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Roscosmos has shared before & after satellite imagery for anyone interested: https://twitter.com/roscosmos/status/1291023063404994560/photo/1 https://twitter.co

Roscosmos has shared before & after satellite imagery for anyone interested: https://twitter.com/roscosmos/status/1291023063404994560/photo/1 https://twitter.com/roscosmos/status/1291023063404994560/pho...

deadalus 6y ago
Regarding the satellite image, a few questions : 1) Can nation-states spy like this on every location on the planet? 2) Can you view the live feed of any location and follow vehicles(for example)? 3) Is there anything a country can do to prevent other's from spying on your country from satellites?
- _jal 6y ago
  1) Yes. 2) Well, I can't, but the capability exists. 3) Dig.
- taejo 6y ago
  I don't think you can get a live feed of a location since the satellites generally aren't geostationary (geostationary orbit is too far away, and are always above the equator). But AFAIK even commercially you can get still photographs of any point on earth within a couple days (i.e. you don't have to be a nation state or have your own satellites)
  - walrus01 6y ago
    a live feed to follow something would 99% of the time be implemented from a HALE (high altitude/long endurance) group 4 size UAS. RQ9 or in the same class, with a combination of a high end gimbaled camera system and satellite data uplink.
  - savoytruffle 6y ago
    Geostationary is very very far away and useless for nighttime. Imaging satellites usually have a shorter polar orbit that precesses east to west along with sunshine. https://en.wikipedia.org/wiki/Sun-synchronous_orbit https://en.wikipedia.org/wiki/Sun-synchronous_orbit
- htrp 6y ago
  2) costs lots of money, or you have to be a government. following vehicles is near impossible commercially (resolutions are too low)
- azernik 6y ago
  1. Yes. Not just state actors - Planet Labs (https://www.planet.com/ https://www.planet.com/) in San Francisco, for example, is a commercial satellite company that photographs the whole globe once per day and sells that imagery online. 2. Live feed is a bit tricky, and that's where governments have an advantage - they own their own satellites, and can task them to follow a specific target. But you have to know where the target is at the start of the window, they don't have real-time video of the whole planet, and unless you've got a very big fleet you won't always have a satellite overhead when you want to look at your target. 3. Keeping track of the times of satellite passes overhead, hiding stuff underground, putting your aircraft in covered hangars and only moving them at night, putting a roof on your military docks, using upwards-facing camouflage, etc. Same methods that have been used for a hundred years to hide from air surveillance.
  - DuskStar 6y ago
    > 2. Live feed is a bit tricky, and that's where governments have an advantage - they own their own satellites, and can task them to follow a specific target. But you have to know where the target is at the start of the window, they don't have real-time video of the whole planet, and unless you've got a very big fleet you won't always have a satellite overhead when you want to look at your target. I would really not be surprised to see the NRO go the Planet Labs / Starlink route at some point in the future and put 20 satellites in a dozen orbital planes to provide coverage everywhere at less than 60 degrees latitude 24/7/365. Sure, maybe you need the big KH-11s for the extremely high resolution shots - but 3m resolution isn't exactly trash either.
