I'm Patryk Laskowski, Hardware Design Manager for Kepler Communications. I work in the space industry and design and build satellites and am bringing the internet to space. AMA

What's the semiconductor technology you guys use for satellites? I believe I read that NASA uses old chips from Intel because the old process node (maybe like 140nm? I think ita from the early 2000s) is highly resistant to high energy particles.

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.

There are two basic types of radiation concerns for semiconductor devices and ICs. One is the long-term Total Ionizing Dose (TID) absorbed throughout the life of the product, typically measured in kilorads. The other is Single Event Effects (SEE) resulting from individual high energy particles like protons and galactic cosmic rays (heavy ions). TID will induce parametric shifts in transistors and circuits, such as shifts in leakage current and transistor gate turn-on voltage. Basically everything starts to drift out of spec. In extreme cases this can result in eventual loss of control over individual transistors, which renders the circuit non- functional. SEE are different in that they are extremely short-duration events which generate a transient current pulse in the affected device. The pulse is known as a Single Event Transient (SET). These transients 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. In those and other high voltage systems you’ll want to use radiation-hardened components.

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!

Thanks! I appreciate the rare opportunity to talk about this stuff. Good luck with the constellation!

Thank you and anytime!

Not old chips. Robust reliable chip designs that can withstand harsh conditions. Turns out that the Validation process is very difficult and old chips have been tested and prooven.

It’s true that older transistors with larger feature sizes are less sensitive to some Single Event Effects. Aside from that, spacecraft manufacturers are generally very risk averse and hesitant to take a chance on new semiconductor technology. They would prefer to use components with proven flight history whenever possible, because there’s only so much we can predict here on Earth about reliability in space. So yeah, you’ll see very old semiconductor technology in some brand new satellites. If it ain’t broke, don’t fix it! And yes, the process of engineering and testing electronics for space environments is expensive, time consuming, and technically challenging. For all these reasons, advancement in space-grade technology tends to be relatively slow compared to other electronics.

There's a new trend with IC manufacturers to support LEO space. GEO requires a very high rad tolerance that requires special mfg processes and a very high level of testing. LEO doesn't need these levels and vendors have been manufacturing parts that have a 5-10k rad hardening which is accomplished via a different package on a standard part. It's an easy and significantly cheaper way to add radiation protection to a design in areas of need.

How do you maintain the temperature for the electronics in a satellite? I mean, how do you ensure that it won't radiate too much heat and cool down too much, but also that the satellite won't absorb too much heat from the Sun?

What do you do about components containing liquids like electrolytic capacitors and batteries, can they be used at all in vacuum and low temperatures?

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.

When designing and building a platform for space, what would you say are the biggest parallels from ground based applications that you can apply to space based applicstions? What are the biggest differences?

Also, if you were told your team suddenly had an unlimited budget and could work in a time dilation bubble to address one challenge with your microsatellites, what challenge would that be?

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.

how long until the time bubble is launched?

Hahaha you'll have to wait and see

Hello,

There is a lot of space debris up there in orbit. How close are we to get a " space garbage truck" up in orbit to clean all that junk?

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.

Software tools in multiple fields have bloomed with open platform design, what kind of resources in the realm of aerospace hardware could you see drawing benefit from being iterated on in an open development process? Are there tool kits that you'd like to have better access to?

This is a great question but a difficult one to answer. Hardware designed for space is heavily protected by regulations such as CGP and ITAR which makes it very difficult to design in an open crowd sourced fashion. You'd be able to put together a team and get clearance within your government body but it would be limited to a specific country.

It's' def a interesting idea and I would love to see what kind of design we'd get to. One way to get involved currently is via University cubeSat clubs and this is one of the best examples that I know of when it comes to a limited crowd sourced project.

With wi-fi mesh networks, there's actually a feature that allows you to pinpoint the location of devices depending on their signal strength relative to different nodes. Could Kepler's network be used as a secondary tracking system for space assets, reducing the margin of error when paired with traditional TERs?

It's a fantastic idea. We'd have to chat with our network architecture team to see how this would pan out.

