[d_silin]

The bandwidth is not expensive. There is simply a lack of it.

Most LEO satellites have 10-20 minutes a day communications window assuming single ground station. Amount of data you can download from a single pass is a tens or hundreds megabytes per day. One high-resolution camera image can be easily over 10MB.

[portyllo]

There is plenty of bandwidth to achieve more than 1 Gbps of throughput from a 3-U cubesat (see Planet with their latest X-band comms-system [1], which results in more than 50 GB per pass). If you really need more than that, new free space optical communications systems under-development will bring multi-Gbps to small-sats [2]. For me, the real problem with nanosats is that they generate barely no power and they are really volume-constrained compared to the bigger birds (so you cannot have high-resolution sensors, and cannot fit in there a good optical-comms system, you need to be mindful of your power consumption all time during the mission...).

Finally, note that nowadays Planet downloads 10 TB/day, and they could go up to 40 TB/day once they upgrade their fleet with the latest X-band antenna, which is comparable to the 80 TB/day that DigitalGlobe generates.

[1] https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=4... [2] https://www.tesat.de/images/tesat/products/TOSIRIS_Data-Shee...

[lozaning]

Very interesting, thanks for the follow up.

Would this issue be any way relieved with things like AWS ground station?

If you can only see a ground station from a satellite for 20 minutes, could you just add more ground stations?

Or is that 20 minutes window constrained by something other than having a ground station within receiving range?

[d_silin]

More ground stations will definitely make things better, but 24/7 connectivity to assets in LEO will take monumental, Starlink-scale level of effort.

[portillo]

You can get 24/7 connectivity to LEO right now (and 25 years ago too) using TDRSS.

The system costs a fraction of what Starlink will cost, as you only need 3 GEO satellites.

[chinathrow]

Would it be possible to use Starlink for comms if a sat is flying in a lower position?

[d_silin]

In theory, yes.

In practice, this will depend more on my negotiation skills when talking to Elon Musk and less on any technical challenge :)

[portyllo]

No, it will not be possible, no matter what Elon says.

Starlink operates in portions of the Ku and Ka bands that are reserved for Earth-to-space comms, not for space-to-space comms.

[d_silin]

My impression was that Starlink relies on inter-satellite links to route traffic. We can use the same links for our own extended network.