VegaLyrae

Oh boy, what can’t we put ads in?

Can we get MtDew Green Lights with Coca-Cola Red lights?

The spacebar on laptops is free game, just asking for it.

It really is a shame that I can still buy bedsheets that aren’t branded with a corporate advertising campaign.

Open source does not mean open license.

Yes, typically with two entirely separate disks, not just partitions on the same physical disk.

It is 5 minutes of work to use your source control tool, and have a read only view for other people.

Being open source doesn’t mean you have to accept PRs or pay for audits. It just means your source is… Open…

There’s nothing disingenuous about that? Did we read the same things?

Being closed source doesn’t fix any of the issues they noted.

I’d rather they just say “I’m ashamed of my code”.

I just commented this elsewhere, but I personally feel that their reasons for being closed source are worse than actually just being closed source.

https://obsidian.rocks/why-isnt-obsidian-open-source/

I wasn’t worried about it being proprietary until I saw the founder reasoning for not having the source be open under a nonpermissive licence.

https://obsidian.rocks/why-isnt-obsidian-open-source/

I decided to go with logseq because of it.

It also syncs with all my devices using my own servers, instead of needing to trust obsidian/logseq.

Who could have guessed that may-issue permits could be (gasp) abused!

I thought the police would be even and fair in their determination of who should get one, just like they are in all their other activities.

I am an engineer that has worked in the space industry my entire career, and here are my thoughts:

GOES and METEOR weather satellites transmit images publicly that are NOT real time, but are downlinked, processed, and uplinked for public broadcast. This is pretty simple and saves a lot of processing power on the spacecraft side. That’s important because the biggest constraints on spacecraft processing are: power budget, radiation hardiness, and thermal.

I was able to find an image of the actual satellite in assembly. From this we can guess that there is probably not more than a square meter of solar on-board, so we can give it a round 1300W of power. I couldn’t find any orbital parameters(If Gunter doesn’t have it, who does?), but given it’s main task is as an imager, we can assume LEO, and so this 1300W isn’t going to be constant since the spacecraft will most likely be eclipsed part of the time.

Generous 1000W average solar flux, generous 25% panel efficiency, 250W/h.

So lets look at rad hard processors. They have to be either shielded or run multiple and do voting, though even that isn’t fully acceptable as some SEU (single event upset) can cause permanent damage and leave you down a voting member. The latest and greatest RAD5545 advertises 5.6 giga-operations per second (GOPS) at 20 watts, so if we assume (artlessly, and likely incorrectly) a linear power usage, the 80 TOPS of the WJ-1A should need some 280kW. So we know they aren’t using a typical rad-hard CPU topology for their AI models. I see that Corel/Google advertise 2 TOPS per watt on their edge TPUs (Tensor Processing Unit).

So assume a large ASIC (application specific integrated circuit) at the same efficiency of 2TOPS/W, with 4x multiples for voting and we get a far more reasonable 160W. Still a LOT of power on orbit for such a small spacecraft, but actually possible.

So for thermal limits, do they run the TPU only on the dark side in place of their on-board heater? The have some white panels that might be radiators, but it’s hard to say.

Hard to say from these fluff articles. I really want to hear:

• What’s the efficiency on the TPU?
• How did they make it rad-hard, and how long do they expect it to last?
• What models do they run on the edge?
• What is their downlink budget? Can they pull full imagery if they want it or are they limited to ML analysis only?

I expect to see more ML in space, but to be honest I did not expect it to be in such a small form factor.