Improving optical performance in NewSpace missions using black coatings – with ACM Coatings of Acktar

Podcast

Episode 32 of the Space Industry podcast is a discussion with Alexander Telle, CEO of satsearch member ACM Coatings GmbH of Acktar Ltd. on the uses of optical coatings and foils for space hardware.

Contents


Episode show notes

ACM Coatings specializes in ultra-black coatings and foils that improve the efficiency and performance of optical equipment.

In this episode we discuss how coatings can be used to suppress stray light, and reduce noise and reflections, as well as how to integrate them into space equipment for missions. We cover:

  • How black coatings are leveraged in space missions
  • Qualification and testing requirements for NewSpace missions
  • What satellite camera manufacturers need to consider in order to enhance optical performance
  • Recommendations for designers of star trackers and other optical sensors for satellites

Acktar’s satsearch portfolio

The Acktar Blackened Precision Air Slit is a space-qualified, high-precision air slit with both sides coated in Acktar's Vacuum Black. It also has coating for the internal aperture edge. The product is available wide range of sizes. It has a thickness of 0.0007 inch (17µm) and has variety of slit sizes ranging between 25µm to 1000µm.

The Acktar Blackened Precision Pinhole is a space-qualified product. It has a high precision pinhole with two sides coated by Acktar's Vacuum Black. It also has coating for the internal aperture edge. The product is available in a wide range of sizes. It has a thickness of 0.0007 inch (17µm) and has variety of pinhole sizes ranging between 20µm to 1000µm.

Acktar's Black-coated Foils and Films provide large-area optical enhancement for a variety of applications. The coverings can be used when a large surface area requires protection, high volume hardware is in use, and/or the surfaces operate in harsh environments that degrade their light-absorbing performance, requiring regular renewal. Black foil coatings are available as sheets, die-cuts or rolls, either with or without an adhesive backing.

Acktar Hexa Black Light Trap Sheets are space-qualified, light-absorbing sheets designed for space applications. It is used to eliminate stray light reflectance in applications where grazing angles are an issue. It's unique structure and coating of hexa black allows extremely low reflection from 40° to 88° angle of incidence (AOI). The product is available in a wide range of standard sizes along with customizing options.

The Acktar Hexa Black Noise Reduction Extension Tubes are space-qualified tubes primarily used as spacers to increase the image distance when using SM1-Mount, C-Mount, and CS-Mount instruments for cameras and camera lenses. It has a wavelength range between 200nm – 5µm and can be used in between lens and a camera to extend the focal length and increase the effective aperture of the lens.

The Acktar Laser Beam Dump - 30mm is a tube laser beam dump designed to use in laboratory and optical systems. It has a vacuum black and metal velvet foil coating. With 1.1 inches (approximately 30mm) maximum beam diameter, it operates in the wavelength ranging between 100nm - 10µm. It is suitable for CW laser up to 10W/cm2. It has an optional C-Mount, an additional replacement ring with maximum beam diameter of 0.97 inch (approximately 24.7mm).

The Acktar Laser Beam Dump - 51mm is a tube laser beam dump designed to use in laboratory and optical systems. It has a vacuum black and metal velvet foil coating. With 2 inches (approximately 51mm) maximum beam diameter, it operates in the wavelength ranging between 100nm - 10µm. It is suitable for CW laser up to 10W/cm2.

The Acktar Laser Beam Dump - 81mm is a flat laser beam dump designed to use in laboratory and optical systems. It has a vacuum black coating. With 3.2 inches (approximately 80mm) maximum beam diameter, it operates in the wavelength ranging between 100nm - 10µm. It is suitable for CW laser up to 10W/cm2.

The Acktar Hexa Black™ is a space-qualified light-absorbing panel designed for use in optical space systems. It is used to eliminate stray light reflectance in applications where grazing angles are an issue. The unique structure and coating of hexa black allows extremely low reflection from 0° to 88° angle of incidence (AOI). The product is available in wide range of standard sizes along with custom options to suit the needs of the customers.

The Acktar Metal Velvet™ is a space-qualified light-absorbing panel designed for use in optical space systems. It is used to eliminate stray light reflectance in optical applications. Some of its key features include extremely low hemispherical reflectance and high emissivity with low reflectance and low outgassing. The product is available in wide range of standard sizes along with customizing options to suit the needs of the customers.

The Acktar Spectral Black™ is a space-qualified light-absorbing panel designed for use in optical space systems. It is used to eliminate stray light reflectance in optical applications. Some of its key features include moderate abrasion resistance and high emissivity with low reflectance and low outgassing. The product is available in wide range of standard sizes along with customizing options to suit the needs of the customers.

