Black coatings are important for space systems to ensure the elimination of unwanted electromagnetic radiation and optimize the functioning as well as the output of the system.
This article discusses how space mission costs can be optimized using black coatings. It also provides an extended outlook on Acktar‘s light absorbing coatings, their applications in space missions, and how the company’s black coatings have played key roles in recent missions.
The article was developed in collaboration with ACM Coatings GmbH (subsidiary of Acktar Ltd.), a paying participant in the satsearch membership program.
Introduction to black coatings in space
Space is a highly radiation-driven ecosystem where the systems and instruments can be disrupted due to unwanted electromagnetic radiation, further leading to the malfunction of the instrument and its overall final output. This is primarily important for scientific space missions consisting of a series of optical instruments or payloads.
In every optical instrument, there is some stray light, which is unwanted electromagnetic radiation that reaches the sensor and decreases the signal-to-noise ratio. This “noise” causes distortions in the optical image or photometric errors. An example of this noise can be found in the following image, where the flare and the rays withhold the landscape.
A prominent solution for stray light is a black coating. These coatings absorb the stray light and prevent it from reaching the lens. While many solutions can appear “black” on the visible spectrum, they can underperform when it comes to the Extreme Ultraviolet (EUV) or Infrared (IR) spectrum. Acktar’s black coating exhibit low reflectance from EUV to Far Infrared (FIR).
Acktar’s deep black coatings and coated films are widely used in optics and photonics applications. It not only helps them to suppress and absorb scattered light but also to absorb laser power. In addition, 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. The ability to absorb laser power, especially referring to a high laser-induced damage threshold of the coating can be relevant for free space, and laser communication in complex systems, which may also need stray light suppression
The generation of high emissivity of surfaces can be used very well with passive thermal management, but also for infrared calibration targets. This is also proven by numerous of Acktar´s work on global space missions.
Applications in space missions
The NewSpace companies operate with a prime focus on low-cost and high-quality products/services. Therefore, NewSpace projects require cost optimization, which according to Acktar, can be realized mainly through higher volumes of the components.
Considering the increasing demand for components and mass production facilities, the coating services also need to meet this higher volume of demands. Acktar’s self-developed proprietary coating technologies are so variable and flexible that is possible to coat even larger quantities of components. And as the quantity is increased, the cost for the coating decreases.
The next aspect is the component size. The size of the components to be coated is usually much smaller for a NewSpace project than for components used in large space missions such as cameras and the component size also has a significant impact on the construction. While we all sometimes experience stray light distortions in our cameras, stray light suppression becomes critical in sensitive optical systems, such as star trackers, telescopes, EO cameras of satellites, or lasers.
In space observatories that look for distant and faint objects in space, or the Earth Observation (EO) cameras of satellites that aim to create a 3 to 5 m imagery, in this, the resolution is the key element for the final output. Straylight in these optical systems degrades resolution, as reported in the Gaia telescope in 2013. Therefore, black coatings, by reducing the stray light, increase the performance as well as enhance the final output from the system.
In some components, the use of black coatings and other stray light suppression methods is crucial not only for the performance but for the actual functionality of the components. Star trackers, for instance, are optical devices that measure the positions of stars by photosensors or cameras in order to determine the satellite/spacecraft’s orientation. Straylight in star trackers can cause wrong orientation detection and therefore result in wrong navigation of the spacecraft, as happened in the Beresheet Lunar Lander project in 2019.
Acktar’s broad focus in the space market
Acktar has been a part of several prestigious space missions, proving that the global space entities have not only realized the importance of its product/services but also showcased that the company’s solutions are competitive in the global market.
Acktar delivers space-qualified coating solutions for stray light suppression, passive thermal management, and ATOX protection. With more than 50 space projects and 30,000 coated parts already in space, Acktar’s space heritage reaches almost anywhere in the Solar System. Whether it is LEO, GEO, Moon, Mars or L2 Acktar coatings are THERE.
Acktar coatings are primarily preferred by the global space market as they exhibit:
- Low outgassing (CVCM 0.001%, RML 0.2%)
- No contamination
- Thermal stability (4K-723 K)
- Vibration stability
- Atomic oxygen resistant
- Radiation resistance – measured up to 200 mrad
Acktar’s coatings also show negligible degradation over time. For example, the JWST parts have been coated in 2007 and due to repeated mission delays, it was launched at the end of 2021. Before the launch, Acktar tested the coated samples to ensure the performance after 14 years of storage and recorded no degradation. This also proves in the process that Acktar’s coating solutions have a long shelf life.
As the NewSpace market continues to expand, Acktar’s coatings will be crucial to ensure the smooth functioning of the components, systems, or instruments in space missions.
Cost optimization for customers through black coatings
One of the key aspects that remains essential for modern space systems is the cost optimization of customized products or systems. This also depends on the customers, as their space systems may vary as per the mission requirements. In the customization segment, whether we are talking about the NewSpace or traditional space projects, the best performance with the lightest and most compact system is possible by utilizing black coatings. The Black coatings enhance performance without changing the mechanical design and maintaining the weight of the system.
The black coating services may also vary depending on the customization aspect. For example, sometimes foil or rolls can be used in place of just coatings. Acktar particularly offers foils and rolls of coatings as off-the-shelf products, offering the “traditional space” quality coatings at NewSpace prices and short timescales.
This further helps the customer optimize the mission cost with the quality of product/service utilized for “traditional space.”
Future outlook on serving the global market
Space systems have evolved over the years and the NewSpace era has pushed the companies to develop innovative solutions, with quality same as “traditional space”, but at a much more affordable price. This has also paved the way for more opportunities and the custom design of space missions. Acktar’s product lines and services have a proven capability to meet the increasing demand of the global space market.
To find out more about Acktar and for more information on its product and services portfolio, please view the company’s supplier hub on satsearch.