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Planet: Imaging the entire Earth every day

nbremer.github.io

131–140 of 144 posts

Re: Planet: Imaging the entire Earth every day

#131
post #124

Earlier quoted context omitted.

(I used to work at planet, this is my recollection of what was the case then) Usually, for ocean-sized bodies of water, we'd stop imaging entirely to reduce power load and align the solar panels with the sun. Effectively all of the ocean had nothing going on on the surface that we could image anyway. When Planet gets the imagery, they have a fairly good sense of where it is, but it is still processed to get it to ali…

You could track container ships, in fact they're probably so easy to detect you could run a small computer vision model on the satellite and only transmit those photos. Obviously the most interesting container ships are the ones that you can see from space but don't show up on marine trackers. Although I don't know how you turn that information into money. Actually someone must already be doing this, Airbus sponsored…

You could possibly spot container ships at one instance in a day (the constellation only goes over any point twice a day, ~10.30 AM (local) and 12 hours later (no sunlight)). To what end? You are roughly tripling your power, data storage, and downlink costs, with a loss on your power production (and orbit control, because the Doves use differential drag for phasing) for a poor product that doesn't really have customers.

If you want to track ships that want to be seen, basically everybody has AIS receivers up there (although I understand that's not trivial to sort out from space). If you want to track ships that aren't broadcasting, use radar.

Re: Planet: Imaging the entire Earth every day

#132
post #66

Earlier quoted context omitted.

It's called anthropogenic clouds, and it's possible but requires certain weather conditions to work: you need a source of water vapor that can saturate the air, and a stream of cold air to condensate that vapor. Then it's possible to launch particles into the air that would act as cloud condensation nucleus, and in theory it should start the cloud formation. Anyway, to hide a small area much easier solution would be…

The more common approach is using a large roof, and after that to build where it is usually cloudy.

Yeah, you cant expect privacy sunbathing nude on your own property in 2019.

Kinda scary.

Re: Planet: Imaging the entire Earth every day

#133
post #127

Earlier quoted context omitted.

I don't think that has anything to do with field of view. It's just that higher res = higher cost so they can't afford to have high res global coverage at LEO.

It really does have a lot do do with field of view. High res satellites fundamentally can't image a very large area (that's how a telescope works). They also usually can't image continuously. (High res means you can't image at the rate you're moving without significant SNR drawbacks - you have to stay pointed the target so that you have a long enough exposure time. You can get around this to some degree, but either w…

To emphasize on this: WorldView 4, which has ~31cm pan imagery came to a cost of about $850M. And is the size of a school bus. Vs the significantly smaller and less expensive stalites Planet uses. And unfortunately that stallite had a failur and only was usable for a bit over 2 years. High res satellites are really hard still.

Re: Planet: Imaging the entire Earth every day

#134
post #130

Really cool visualization! Talking about visualizing Earth. Does anyone know of alternative visualizations/projections of Earth (other than globes and maps)? For example, what would it look like if we could image Earth, entirely, from pole to pole, continuously, like a panoramic picture? (imagine the result as an impossibly wide picture that starts with one pole on the left and ends with the opposite pole on the righ…

I don't think that this is exactly what you're asking for, but you can explore most "standard" projections below (definitely try out the first link described below):

- Take a look at [0], click "Earth" in the lower left corner, then try other projections (they appear as the "A", "CE", "E", etc. list). Drag the map around to set the projection's "center". The real time projection calculations are pretty amazing..!

- Go to [1] and toggle all of the categories ("Wall Maps", "Maps of Hemispheres", etc.) by clicking them. The maps are not dynamic / cannot be dragged around (like [0]), but this is a more complete reference list (similar to Wikipedia's list of map projections [2]). The rest of the site is also absolutely incredible (I recommend taking ~1 hour to go through the whole list of projects one by one).

[0] https://earth.nullschool.net/

[1] http://www.radicalcartography.net/index.html?projectionref

[2] https://en.wikipedia.org/wiki/List_of_map_projections

Re: Planet: Imaging the entire Earth every day

#135
post #86
post #27

"Omega tau" made a really nice podcast a while ago about how Planet Labs is approaching Earth observation. That podcast goes into the details how the company and the satellite constellation came to be and what novel approaches they're using. Definitely worth listening: http://omegataupodcast.net/204-earth-observation-at-planet-l...

This is fascinating - especially the talks about the advantages of using COTS electronics. Once upon a time, the latest and greatest in electronics was produced by military, scientific, and spaceflight applications, with commercial uses being spinoffs that were often up to a decade behind. Now the situation is reversed; consumer electronics are where the innovation is happening, and military/space systems are finding…

I think this is only true for small LEO spacecrafts that are more or less 'disposable'. For higher cost GEO and interplanetary spacecraft, consumer electronics are not going to be hardened sufficiently and flight-proven to be used in those applications.

Re: Planet: Imaging the entire Earth every day

#136
post #86

Earlier quoted context omitted.

This is fascinating - especially the talks about the advantages of using COTS electronics. Once upon a time, the latest and greatest in electronics was produced by military, scientific, and spaceflight applications, with commercial uses being spinoffs that were often up to a decade behind. Now the situation is reversed; consumer electronics are where the innovation is happening, and military/space systems are finding…

I think this is only true for small LEO spacecrafts that are more or less 'disposable'. For higher cost GEO and interplanetary spacecraft, consumer electronics are not going to be hardened sufficiently and flight-proven to be used in those applications.

Isn't really about those being higher cost - as the Planet people say, their approach is only possible because they're working inside Earth's magnetosphere.

Re: Planet: Imaging the entire Earth every day

#137

Earlier quoted context omitted.

I think this is only true for small LEO spacecrafts that are more or less 'disposable'. For higher cost GEO and interplanetary spacecraft, consumer electronics are not going to be hardened sufficiently and flight-proven to be used in those applications.

Isn't really about those being higher cost - as the Planet people say, their approach is only possible because they're working inside Earth's magnetosphere.

They also mentioned that they can afford to have satellites fail since they are cheaper and sending up so many. Also won't be possible with one-off GEO birds.

Re: Planet: Imaging the entire Earth every day

#139
post #51

Earlier quoted context omitted.

If you could track the satellite could you not shine a laser, or bright light (maybe a mirror reflecting the sun) directly at the camera to mess up the imaging while over your region?

This would simply make it very obvious that you are investing substantial resources trying to obscure a location.

Might be fine if all you want is to feel free in your own garden (nude is a common example, but also clothed, if you feel like you might be observed at any time...).

Re: Planet: Imaging the entire Earth every day

#140
I do not see daily updates on planet.com, at least for the free trial account I just created, and for my location (Eastern Europe).

For example, there is a damb nearby which was completed a few months ago, but is shown half-built in their map.

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