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41 votes
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Can a military satellite be used to spy on any place on Earth undetected?

Can the military use a military satellite to spy on any place on Earth? Yes, but only in the absence of clouds. The highest resolution imagery is only available during the day. I strongly suspect ...
gerrit's user avatar
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41 votes
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Why is this Planet Labs video wobbly?

Don't look at this from the perspective of why this was so lousy. Look at it from the perspective why this is so good. I thought Earth-observing satellites need to be extremely stable to provide a ...
David Hammen's user avatar
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34 votes
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Why did the KH-11 get the nickname "Kennen"?

From the National Reconnaissance Office website:
Organic Marble's user avatar
28 votes

Is there a satellite that tracks other satellites?

Tracking satellites and debris requires very powerful radar stations connected to extremely powerful computers on the ground, which can be augmented by some optical satellite technology. Trying to ...
GdD's user avatar
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28 votes

Could a spy satellite in orbit be recommissioned to do astronomy?

Surprisingly, yes, in at least a few limited cases. There are aspects of astronomy that could be done by pointing a spy satellite at solar-system objects besides the Earth. As any photographer will ...
uhoh's user avatar
  • 149k
26 votes

Could a spy satellite in orbit be recommissioned to do astronomy?

Spy satellites are used to look at a really bright object: daytime Earth. This needs short exposure times, detector noise is no problem, and you want a B/W or full-color image. Astronomical ...
Hobbes's user avatar
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24 votes
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When was it publicly revealed that a KH-11 spy satellite took pictures of the first Shuttle flight?

This was revealed in 2015, in the book Into the Black, about STS-1. The hardcover edition of Into the Black had the overall basics of the imaging effort, although not specific details. ... His new ...
Hobbes's user avatar
  • 128k
21 votes

Could a spy satellite in orbit be recommissioned to do astronomy?

Yes! Gamma-ray bursts from deep space were actually first discovered by the VELA spy satellites looking for hidden nuclear tests. The original 1973 paper Observations of Gamma-Ray Bursts of Cosmic ...
Nicole Sharp's user avatar
18 votes

Is there a satellite that tracks other satellites?

There are at least a few space based sensors, although I'm having some real difficulty getting more details about them. This article mentions them in particular. It seems these sensors are known as ...
PearsonArtPhoto's user avatar
  • 121k
17 votes

Can a military satellite be used to spy on any place on Earth undetected?

With respect to item 3, blurring photos - yes this happens. It does not however happen through cloaking technology but rather more boringly by various organizations requesting it of either the company ...
GremlinWranger's user avatar
14 votes
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Why are spy satellites in elliptical orbits?

This is just an educated guess; I'm not connected with the National Geospatial-Intelligence Agency, or any related agency. Europe is in the northern hemisphere, as is the Middle East and all of ...
David Hammen's user avatar
  • 74.9k
12 votes

Why is this Planet Labs video wobbly?

This is very likely the satellite's attitude control. If the satellite is not controlled, it will not just remain in its current orientation, but instead will at least rotate slowly. Maybe the solar ...
Hans's user avatar
  • 3,566
8 votes

Reconnaissance satellite altitudes

Reconnaisance satellites are at similar altitudes to the ISS. The ISS is at 330-400 km, recon sats are in elliptical orbits with a perigee on the order of 250 km. The big difference is the optics. ...
Hobbes's user avatar
  • 128k
8 votes

Is there a satellite that tracks other satellites?

The Tracking and Data Relay Satellite System (TDRSS) (unsurprisingly given its name) provides tracking. But, perhaps in a different sense that the other answers are discussing. TDRSS provides co-...
Organic Marble's user avatar
8 votes

Can a military satellite be used to spy on any place on Earth undetected?

To answer question number 2. There's actually a cottage industry among civilians to document and track spy satellites. Here is a link with some more information about one such organization: Meet the ...
Aaargh Zombies's user avatar
8 votes

Can a military satellite be used to spy on any place on Earth undetected?