An ultra-diffusive, wideband (EUV-FIR), absorbing aluminium foil with 99.9% specular absorptance. The high adhesion, space-qualified material has a long-term operational temperature range of -250°C to +350°C and features low outgassing, with a CVCM < 0.001.

A semi-specular, wideband, absorbing aluminium foil for contaminated environments where the surface needs to be periodically renewed. Spectral Black delivers wideband, low reflectance for FUV, UV, VIS, SWIR, MWIR and LWIR.

A polyimide film designed to deliver low reflectance and high emissivity across the spectrum from UV thru VIS to SWIR, for straylight suppression. The film is a few microns thick, with no particulation, and is vacuum and thermal—vacuum cycling qualified.

Acktar™️ produces black-coated optomechanical components and mounts for optical applications that are suitable for reducing noise, unwanted reflections, and increasing the efficiency of the optical system.

Custom black coating service

The company also provides bespoke coating for a wide variety of opto-mechanical parts, as well as undertaking build-to-print manufacturing of the parts and assembly after coating.

The black coatings are designed to provide low reflectance, high thermal stability, high absorptance, high emissivity, excellent adhesion to essentially all materials, and low outgassing in a few microns of a coating.


Episode transcript

Please note that while we have endeavored to produce a transcript that matches the audio as closely as possible, there may be slight differences in the text below. If you would like anything in this transcript clarified, or have any other questions or comments, please contact us today.


Hywel: Hello everybody. I’m your host Hywel Curtis. And I’d like to welcome you to the space industry by satsearch, where we share stories about the companies taking us into orbit. In this podcast, we delve into the opinions and expertise of the people behind the commercial space organizations of today who could become the household names of tomorrow.

Before we get started with the episode. Remember, you can find out more information about the suppliers, products, and innovations that are mentioned in this discussion on the global marketplace for space at satsearch.com.

Hello everybody. And welcome to the episode I’m joined today by Alexander Telle, CEO of satsearch member ACM coatings, which is a company based in Germany.

ACM coatings is a subsidiary of Acktar, a company based in Israel and specializes in ultra black coatings and foils that improve the efficiency and performance of optical equipment. In this episode, we’re going to be discussing how black coatings can be used to suppress stray light, reduce noise, and reduce reflections in space, particularly in NewSpace applications.

So firstly Alexander, I’d like to welcome you to the space industry podcast and yeah. So see if there’s anything you’d like to add to that introduction.


Alexander: Thank you very much for the introduction. It’s perfect, and we are really glad to have the ability to speak with you today.


Hywel: Okay, fantastic. So let’s get into this, this is quite an interesting topic. We constantly deal with the software and the hardware, in particular of space companies that the individual sub-systems and components. Whereas what ACM coatings does is to improve the performance of those components.

So I wondered if you could provide a quick overview of how black coatings are leveraged in space missions and the sort of components on which they are used and how they can influence that performance from the missions perspective?


Alexander: Acktar’s deep black coatings and coated films are widely used in optics and photonics applications. And you can perfectly use them to suppress and absorb scattered light, but also to absorb laser power. And in addition to make surfaces with a high emissivity. And these properties have a high potential for space missions.

Stray light suppression plays a major role in optical and photonic payloads like cameras, spectrum meters, or telescopes, but also in solar sensors or star trackers. This is a considerable issue. The ability to absorb laser power, especially referring to a high laser induced damage threshold of the coating can be relevant for free space, laser communication in complex systems, which may also need stray light suppression in addition.

The generation of high emissivity of surfaces can be used very well with passive thermal management, but also for infrared calibration targets. This is already proven by a numerous space missions, to which we can return later.


Hywel: Okay. Interesting. So yes, quite a wide range there. And as you say, multiple uses in a singular application, both the improvement of the performance and the suppression of the stray light.

So we’re very interested traditionally in optimizing stray light, carefully to, with great precision has been very important for missions by the space agencies and larger manufacturers.

Do you find that NewSpace companies have requirements that are different from these, from the agencies and the large OEMs for that legacy missions have typically needed, or the requirements along the same lines – is the need the same?


Alexander: Yes and no, the general goal of all large mission projects as well as NewSpace projects is the optimal optical performance under space conditions. It is well known that the environmental conditions are different depending on the requirements in NewSpace or earth observation or a deep space project

Our coating technology performs in both worlds, in big space, like space agencies, instrument projects, with the same two words, as in NewSpace projects with maybe a high-volume industrialization comes into play. This is because. It is here where we can perfectly combine our expertise from 25 years of space heritage, and the experience from industrial serious production.

