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Is it possible to create a telescope in geostationary orbit, with real-time video from any country or area?

Some applications could be:

  • Monitoring of burning and deforestation;
  • Residential/industrial security
  • Rescues
  • Monitoring of plantations
  • Mapping and more...

If possible, what are the biggest challenges of the project? Technology, licenses or laws, costs?

(I'm new here, I hope I asked an interesting question :D)

Edit: I'm in love with this community! Thank you very much!

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    $\begingroup$ I dont know if cameras would qualify as telescopes, but, geo satellites with camera already exist. $\endgroup$
    – AJN
    Nov 7, 2021 at 4:50
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    $\begingroup$ I can't remember what it is right now, but there was (somewhat) recently deployed a big commercial communications satellite with a piggyback scientific Earth observation platform attached. It's certainly possible; but at 50 times farther than LEO you'll need a much bigger aperture for similar diffraction-limited resolution. Pointing is one big advantage, from LEO the Earth's surface's relative motion is ~7,000 m/s so you have to manage that by using a scanning camera or short exposures or slewing the scope or the satellite. From GEO the surface will appear almost motionless. $\endgroup$
    – uhoh
    Nov 7, 2021 at 5:44
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    $\begingroup$ found it! NASA's Global-scale Observations of the Limb and Disk or GOLD is piggybacked on SES-14 There are three research results papers in Geophysical Research Letters link to in [GOLD’s Top-Down View of Our Atmosphere ](blogs.nasa.gov/sunspot/2021/08/30/…). See also NASA Goddard's GOLD. $\endgroup$
    – uhoh
    Nov 7, 2021 at 7:12
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    $\begingroup$ I liked it! "GOLD's mission is to image the boundary between Earth and space" - So, I believe that creating a telescope similar to Hubble, configured for this distance and geo orbit can work, in order to take "sharp" images. I imagine one pointed to Brazil, it looks like the position would be good! $\endgroup$ Nov 7, 2021 at 14:41
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    $\begingroup$ Chinese Gaofen-4, India's GEO Imaging Satellite (GISAT)-1,2 are few examples of GEO based imaging satellites. Unfortunately GISAT-1 launch failed recently but India has a experimental Geo High Resolution Camera (GHRC) payloadon GSAT-29 satellite. That can image @~50m resolution @ ~0.6 sec/frame in six spectral bands. A video from it in here @ 20 sec mark onwards gfycat.com/dampbadhomalocephale and a paper researchgate.net/publication/… $\endgroup$
    – Ohsin
    Nov 7, 2021 at 18:06

3 Answers 3

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Is it possible to create a telescope in geostationary orbit, with real-time video from any country or area?

The big picture

The question lists several different applications. For deforestation (by logging, burning or anything else) or massive burning of fields before planting each year (also a huge problem in some parts of Asia) you don't need very high resolution.

In these cases you could monitor a very large area at modest resolution.

But these things take place with timescales of days or months, you would not need "video".

Zooming in on details, for "one billion dollars!":

enter image description here

enter image description here

If "area" can be a few dozen city blocks (and not a whole country) and you want to monitor details in real time for security reasons (e.g. a car parked outside a building) then it is also possible, but...

But it would have to be quite a large telescope if you want the same resolution you can get from low Earth orbit (LEO).

Above are GIFs showing relatively high resolution videos from LEO. These are taken from this answer to Hovering Carbonite! Why do these satellite videos of Earth appear to be made from a geostationary location? and the question contains the original videos shot from orbit at about 500 km.

I can't find the exact diameter of the aperture, but Spaceflight 101 says:

The baseline envelope for the SSTL-X50 platform is 65 x 65 x 72 centimeters and satellites using the platform weigh around 100 Kilograms at launch.

So I'll estimate the aperture at 20 cm. That's consistent with answers to

Carbonite 1

Carbonite 1 Source

Now, suppose you wanted to do that (maintain the same resolution at Earth) but now at an altitude of 35,786 kilometers rather than 500 kilometers?

0.2 meters times 35,786 / 500 suggests an aperture of 14 meters!

That's twice the diameter of JWST!

For reasons of launch mass you would need to make your mirror segments out of exotic materials rather than glass like many space telescopes:

and considering the JWST cost roughly ten billion dollars this would probably set you back at least one billion.