One surprising aspect of satellite imagery is that sometimes you can "see" things that are not there! In regions of strong sunlight vehicles and aircraft on the ground leave cool shadows ...
BradV's user avatar
  • 3,292
7 votes

Is there a database of recent satellite images which will allow me to estimate how much of Mariopol has been destroyed?

Not a link to visual imagery but a very useful tool for the current situation: NASA's Fire Information for Resource Management System shows fires everywhere in the world with ~250-500 meter/6 hour ...
Alex Hajnal's user avatar
  • 1,981
7 votes

Is there a database of recent satellite images which will allow me to estimate how much of Mariopol has been destroyed?

MAXAR subsidiary DigitalGlobe has a web interface tool for viewing very up to date imagery. It is searchable by area, cloud cover, date, sun angle, and off nadir pointing angle (obliquity). Here is an ...
BrendanLuke15's user avatar
7 votes
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Can image-stacking allow this 0.25 m satellite telescope achieve 0.65m resolution?

The technique is known as "Super Resolution". Basically this involves a few steps, which the general outline is as follows: Knowing the point source performance to a sub-pixel level of your system. ...
PearsonArtPhoto's user avatar
  • 121k
6 votes
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What makes Gaofen-4 "the most powerful GEO spy satellite"?

To public knowledge, it is the highest-resolution imager in GEO. The 2nd place is occupied by weather sats with instruments like GOCI (https://en.wikipedia.org/wiki/Geostationary_Ocean_Color_Imager), ...
gosnold's user avatar
  • 1,298
6 votes
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Does a country need to announce the parameters of its newly launched satellite to the world?

No, they don't need to, but the UN requests that a country report their spacecraft. Personally, I suspect that many spy satellites are reported and tracked, except that the true nature of their ...
cubetronic's user avatar
5 votes
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Why is the LROC lunar data not showing farside of the moon?

You have to select the correct projection to see the far side of the Moon: It is the top tab in the side bar.
BrendanLuke15's user avatar
5 votes

Could DOD earth observation (i.e. spy) satellites have photographed the Columbia Orbiter on STS-107?

My comment referred to ground-based assets as well as satellites. Note that capabilities of such assets are highly classified. Some references can be found in the CAIB Report Part 2 which is devoted ...
Organic Marble's user avatar
5 votes
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Atmospheric influences on earth to satellite visibility and vice versa (e.g. atmospheric seeing)

Yes there is. The foggy window is much closer to the ground than to the orbiting satellite. Atmospheric turbulence takes place between 0 and 20km high, and satellites orbit over 200km high. To give ...
gosnold's user avatar
  • 1,298
5 votes
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Reconnaissance satellite altitudes

That's a great question! So your question is: why are images taken from observation satellites much better than the typical images of the ISS taken from the ground. The answer is: observation ...
gosnold's user avatar
  • 1,298
5 votes

Does the name "corona discharge" bear any relation to the Corona surveillance satellites or is this a coincidence?

It was a coincidence. The program was named Corona before the launch of the first satellite, so before the corona effect was ever seen on the recovered films. Secret projects like the Corona ...
Hobbes's user avatar
  • 128k
4 votes
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Any news about the Mars-3 landing site since early 2013?

The 2013 images and analysis are the most recent and the conclusion still stands - the features identified are likely to be the Mars-3 lander. NASA agrees with the conclusion as outlined in the above ...
Jack's user avatar
  • 9,956
3 votes

Is there a database of recent satellite images which will allow me to estimate how much of Mariopol has been destroyed?

Those databases exist, but they're generally not publicly accessible. There are basically two types of Earth observation data: from agencies (ESA, NASA, JAXA, etc.) and from private companies (Maxar, ...
Ludo's user avatar
  • 14.4k
3 votes

Atmospheric influences on earth to satellite visibility and vice versa (e.g. atmospheric seeing)

Atmospheric effects are mostly confined to altitudes where there is appreciable -er- atmosphere. Say below 100,000 feet (nonlinear, so probably 50,000 feet or less is where most turbulence occurs). ...
BobT's user avatar
  • 1,221

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