Hey there! I was wondering what happens to your satellites after they're done. Do you have a program for recollection or anything? Thank you

Great question! We have a de-orbit strategy for anything that we put up in orbit. We work with regulatory bodies to not only make sure we abide by their rules and best practices but also push for improvements into future orbit sustainability.

What's the hardest thing about designing satellites?

Surprisingly it's not too different from designing commercial hardware. Because we design LEO which has a 3-5 year life, we're able to use automotive grade components. Radiation levels are also significantly lower in our orbit. We have to pay special attention to microprocessors and memory which is always more sensitive to radiation. Lastly, all of our assembly must be leaded vs ROHS as tin whiskers are significantly more likely in space.

Some additional fun facts about designing for space. We get to have a thermal vacuum chamber in our lab to test how our satellites will behave and function in space. Vibration testing is heavily modelled on the transportation of the sat from our office to orbit and not actually on it's functional environment. And lastly, you can't put a fan on it for thermals as there's nothing to blow lol

Haha, yeah, no fan makes sense. How do you cool it then?

We utilize the satellite mass to spread the heat out and radiate into space

Hi. What is the latest technology that yet has to be implemented into your work that you're exited to use?

Good question, I'm super stoked to be working with Optical and propulsion which are on our research list for out upcoming new gen of sats.

Like ion propulsion?

We're looking at a number of options at the moment, a bit early to tell

What are you thoughts about astronomer and sky gazers concerns that satellites will pollute the night sky?

It's a big concern and has been an active topic for a couple of years. It's important to find ways to minimize impact. Big part of it is reducing the reflective surface of a sat.

Congratulations on the deal with MDA! Could you talk about how Kepler will be assisting with the moon rovers? For example, is there a specific set of instruments that Kepler will be designing?

Thank you! We're super excited for this opportunity of having our hardware go to the moon. Our main concentration is on communication from the rover to the lander and earth + solar panels. Fun fact, one of the biggest challenges on this project will be surviving a lunar night which dips down to -240C with no heaters! Fingers crossed :)

Guessing you'll need something more than thermal straps :). What factors are you looking at for rover solar panels compared to the ones on Keplers GEN1/2 satellites?

It's still a big unknown for us and will be a learning experience to understand the lunar environment. We'll be working closely with MDA and CSA to understand these new challenges. We'll need articulation to move solar panels. We'll need to understand how to protect them from dust that gets energized by our landing. We'll need to pay very close attention to PCB copper balancing in order to prevent / minimize board warpage during extreme temperature changes.

Can you use generative breaking to generate heat? Like rover doing a break dance!

Love it! Unfortunately that won't help us too much. The cold temp problem happens at Lunar nights when the rovers are scheduled to be fully shut down because our battery will not be big enough to keep us powered for the 14 day "lunar night"

Hi. I keep reading all of these end of the world novels and it begs the question: how long would satellites be operable without humans?

Hahaha nice! LEO is usually less than 5 years. GEO is usually less than 30 years. But that is based on us keeping the sats away crashing into each other and other objects.

What is the advice would you give to junior hardware engineers trying to work in the space industry and become technically strong as well?

Great question! There's a lot of great ways to build hardware skills. Two things that I look at when reviewing resumes is personal projects and uni clubs. These are great ways to break into the industry. You don't need to specifically have space design experience when applying to a position as 90%+ of hardware design knowledge is transferable. There's also some great satellite systems books that can familiarize you with the satellite architecture. And lastly (shameful plug) keep an eye on our career page as we're constantly looking for new talent!

Does grounding help negate radiation in space? … and how do you ground circuits in space anyway?

Unfortunately no. The main way to negate radiation is shielding (the thicker the better) or using technology that's naturally immune eg. using FRAM memory vs SRAM.

From concept to deployed payload, what are steps that Kepler goes through when developing a new system? How do all of the different teams stay coordinated as designs change over a project's life cycle?