This is the key difference to our competitors in the market for space-qualified coatings. Space is only one part of our company DNA cause our coatings and firms have always achieved. Our production records in industrial photonic application. And serious productions such as sensors, medical technology, new analytics, laser applications, or even in the automotive industry.

And maybe our difference is that NewSpace projects also require cost optimization, which in our case can be realized mainly through higher volumes of the components. Our self-developed proprietary coating machines are so variable and flexible that is possibly to coat even larger quantities of components. And as the quantity is increased, the cost for the coating decreases.

The second related aspect is that the component size. The size of the components to be coated are usually much smaller of a NewSpace project then for components such as cameras or telescopes for large missions and the component size also has a significant impact on the construction.


Hywel: Yeah. Yeah. I imagine it would be really interesting. If the work that you’ve done in other industries, particularly, like you mentioned medical industries, there, there are quite stringent qualification requirements.

So, bringing that experience of going through those compliance procedures outside of space, into space as well, must be interesting to know their qualification requirements for Commercial-Off-the-Shelf (COTS) NewSpace components, for outgassing, thermal stability, radiation, and so on.

These are often different from the ECSS-driven space agency mission requirements for deep space exploration, travel to other planets. Are there any specific qualification requirements that you’ve had to change or adapt in your solutions in order to tailor to the NewSpace market?


Alexander: On the one hand, it’s true that deep space missions or missions to other planets have different requirements, perhaps more demanding requirements in missions, in low earth orbit for NewSpace applications.

On the other hand, we have always large missions, like the panic was for better satellites, which were in Low Earth Orbit (LEO) with relatively the same requirements, especially focus now with NewSpace components is of course always the resistance to atomic oxygen. In recent months, we have carried out various additional qualification tests in collaboration with our customers, and we’re able to show that all our coatings, but also our coated films are perfectly resistant against atomic oxygen.

In addition, we can say. That we have coatings that have been qualified for large missions and extreme temperature ranges. For example, coating qualified for use at cryogenic temperatures like for the famous James Webb space telescope, or a coating qualified for very high temperatures on the other end up to plus 550 degrees Celsius, like for the mission to Mercury.

If as you have coatings that are qualified in this broad spectrum. It’s much easier to respond to the requirements for NewSpace than the other way around.

What is playing an increasingly important role is the topic of as a form of management for entire satellites, but also for sub-areas instruments. And for this purpose, we have developed new materials based on our roller coating technology.

We can coat a thin film substrate, typically polyimide-like with either deep black coatings, which has high emissivity and high solar absorption or with a white coating option, which has relatively high emissivity at a relatively low solar absorption to improve the passive temperature management of small satellites.


Hywel: It’s very much about the performance requirements of the individual components and subsystems rather than what the mission overall is trying to achieve. Because as you’re saying, if the coatings in the films are qualified for large temperature ranges and stringent requirements, you’re able to adapt them to meet different aspects without too much change.

Let’s say one area. So let’s take cameras. As an example , obviously, you’d imagine the optical requirements in cameras would demand lots of use of minimizing street lights and optimizing optical performance. There are several COTS camera manufacturers emerging that are targeted in the NewSpace market in visible, near infrared shortwave infrared bands and across different spatial resolutions as well.

And we talk a lot about these sort of applications. We hear a lot about them and in the industry and the end users are growing as well, but of course, everything in space comes with trade-offs. So what are the kinds of trade-offs that such camera manufacturers or the users of them would need to consider when selecting the right sorts of coatings and substrates to increase the overall performance.


Alexander: The first thing to not is that stray light and optical performance, of course, dependent on the wavelength range of the application. Stray light problems often arise when you take an existing system design that comes from the visible wavelength range and change the wavelength range to near or shortwave infrared.

They’re at your offices stray light effects that will not see in the visible range. So what is the reason for this? The reason is that the absorption of light in surfaces in our case in black surfaces is wavelength dependent and surfaces frequently use in technology such as anodizing actually only absorb light in the visible range and become transparent or even reflective in the infrared or even already the near infrared starting at 650 nanometers.

This means that the opto-mechanical components, if used for my lens, that perfectly worked in the visible range. Already act like reflectors in the near infrared and can massively deteriorate performance. In contrast, we can claim without deep black coatings that they absorb in an extremely wide range from UV over the visible, into far into infrared.

We cover everything up to a max wavelength of 15 micrometres and this also covers all photonic applications that we see today for the NewSpace market. Long story short, the wavelength range plays a major role in the consideration of this topic. As soon as you get into the infrared range, stray light issues are much more critical and cannot be tackled with conventional surfaces.

