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Satellites Taking Pictures of Rockets Carrying More Satellites

planet.com

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Re: Satellites Taking Pictures of Rockets Carrying More Satellites

#5
post #2

Would love to see an actual speed version of this... what's the hurry?

I presume their satellites aren't equipped to take more than one image per second. (For most of their applications, it's not necessary, and adding that ability to a microsat is would definitely increase the weight/cost/power.)

You can watch it on 25% speed on YouTube. It's pretty jittery, so it would be nice if someone made an interpolated version.

Re: Satellites Taking Pictures of Rockets Carrying More Satellites

#6
post #2

Would love to see an actual speed version of this... what's the hurry?

I presume their satellites aren't equipped to take more than one image per second. (For most of their applications, it's not necessary, and adding that ability to a microsat is would definitely increase the weight/cost/power.) You can watch it on 25% speed on YouTube. It's pretty jittery, so it would be nice if someone made an interpolated version.

I tried using butterflow and it seems ok at first, but I guess the algo is not made for this weird shot.

https://www.youtube.com/watch?v=8a6QoKQNGWA&feature=youtu.be

This one might be better.

FPS is set to 60 and speed is the same:

https://youtu.be/b7Ua4mXO23E

Re: Satellites Taking Pictures of Rockets Carrying More Satellites

#7
post #2

Would love to see an actual speed version of this... what's the hurry?

Think about the system[1], you've got to take a picture, store it, and then downlink it. If you take too many pictures your downlink is overloaded and you run out of memory. Assuming that an HD frame is about 2 megabytes once it is compressed, that is a 2 - 5 mbs downlink speed (depending on error correction). The satellites they launch are tiny and low power so they will have a limited budget for down link bandwidth.

That said, it makes me wonder about things like NROL76 which was a classified DoD payload that SpaceX launched and had no upper stage video from. At what point are there so many of these tiny satellites in orbit that they can pick up the fairing deploy and satellite separation independently? Or have them watch the X37 as it maneuvers around in orbit?

[1] https://www.planet.com/company/approach/

Re: Satellites Taking Pictures of Rockets Carrying More Satellites

#8
post #7
post #2

Would love to see an actual speed version of this... what's the hurry?

Think about the system[1], you've got to take a picture, store it, and then downlink it. If you take too many pictures your downlink is overloaded and you run out of memory. Assuming that an HD frame is about 2 megabytes once it is compressed, that is a 2 - 5 mbs downlink speed (depending on error correction). The satellites they launch are tiny and low power so they will have a limited budget for down link bandwidth…

If bandwidth were the main limiting factor, they would just take video intermittently and downlink it over a long period of time. This would be useful for documenting real-time changes on the ground during important isolated events (e.g., rocket launches). But they apparently don't have this capability, and I think it's because the hardware for taking many frames per second just isn't worth the cost and complexity.

Re: Satellites Taking Pictures of Rockets Carrying More Satellites

#9
post #2

Would love to see an actual speed version of this... what's the hurry?

I presume their satellites aren't equipped to take more than one image per second. (For most of their applications, it's not necessary, and adding that ability to a microsat is would definitely increase the weight/cost/power.) You can watch it on 25% speed on YouTube. It's pretty jittery, so it would be nice if someone made an interpolated version.

Their satellites have a one dimensional sensor that scans continuously.

Re: Satellites Taking Pictures of Rockets Carrying More Satellites

#10

Earlier quoted context omitted.

I presume their satellites aren't equipped to take more than one image per second. (For most of their applications, it's not necessary, and adding that ability to a microsat is would definitely increase the weight/cost/power.) You can watch it on 25% speed on YouTube. It's pretty jittery, so it would be nice if someone made an interpolated version.

Their satellites have a one dimensional sensor that scans continuously.

They are using 2D TDI CCDs, just like everyone else.

This timelapse was likely shot with frame by frame exposures though. I'm not sure how it's possible with TDI.

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