Great question. It's takes many levels of coordination and planning. We use a IPT (integrated product teams) system. The satellite is divided into major functional subsystems. Each of these subsystem has it's own IPT that is responsible for it's delivery and alignment to the full satellite system. Projects start in a pathfinding stage which is used to de-risk new technology or new ideas. This is done whole all the requirements are finalized. From the pathfinding stage you transition into revisions that converge more closely to the final requirements. There's a great article from NASA that goes through a lot of these details: https://www.nasa.gov/seh/3-project-life-cycle

Are there any challenges we don’t hear about as much, such as political concerns over satellite spying, etc.? Or use for defense reasons?

Political spying hasn't been something we've encountered as of yet. One of the biggest challenges for the market and for getting into the "space" is frequency regulation. The process to get permission to use different frequency bands can be a long and complicated process.

Can I come for a tour? Your guys aren't that far.

Due to covid we've put open house nights on hold. But we hope to return to these when it's safe to do so. We can't wait to open up to the community again!

Do you think Space needs the Internet?

Definitely! How else can we facetime aliens?

Do they call you "The Big Laskowski"?

Because you seem like "the dude" of space tech electrical stuff.

So if they don't, dammit, they should.

Oh no! They didn't but they will now.

What impact do you think fpgas will have in your industry?

FPGAs are huge in LEO. They're already heavily used :)

Do you believe in aliens?

Personally yes. I think it's a cool prospect that there's a planet out there similar to ours and they're trying to bring internet to space as well.

Fun thought. If we ever do find this planet, can you imagine the work of trying to sync our tech together? Here on earth we can't agree on a universal power outlet, this would be next level.

I'm so sorry, I missed your AMA but I did have one question!

I've heard the possibility of satellite internet being faster than fiber on-ground latency-wise because light can travel faster through the vacuum of space - how true is that and as a gamer, how excited should I be for this?

The answer to this isn't an easy one to answer. We're able to use a variety of technology to transmit data eg. Optical (lasers) running at 10Gbs or use ultra high frequency bands such as KA or V which are 30-75 GHz. But the technology to send and receive gets significantly more complicated and expensive. Space to earth is difficult wrt latency because it requires satellites to be in constant view of your receiver and this requires 10s of thousands satellites. The industry as a whole is moving towards solutions that will reduce the number of sats needed while increasing speeds and performance. But this will take some time. But yes we should be able to achieve something faster than fiber.

What's being done about the accumulated space debris in LEO?

There's some fantastic work being done to reduce space debris and many space companies are working to improve their de-orbit plans. It's a very big topic right now.

Hi there, I know this is a bit late but I just saw this and is really close to where I am trying to aim my career.

Do you need a PhD to work on the stuff you are working on? How far does a Bachelor, Masters, PhD get you in terms of design of satellites and space tech (like you mentioned space stations, telescopes, etc.) I never had the chance to really ask anyone this.

I really am interested in being a part of contributing to future inventions and technology that gives us the realistic possibility of survivability on Mars and beyond! Kind of like adhoc for Elon Musks goal.

No hurry for a response, but would be great to hear from you as I am Polish too (seeing your last name)!

We hire at all levels. Most people at Kepler are a mix of Bachelors or Masters. We've had interns that design hardware for space. It's all about passion, knowledge, and dedication. We outsource the rocket science :P

How's the signal out there?

Amazing!

We’re 10 years in the future. What’s it looking like?

The industry trends are showing that we're going to have big growth in space tech and exploration. I think we're going to see things that our minds can't even fathom today. Maybe a mini colony, that would be pretty fun.

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Is this Mark Michael? lol

How's your documentation? Need an additional tech writer?

Documentation is super important. If you're interested, check out our careers page.

Hi Patryk! Your work is fascinating, but more importantly we have the same last name! I was a bit startled when I saw it! On average, how many times a week does somebody butcher the pronunciation?

Hahaha I've given up on counting

Does Kepler's IOT service utilize technology like LoRaWAN standard for the ground based portion of the communication?

It's a constantly changing scene. Our first devkits were LoRa based. Future developments are looking at a number of new and upcoming options.