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    $\begingroup$ Excellent answer. Looking at it the other way: if you take that existing cheap platform to GEO distances, you would go from ~65cm resolution to ~900m resolution. $\endgroup$ Nov 8, 2021 at 12:51
  • $\begingroup$ Well, I would like to have both applications on the same instrument. Together with the problems mentioned by @Ng Ph, and the 14 meter aperture you mentioned, there really would be several "problems" to solve in a project of this level, but with new alternatives for mirrors, artificial intelligence for video processing, cheap launches with Spacex, and a few billion for dollars, seems to me madly viable. Thanks for the details, very nice! $\endgroup$ Nov 8, 2021 at 14:25
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    $\begingroup$ @theCrazySander Artificial intelligence doesn't help anything. It can create pictures that look good, but it can't provide accurate representations of missing detail. It's just a "best guess" that doesn't provide any further information. $\endgroup$
    – asdfex
    Nov 9, 2021 at 17:25
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    $\begingroup$ @uhoh look this channel youtu.be/ICr6xi9wA94?t=33 $\endgroup$ Nov 12, 2021 at 0:21
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    $\begingroup$ @theCrazySander removing foreground obscurations by processing several images where the foreground object (which is mostly open holes) moves across the field and the hidden parts are "painted" by AI" is not at all a technology that could increase the resolution beyond the diffraction limit. It simply generates "plausible guesses" assuming that the background object doesn't change. The whole point of pointing a camera at Earth is to see things that DO change, so this would give you exactly what you DON'T want. And it still won't improve resolution. $\endgroup$
    – uhoh
    Nov 12, 2021 at 0:34
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Going to take a really brief, "explain like I'm five" kind of answer here:

Is it possible to create a telescope in geostationary orbit, with real-time video from any country or area?

Yes, absolutely! Even better, you can see nearly an entire hemisphere of the Earth from geostationary orbit, so you can look at any place on almost half the planet whenever you want, just by turning your head (camera). Of course, you'll only be looking straight down at the spot you're right over, but that's not that big an issue.

If possible, what are the biggest challenges of the project? Technology, licenses or laws, costs?

None of those. Just distance. Geostationary orbit is really really really far away. It's a 10th of the way to the moon. There's limits on how finely you can resolve detail from far away using light. Why? Because the further away you get, the more dim the light reflecting from any one small detail is. You need a huge camera (like a physically wide lens) to collect enough of it to distinguish said detail from random noise.

Turns out it's easier to just have a bunch of smaller cameras in lower orbits that pass over your target than one HUGE one way up at geostationary orbit.

Of course, if you don't need to see in detail (for example, if you're trying to monitor forests or fields or hurricanes or something), GEO's quite fine for your purposes. There's many geostationary/geosynchronous earth-observing satellites. Probably some of the most famous ones are the big weather birds that NOAA has been building for decades. I believe many of the nuke-detecting satellites are also geostationary, but I'm too lazy to confirm this.

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I am afraid it doesn't make much sense, for the following reasons:

  • a telescope works in the optical domain. On Earth, it's angular resolution is limited by turbulences in the atmosphere (when it is not obstructed by clouds). Hence, putting a telescope in LEO (or MEO/GEO) to look at the stars makes sense. Putting it in GEO and turning it towards the Earth to look through the atmosphere (and clouds) is illogical.

  • any image capture works better when there is good constrast and moderate dynamic range. If you want to detect a faint star, better find a place with minimum light pollution. Try to avoid a brighter star in the same field of view. An image capture in GEO will have to mitigate for sun glaring most of the time and high dynamic range situations, unless it has mechanisms to drastically reduce the field of view. This narrow field of view is incompatible with the requirements of many applications (such as monitoring of large areas in real time), for which GEO orbits are preferred.

  • There are other sensors than telescope more suited for most of the applications you mention. Infrared for example can be used for wild fire detection (and ballistic missiles too). Meteosat satellites are another examples of how GEO orbits can be exploited for weather forecasting (seeing but not for seeing through the clouds). They have also payloads for detection of search-and-rescue signals. However, for geometrical reasons, their capability of pinpointing the location of the distress signals are not as good as that of constellation, as well as their detection of weak signals (due to distance).

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  • $\begingroup$ Very good! I was looking to find problems like that! Perhaps a good artificial intelligence and video processing system can solve most of the aforementioned problems, mixing other types of sensors etc. $\endgroup$ Nov 8, 2021 at 14:06
  • $\begingroup$ @theCrazySander, perhaps ... but be careful not to fall into the trap of "solutions in search of a problem". $\endgroup$
    – Ng Ph
    Nov 8, 2021 at 17:46

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