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Kepler-Patryk59 karma

We control the thermal optical properties of the spacecraft by matching our known orbit to the material properties of the satellite coating.

Internally we use thermal materials to transfer heat between the satellite mass and the electronic components. All of this data is entered into a giant thermal model that lets us predict the temperature range we will experience. Our goal is to keep temps between 0-80C-ish.

We stay away from electrolytic caps, any liquid are banned, and use lithium ion batteries, like a phone has. Fun fact, the batteries need their own heater to keep them in their specific temperature range.

Kepler-Patryk54 karma

Great question. One of the big benefits of operating in LEO orbits is a substantially lower radiation level than GEO orbit. Also, LEO sats are significantly less expensive and operate in a different risk tolerance. Therefore we're able to use new technologies that have lower radiation tolerance and utilize redundancy methodologies to reduce the risk further. I can't specify the exact parts that we use but we're using processors, FPGAs, and SOCs that have been released in the last 5 years.

Kepler-Patryk39 karma

I think there was a company that just announced it a day or two ago. It's def a big topic in the space industry. If I can find the post I'll add it. It's an important topic, not just because of satellite avoidance but we need to play nice with astronomers that monitor our skies. We need to make sure we don't create reflective garbage for them.

Kepler-Patryk37 karma

It's funny, there are huge parallels. The payload of the satellite is usually 80-90% identical in function and sometimes hardware to a ground station. It's a huge processing hub with a ton of filtering, modulation, etc + antennas.

The main difference comes into play on the bus side of the satellite which includes the solar panels, batteries, power and battery management system, a half dozen sensors to know where the sat is and what orientation it has.

This might sounds lame, but if I had a time bubble, I'd actually be doing what we're currently working on. It's a very exciting project to add connectivity in space. With a non unlimited budget and timeline, it just means that we have to maneuver our development in a way that allows us to hit targets and make continuous improvements.

Kepler-Patryk27 karma

ents can cause erroneous signals to be output by the circuit, resulting in data loss/corruption in the case of digital/analog/mixed signal circuits or supply voltage fluctuations in the case of power circuits. In some cases, especially in power circuits, the SET can cause catastrophic failure of the device resulting in its destruction. Modern digital processes are usually fairly resilient against TID effects due to the transistors having very thin gate dielectrics (which don’t trap much accumulated charge over time) and heavily doped channels which better resist inversion. This is why you might see more modern processors being used in spacecraft. Where you might get in trouble are the Single Event Effects, if the system doesn’t have robust error control, but that can be addressed through proper system design. Where you typically might want to avoid off-the-shelf products are the power systems, because power transistors are extremely vulnerable to destructive Single Event Effects. I

Great writeup! When designing for LEO, proper system design is key to reducing risk while keeping costs down. The power system / EPS needs more care as you've stated. Cheers!