    - ta17711771 6y ago
      > unless you've got a very big fleet Starlink
    - azernik 6y ago
      At 3m resolution a tank is about 3 pixels; a sedan is around 1 pixel. It's very hard to distinguish objects from each other and therefore to track one at that resolution.
  - 6y ago
- TallGuyShort 6y ago
  2) is more of a drone thing
  - gizmo686 6y ago
    Drones require you to get permission or vioalate the airspace of the host country.
    - Scoundreller 6y ago
      Or a good relationship with your neighbours or a target close to international waters. What’s a dozen extra kilometres when you’re that high anyway.
- numpad0 6y ago
  Satellites fly unpowered and frictionless in the vacuum, with kinetic energy equivalent to speed of Mach 22 at sea level, balancing against Earth’s gravitational pull, along an own 2D ellipse with one focus at the center of the gravity of the Earth. So you can’t like fly a 3D orbit, fly at same altitude but different angular velocity, or change course without expelling significant amounts of mass. You play by those rules.
pmarreck 6y ago
Jesus, it left a CRATER!
- hackermailman 6y ago
  Look how much there was in that warehouse https://cdn.ren.tv/cache/960x540/media/img/26/fb/26fb305fdd5080135e3c1c9a51f8f2930a6d5585.JPG https://cdn.ren.tv/cache/960x540/media/img/26/fb/26fb305fdd5... this was all on Ukrainian tv years ago when the crew was stranded there
- weinzierl 6y ago
  The 800 tons of Ammonium Nitrate that exploded in Tianjin in 2015 left a 100 meter wide crater. In Beirut it was 2750 tons, almost three and a half times as much.
- dmix 6y ago
  Land reclamation.
tyingq 6y ago
Looks like it was pretty fortunate to have been in that warehouse versus further back. A pretty good amount of the direct blast radius looks like it was water.
raghava 6y ago
"Before" is dated 2019. All the diff is to be atrributed to this blast? Am I missing anything obvious here?
- wodenokoto 6y ago
  Sibling has posted a link to a higher res version from a different source. I think the before there is closer in time. The structure to the far left on parents before picture is apparently removed before the explosion.
kornholi 6y ago
Higher res imagery from Planet: https://twitter.com/planetlabs/status/1291010972983992320 https://twitter.com/planetlabs/status/1291010972983992320
- eternalban 6y ago
  If you zoom in on the highways, you can see RGB ghost images of moving vehicles. Is that an artefact of using 3 distinct filtered inputs or something else? [ps. The frequency shift is definitely reflecting vehicle direction - right side of highway is BGR, the other side is RGB. Delays in the sequence of 3 filtered captures?]
  - kornholi 6y ago
    Yes, the different bands are not collected at the same time across the whole scene, so you get ghosting with moving objects. The SkySat sensor [1] is split in two halves: panchromatic and RGBN (where N is near-infrared). It takes lots of captures as the satellite travels that are later aligned and combined into one version. [1] https://directory.eoportal.org/documents/163813/5615117/SkySat_Auto8.jpeg https://directory.eoportal.org/documents/163813/5615117/SkyS...

