Steel in Space: Material Innovations For Satellite Manufacturing

“Space” materials are usually associated with titanium alloys and composites. Meanwhile, steel is associated with earthly bridges and workshops. However, in reality, it remains an important link in the satellite industry. It is found in everything from bearings and precision fasteners inside spacecraft to the structures of launch vehicles and ground infrastructure on the ground. This hidden contribution supports the satellites we rely on every day. For example, Earth observation satellites such as Sentinel-2 provide data with a resolution of up to 10 m and five-day repeat coverage. Meanwhile, Starlink communication satellites provide global connectivity for millions of users. All of this works thanks to systems in which steel provides strength and maintainability in the harsh environment of orbit and on the ground.

Steel in the Satellite Ecosystem

Behind the bright sensors and solar panels lies the “steel backbone” of the space economy. Steel is used in satellites where high strength and wear resistance are required. In satellites, steel plays critical roles, including in:

• Reaction/momentum wheel bearings;
• Deployment mechanism springs;
• Waveguide assemblies;
• Precision fasteners.

For example, AISI 440C has been the “default” for ball bearings in space mechanisms for decades. Though modern alternatives XD15NW and new NiTi-Hf alloys compete with it in terms of corrosion resistance and impact resistance. These material advances go hand in hand with broader industry changes. For instance, reusable Falcon 9 flights have reduced the cost of access to orbit, accelerating the deployment of constellations such as Starlink. On the ground, stations rely on antennas, masts, and mounts where stainless and galvanized steel remain the industrial standard. This largely invisible work of steel enables the satellite images we see from orbit and the global communication services we use every day.

The need to quickly see changes on the Earth's surface has given rise to “click-and-analyze” tools. EOSDA LandViewer combines a multi-source catalog (high-resolution optics, SAR, DEM) with cloud filters, scene and time-lapse comparisons, over 20 indices (NDVI, etc.), and GeoTIFF/KMZ export, as well as AOI alerts. In this context, it is natural to want to monitor the Earth in real-time with satellite images, as both fresh and historical data are needed. It also allows for quick comparison of changes for municipal, scientific, or business tasks. That is why transparency about data sources is so important. LandViewer collaborates with leading real-time satellite imagery providers, including ESA/USGS, as well as major commercial operators.

LEO Environment And Material Requirements

The Low Earth Orbit environment is characterized by near-vacuum conditions, intense ultraviolet radiation, exposure to charged particle radiation, rapid thermal cycles, and continuous atomic oxygen erosion.

NASA's MISSE experiments have shown that the most common approach is to use thin SiOₓ/Al₂O₃ protective films, which significantly reduce the AO erosion rate for sensitive materials and coatings.

Therefore, modern solutions combine steel grade selection, heat treatment, as well as electropolishing and barrier layers. This integrated approach allows steel components to operate reliably for decades in space. At the same time, the data channel feeds real-time satellite imagery for response and analysis services.

Modern Steels: Surface Technologies

Austenitic stainless steels, bearing steels, and precipitation-hardening steels are commonly used in satellite and launch system components, often enhanced with specialized coatings and finishes.

stainless steels for cryogenic and dynamic conditions

Types Austenitic304/304L and 316/316L retain their toughness and increase their strength as the temperature decreases. Therefore, they are widely used for cryogenic environments. They are particularly useful in applications such as:

• liquid gas storage and transportation systems;
• cryogenic pipelines and welded joints.

Separate NASA studies for 316L welded metals confirm high crack resistance down to −269 °C when process control is maintained. Steel of this class performs well in thermal cycles and cryogenic gradients of launch systems. The result is continuous real-time satellite images of Earth in observation services. 

Bearing steels in device mechanisms

The classic choice for ball bearings in reaction flywheels is AISI 440C due to its advanced characteristics:

• High hardness;
• Contact endurance;
• Geometric stability.

At the same time, alternatives are being actively tested. XD15NW demonstrates higher wear resistance. NiTi-Hf materials show corrosion resistance exceeding 440C and better impact behavior. Reliable bearings are crucial for maintaining the stability of satellite platforms, ensuring the quality of real-time Earth observation imagery.

Precipitation-hardening steels and additive manufacturing

17-4 PH is the “workhorse” for heavy-duty components. After heat treatment according to the H900 regime, typical strengths reach ~190 ksi (≈1.31 GPa) with sufficient ductility. Modern additive technologies combined with optimized heating yield results of ~1.35 GPa (UTS) and ~1.11 GPa (YS).

Here, every gram literally weighs the cost of launch. In space systems, every gram affects launch cost, so lighter components allow for larger batteries, better transmitters, and faster data transfer - directly benefiting near-real-time satellite imagery.

Coatings And Finishes: From AO Barriers To Wear Reduction

SiOₓ/Al₂O₃ coatings significantly slow down AO erosion. Combined with electropolishing and passivation, they reduce the likelihood of corrosion-mechanical damage. Functional layers such as DLC or TiN are added to tribopairs. They reduce the coefficient of friction and sticking in a vacuum. Such solutions are critical for drives that stabilize optics. This results in a clearer signal/noise image in real-time satellite view of Earth.

Applications of Steel in the Space Economy

Earth observation

Sentinel-2A/B/C satellites, with their 13 spectral channels, 290-kilometer swath width, and five-day revisit time at the equator, have become the benchmark for monitoring vegetation, water resources, and urbanization. Steel components ensure:

• Rigidity of optical modules;
• Accuracy of pointing mechanisms;
• Durability of mountings in thermal cycles.

The cumulative effect is stable, reproducible data that services transform into real-time satellite imagery and near-real-time satellite imagery for cartography, forestry, or fire response.

Satellite communications and global access

As of August 2025, there were more than 8,000 Starlink satellites in orbit. The high deployment rate is supported by multiple Falcon 9 launches. The ground network is supported by thousands of steel components. This creates an infrastructure that seamlessly captures data traffic and provides real-time satellite view services to users worldwide. 

Launches and ground segment

Steel bears the lion's share of mechanical loads in launch systems and ground infrastructure. Rocket programs that actively use stainless steel for tanks and structures demonstrate high technological readiness and maintainability. The record reusability of Falcon 9 and continuous missions to launch Starlink batches in August–September 2025 illustrate how steel reduces the cost of access to orbit. As a result, it lowers the cost of satellite images in real time, on which more than $600 billion of the global economy that relies on space services already depends. 

Steel’s Enduring Role in Satellites and Space Infrastructure

Austenitic steel grades (304/316) exhibit exceptional toughness at cryogenic temperatures. Precipitation-hardening alloys provide high contact strength and stability. Modern coatings protect against atomic oxygen and wear. Together, these innovations ensure reliable mechanisms, rigid supports, and durable fasteners. This is true for observation satellites as well as mega-constellations such as Starlink. Thanks to launch infrastructure and ground stations, where steel remains the “first line” material, the industry can fully support real-time satellite imagery and a real-time satellite view of Earth. Innovations in grades, heat treatment, and coatings mean that steel will continue to be the backbone of reliable satellite systems in Earth orbit.