Small Satellites: The Benefits of Downsizing

Small satellites offer significant opportunities and present potential space safety challenges. Their reduced size and mass can lower launch costs, speed up the process, and provide high resolution Earth images for lower fees or even for free. Many missions launch numerous small satellites, creating constellations and covering more ground. Advances in miniaturized components and propulsion allow more extended operation and higher orbits, opening new horizons in the Earth observation field.

The Sizes Of Satellites

Traditionally, satellites were large, like geostationary satellites weighing six metric tons and having a 48-meter wingspan, requiring powerful rocket launches. One of the most prominent examples here is the infamous Sentinel-2. However, advances in microprocessors, efficient solar panels, and lower launch costs have led to the creation of small satellites, or smallsats, which are now the most common satellites in orbit due to their affordability and ease of launch.

Weighing 100 to 500 kg, Minisats are ideal for cost-effective missions such as commercial remote sensing and telecommunications constellations. For instance, EOS SAT-1 and SkySat are minisats. Microsatellites weigh under 100 kg and are used in scientific research and messaging systems, benefiting from high revisit rates. the example here is NuSat. Nanosatellites weighing up to 10 kg are built to CubeSat specifications and are used for experiments, communication systems, and remote sensing. Picosats weighing 0.1 to 1 kg are used for data interchange in formation with other satellites. Weighing under 100 grams, Femtosats are used for imaging, technology testing, and biological experiments. All of those smallsats are used to extract high quality satellite images.

Practical Uses Of Small Satellites

Small spacecrafts excel in specific applications due to the downsizing of components like digital processors and sensors, though limitations exist for others. For instance, antenna aperture size restricts smallsats in telecommunications, while downsized sensors make low-orbit constellations practical for remote sensing gathering high resolution satellite data. Small satellites are mainly used for navigation, Earth observation, telecommunications, technology demonstration, and scientific research.

Freely available Earth observation data has commercial applications, helping with the disaster response and infrastructure risk assessment. Satellite data also enhances supply chain resilience and supports agriculture, forestry, fisheries, insurance, and mining sectors. Businesses need specialized skills involving AI and data science to maximize the benefits of this data. Hires satellite images offer precise detail, revealing individual trees, vehicles, and buildings. It provides on-demand coverage that is useful for targeted observations.

Advantages of Small Satellites

Most advantages of small satellites stem from their miniature nature, making them more affordable to construct, launch, and operate, thus making space exploration accessible to various organizations. Their shorter development cycles allow for faster mission deployment. Versatile and adaptable, small satellites are perfect for different missions. Their compact size and lower costs make it feasible to launch constellations, enhancing coverage and application range. The reduced overall cost risk allows for incorporating newer, untested technology. Unlike large multi-payload spacecraft, small, purpose-built satellites are more straightforward.

Three key developments unlock new capabilities for satellite observation: smaller, more powerful satellites due to commercial development, enabling technologies increasing the utility of Earth observation data, and a growing market infrastructure driven by open-source data and venture capital. Advanced sensors provide ultra high resolution satellite imagery, while cloud-based applications, machine learning, and edge AI process this data efficiently. Improved communication infrastructure enhances data transmission, including free space optical communication and better ground stations. The evolving market infrastructure combines satellite data with other datasets, offering detailed insights into enterprise operations.

Small Satellite Exploitation

Due to their higher power-to-mass ratios, small satellites can generate limited power from solar energy, with nanosats in low Earth orbit potentially producing up to ten watts. Extensible panels could double this power, but they add mass and complexity. Current standards prohibit nuclear energy in low Earth orbit. Energy storage limits nanosats to sustain one watt of continuous power for a few months or ten watts for a few days. Ground surveillance and communication depend on aperture size, with nanosats achieving limited resolution and communication capabilities. Stabilization and pointing are challenging due to low inertia, with passive techniques offering limited precision and active techniques being complex. Maneuverability is restricted by available propellants, with limited delta-V for collision avoidance. Despite these limitations, small satellites provide significant cost and deployment speed advantages that compensate for everything else regarding scalability.

In conclusion, small satellites transform space exploration and Earth observation by offering cost-effective, versatile solutions. Their reduced size and mass lower launch costs and accelerate deployment. High-resolution imaging and diverse applications, from scientific research to commercial uses, are now possible. Despite challenges in power generation, communication capabilities, and maneuverability, smallsats provide significant advantages in affordability, speed, and accessibility. These satellites enable quick deployment of missions, enhanced coverage through constellations, and integration of advanced, untested technologies. They are becoming indispensable tools for modern space missions and data-driven industries, driving innovation and expanding capabilities across various fields. 

Autor: Peter Kogut 

Petro Kogut has a PhD in Physics and Mathematics and is the author of multiple scientific publications. Among other topics, he has a specific focus on a satellite imagery processing and application in his academic research. Currently, Prof. Dr. Petro Kogut also works a science advisor.