This also means that you cannot avoid creating a new stray light design for your specific product line and answering the questions about optical performance in stray light suppression with this design. The advantage is that already on the hardware side, you have the possibility to exert a great influence on the performance of the optical system and both all on the contrast and the image quality.

And not only later in the image processing in the software, which has to eliminate these effects. The goal should be always to realize an image that it is good. It’s necessary for the application on the one hand and on the other hand, you would like to match as many customer requirements and applications as possible with such optical system for the NewSpace.


Hywel: Brilliant. So as good as onboard data processing and image post-processing are becoming. If you could improve the quality of the pictures coming into the system in the first place, then you’re obviously going to get a better result. I’m very interested in that you say cameras, as an example, can be adapted from different wavelengths, but not without some optimization calibration work, which as you’ve said to sounds just vital.

Yeah, that’s great. Thank you. And that’s on the payload side, obviously. I wondered if you also had any recommendations for teams that are using or designing for yeah, from the supplier side staff design star trackers or some sensors, these navigational components that have the can be effected by stray lights and reflection.


Alexander: I can say that the topic of reflection suppression should be considered as, in the development, this can also lead to the advantage of lowering the degree of complexity. If you use suitable absorption layer for stray light baffles also, solar baffles and entrance baffles. For example, if you use a powerful surface treatment, one could make the component smaller or shorter.

This means that you can reassign a certain number of wanes or apertures. So the complexity is reduced. The number of components is reduced. And with that, the cost of such a system is reduced. It is a good solution working reliably for a long time without showing any degradation effects. By the way, we have available a full database of stray light and reflection measurements for all our coatings.

This data is called ERDF, which is E directional reflectance distribution function and the is used and stray light design analysis software. Using this data enable you to see the effect of our coatings very early in the development process. Just reach out to us and we’ll make it a available for you.


Hywel: We can link to that. Definitely in the show notes of the episode. You can’t overemphasize. I think the benefits that simplicity could bring in the space in any space hardware, reducing everything that you require in that process and time, power requirements, everything. So that’s a really good point there.

So thank you. I think just to finalize here, there’s an array of a different component manufacturers focused on sun sensors, star trackers, cameras as we’ve mentioned and various other kinds of optical technology, some you mentioned earlier in satellite links with optical communications, lots of these are emerging for NewSpace, for the NewSpace market at the moment. How do you see the market for you as a coatings provider evolving in the next, say five to seven years, not withstanding pandemics and global invasions.


Alexander: Yeah in general, for photonics, not only for space has always been a growth market. We see with the NewSpace movement is strong demand, strong growing demand for surface solutions, a solution for absorbing surfaces, in our case, especially this fast growing market with new companies, new players coming in can become more confusing therefore communication platforms and supplier platforms like satsearch play a big and important role in our daily work. On the one hand it to be visible to the industry, but also to give us a better understanding of the new players and their requirements. It’s fair to say that we have very positive view of the market.

And of course we want to grow with it. We are permanently looking for new fields of application for surfaces, besides the classic stray lights suppression for cameras, telescopes, or spectrometers, star trackers, and solar sensors. Of course, we do see all the big potential for laser absorption. Especially big potential for laser or satellite communication and free space communication but also for passive thermal management for instruments and satellites.


Hywel: Fantastic. Thank you. That’s a very wide range of areas. Very exciting outlook for you guys there. That’s that’s everything I wanted to cover. I really appreciate you being able to spend the time with us today. And I think the listener base will have learned a lot about the importance of coatings, the applications of coatings and files in different situations and how to manage the trade-offs and the considerations from both let’s users, potentially a supplier’s point of view. So to thank you very much for your time and attention today, Alex.


Alexander: Thank you. It was a big pleasure to speak with you today.


Hywel: Thank you. And to all our listeners out there, you can find out more about Acktar and ACM coatings on the satsearch platform. We’ll then provide you some links in the show notes to this show and you can reach out to Alex and the company and the team there with any of your questions about the material that we’ve covered today. There’s also information about lead times, data sheets and all sorts that we can help you access, and we will be happy to help you then with anything you need your procurement or trade study. Thank you very much.

Thank you for listening to this episode of the Space industry by satsearch. I hope you enjoy today’s story about one of the companies taking us into orbit. We’ll be back soon with more in-depth behind the scenes insights from private space businesses.

In the meantime, you can go to satsearch.com for more information on the space industry today, or find us on social media, if you have any questions or comments. Stay up to date, please subscribe to our weekly newsletter and you can also get each podcast on demand on iTunes, Spotify, the Google play store, or whichever podcast service you typically use.

engineering
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