deadalus 6y ago

Regarding the satellite image, a few questions : 1) Can nation-states spy like this on every location on the planet? 2) Can you view the live feed of any location and follow vehicles(for example)? 3) Is there anything a country can do to prevent other's from spying on your country from satellites?

_jal 6y ago
1) Yes. 2) Well, I can't, but the capability exists. 3) Dig.
taejo 6y ago
I don't think you can get a live feed of a location since the satellites generally aren't geostationary (geostationary orbit is too far away, and are always above the equator). But AFAIK even commercially you can get still photographs of any point on earth within a couple days (i.e. you don't have to be a nation state or have your own satellites)
- walrus01 6y ago
  a live feed to follow something would 99% of the time be implemented from a HALE (high altitude/long endurance) group 4 size UAS. RQ9 or in the same class, with a combination of a high end gimbaled camera system and satellite data uplink.
- savoytruffle 6y ago
  Geostationary is very very far away and useless for nighttime. Imaging satellites usually have a shorter polar orbit that precesses east to west along with sunshine. https://en.wikipedia.org/wiki/Sun-synchronous_orbit https://en.wikipedia.org/wiki/Sun-synchronous_orbit
htrp 6y ago
2) costs lots of money, or you have to be a government. following vehicles is near impossible commercially (resolutions are too low)
azernik 6y ago
1. Yes. Not just state actors - Planet Labs (https://www.planet.com/ https://www.planet.com/) in San Francisco, for example, is a commercial satellite company that photographs the whole globe once per day and sells that imagery online. 2. Live feed is a bit tricky, and that's where governments have an advantage - they own their own satellites, and can task them to follow a specific target. But you have to know where the target is at the start of the window, they don't have real-time video of the whole planet, and unless you've got a very big fleet you won't always have a satellite overhead when you want to look at your target. 3. Keeping track of the times of satellite passes overhead, hiding stuff underground, putting your aircraft in covered hangars and only moving them at night, putting a roof on your military docks, using upwards-facing camouflage, etc. Same methods that have been used for a hundred years to hide from air surveillance.
- DuskStar 6y ago
  > 2. Live feed is a bit tricky, and that's where governments have an advantage - they own their own satellites, and can task them to follow a specific target. But you have to know where the target is at the start of the window, they don't have real-time video of the whole planet, and unless you've got a very big fleet you won't always have a satellite overhead when you want to look at your target. I would really not be surprised to see the NRO go the Planet Labs / Starlink route at some point in the future and put 20 satellites in a dozen orbital planes to provide coverage everywhere at less than 60 degrees latitude 24/7/365. Sure, maybe you need the big KH-11s for the extremely high resolution shots - but 3m resolution isn't exactly trash either.
  - ta17711771 6y ago
    > unless you've got a very big fleet Starlink
  - azernik 6y ago
    At 3m resolution a tank is about 3 pixels; a sedan is around 1 pixel. It's very hard to distinguish objects from each other and therefore to track one at that resolution.
- 6y ago
TallGuyShort 6y ago
2) is more of a drone thing
- gizmo686 6y ago
  Drones require you to get permission or vioalate the airspace of the host country.
  - Scoundreller 6y ago
    Or a good relationship with your neighbours or a target close to international waters. What’s a dozen extra kilometres when you’re that high anyway.
numpad0 6y ago
Satellites fly unpowered and frictionless in the vacuum, with kinetic energy equivalent to speed of Mach 22 at sea level, balancing against Earth’s gravitational pull, along an own 2D ellipse with one focus at the center of the gravity of the Earth. So you can’t like fly a 3D orbit, fly at same altitude but different angular velocity, or change course without expelling significant amounts of mass. You play by those rules.

pmarreck 6y ago

Jesus, it left a CRATER!

hackermailman 6y ago
Look how much there was in that warehouse https://cdn.ren.tv/cache/960x540/media/img/26/fb/26fb305fdd5080135e3c1c9a51f8f2930a6d5585.JPG https://cdn.ren.tv/cache/960x540/media/img/26/fb/26fb305fdd5... this was all on Ukrainian tv years ago when the crew was stranded there
weinzierl 6y ago
The 800 tons of Ammonium Nitrate that exploded in Tianjin in 2015 left a 100 meter wide crater. In Beirut it was 2750 tons, almost three and a half times as much.
dmix 6y ago
Land reclamation.

tyingq 6y ago

Looks like it was pretty fortunate to have been in that warehouse versus further back. A pretty good amount of the direct blast radius looks like it was water.

raghava 6y ago

"Before" is dated 2019. All the diff is to be atrributed to this blast? Am I missing anything obvious here?

wodenokoto 6y ago
Sibling has posted a link to a higher res version from a different source. I think the before there is closer in time. The structure to the far left on parents before picture is apparently removed before the explosion.

kornholi 6y ago

Higher res imagery from Planet: https://twitter.com/planetlabs/status/1291010972983992320 https://twitter.com/planetlabs/status/1291010972983992320

eternalban 6y ago
If you zoom in on the highways, you can see RGB ghost images of moving vehicles. Is that an artefact of using 3 distinct filtered inputs or something else? [ps. The frequency shift is definitely reflecting vehicle direction - right side of highway is BGR, the other side is RGB. Delays in the sequence of 3 filtered captures?]
- kornholi 6y ago
  Yes, the different bands are not collected at the same time across the whole scene, so you get ghosting with moving objects. The SkySat sensor [1] is split in two halves: panchromatic and RGBN (where N is near-infrared). It takes lots of captures as the satellite travels that are later aligned and combined into one version. [1] https://directory.eoportal.org/documents/163813/5615117/SkySat_Auto8.jpeg https://directory.eoportal.org/documents/163813/5615117/SkyS...