very sad :( Thanks for coming to my talk.

CLOSING:

As I found the answer - I will close the question in a few days or maybe I will extract the answer and mark the question as answered one.

Or you may post something that will help to make the pirate state possible

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    $\begingroup$ How many "spy" satellites are in this world? Also, this self-propelling rig will be very slow - any half-decent sailboat will outpace it. $\endgroup$
    – Alexander
    Aug 14, 2021 at 2:51
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    $\begingroup$ Radar satellites to detect and track naval vessels have been around for decades now. See, for example, en.m.wikipedia.org/wiki/US-A $\endgroup$
    – Jon Custer
    Aug 14, 2021 at 3:03
  • $\begingroup$ Finding one of these from the air would be pretty straightforward, so why from space ? Fueling a plane would be a great deal easier than fueling a rocket to space (which requires enormous amounts of propellant and resources) and we're already starting to develop hydrogen powered aircraft, and there is the possibility of using biofuels for planes (they don't have to be jets). $\endgroup$ Aug 14, 2021 at 4:57
  • $\begingroup$ @StephenG, if you will provide some math or sources I will really appreciate them. $\endgroup$
    – FrogOfJuly
    Aug 14, 2021 at 11:01
  • $\begingroup$ @Alexander, as one can imagine the speed is based on power source. If there is a reactor on the rig it may outspeed many boats in the world with no oil. As for settelites - there are not more than today. $\endgroup$
    – FrogOfJuly
    Aug 14, 2021 at 11:05

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We have no way of knowing the capabilities of military observation satellites but we can at least examine what commercial observation satellite services provide. Let's look at select quotes from https://www.technologyreview.com/2019/06/26/102931/satellites-threaten-privacy/

US federal regulations limit images taken by commercial satellites to a resolution of 25 centimeters, or about the length of a man’s shoe.

The implication is that because commercial satellites use the maximum permitted resolution currently and so can identify and even make out details on the rig if they find it.

The imaging company Planet Labs currently maintains 140 satellites, enough to pass over every place on Earth once a day.

The implication is that if the rig is stationary or slow moving, it can be recorded within one day (weather permitting) by a single commercial satellite imaging company. How fast it is actually found depends on how much effort is placed in analyzing the imagery but it isn't implausible to say that the processing would take less than a week; projects to find ships from satellite monitoring are underway to help find shipping and fishing vessels that are operating illegally.

In 2008, there were 150 Earth observation satellites in orbit; by [2019] there are 768.

The implication is that, in theory, in 2019 one could check every spot on earth 5 times a day if the commercial satellites were cooperating and arranged in the right way, making detection even faster.

Bonus commentary: Though it probably doesn't apply to the oil rig scenario, there is a wrinkle to detectablity of an object on the ocean. Each satellite has a limited field of view so only a very small part of Earth is visible to the combined set of satellites at any given instant. IF there are few enough satellites and IF a ship knows what the orbital patterns of the satellites are (they're hard to hide from ground based observations and can't change orbit easily because the fuel cost is high) and IF said ship can move fast enough and can afford the constant immense cost in fuel, it is possible for it to move in a pattern such that it is never in any satellite's field of view at any given time. This used to be possible for navies during the Cold War when there were few reconnaissance satellites but isn't practical anymore after satellite launches became relatively inexpensive.

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  • $\begingroup$ Do you have any sources about that hiding thing you mentioned? $\endgroup$
    – FrogOfJuly
    Aug 14, 2021 at 10:48
  • $\begingroup$ @FrogOfJuly I haven't been able to find where I read it unfortunately. There is some indirect evidence from Table 4 of "Staring at the Sea - The Soviet RORSAT and EORSAT Programmes" (asifsiddiqi.com/work/crystals-7cl9h) which gives hours between coverage passes at various latitudes and satellite counts. Though not the primary meaning of the table, those values can also be understood as the # of hours a ship has to cross a patch of ocean equal to the sensing area of a satellite before being spotted by the next satellite checking the same area. $\endgroup$ Aug 14, 2021 at 20:19
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Difficulty depends on how long you're willing to search

Earth's circumference is ~40,000 km. The ISS makes about 15.5 orbits in a day. That means that satellite orbiting at the same velocity trying to get total coverage of the Earth could do so with a 1,333* km ground swath. That's ~423x the 6.3 km ground swath quoted for the KH-8 Gambit mentioned in KEY_ABRADE's answer. That means that Gambit's camera could cover that the 1,333 km swath to a resolution of 21 meters. That would put the oil rig in the 100-1000 m range in a box of 5x5 - 47x47 pixels. Depending on how different in coloration the oil rig is from the surrounding sea, even a 5x5 box should be findable, and a 47x47 would be even easier.

And of course, the longer you're willing to spend in a full circumnavigation, the smaller your swath can be, and the higher your resolution.

Of course, if the rig runs dark at night, that halves your available searching time. On the other hand if it keeps its lights on then spotting it should be easy indeed.

NOTE: I've made a bunch of assumptions here for the sake of keeping the math easy. Even if they don't quite add up, a satellite that scans the Earth in a week or a month should still be reasonable. Of course, just because a satellite which scans like this could exist doesn't mean that there's presently an existing satellite which has that capability.


*A full orbit crosses the equator twice, so you need half the ground swath you might expect at first glance.

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  • $\begingroup$ I am not afraid of math, so if you have same calculations I will appreciate them. $\endgroup$
    – FrogOfJuly
    Aug 14, 2021 at 10:45
  • $\begingroup$ And another thing, as I understood KH-8 is a single use launch. So to make more coverage one need to launch more sattelites. On wiki it is said that there were 54 of them in ~20 years. It is poor rate of scanning if somebody want to find platform in the ocean $\endgroup$
    – FrogOfJuly
    Aug 14, 2021 at 11:17
  • $\begingroup$ @FrogOfJuly Oh, I wasn't trying to keep the math easy for you guys - I was trying to keep it easy for me. $\endgroup$ Aug 14, 2021 at 14:36
  • $\begingroup$ "Of course, if the rig runs dark at night, that halves your available searching time. " Assuming you limit your sensors to human visible light.... $\endgroup$
    – NPSF3000
    Aug 14, 2021 at 16:17
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    $\begingroup$ @NPSF3000 - alternatively, a rig that show up in your sensors with all the visible lights off isn't running dark, it's just trying to. But your point that a visible light camera might not be the most effective one for this job is a good one, though. $\endgroup$ Aug 14, 2021 at 18:17
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The KH-8 Gambit could resolve features smaller than 4 inches across - 9,842.51969 times smaller than the dimensions of this one-by-one-kilometer oil rig.

This is absolutely possible.

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    $\begingroup$ How many launches does it take to find the platform, though? It is said on Wikipedia that it is a "6.3 km wide ground swath". There are many of such swaths to choose from. So the resolution is good, but how does one find what to take a photo of? $\endgroup$
    – FrogOfJuly
    Aug 14, 2021 at 1:59
  • $\begingroup$ @FrogOfJuly My point is that modern camera technology makes this very much possible. It depends on the type of satellite we're talking about here. $\endgroup$
    – KEY_ABRADE
    Aug 14, 2021 at 4:13

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