by | Jul 12, 2021

What Is A Smallsat?


Smallsats are revolutionizing the way we leverage space as a resource and have been a driving force in the new space revolution.

Here on planet Earth, we are on the brink of a massive shift in the space industry, where the growing commercialization and democratization of space are bringing new information with incredible uses to every industry, from energy and agriculture, to finance, government, human rights, defense and more.

Part of that shift is the growing use and advancement of small satellites (smallsats).

While there is no official or established standard for a smallsat, the term typically refers to spacecraft with a mass of less than 500 kg, though some within the industry consider the threshold to be less. Within this category there are several classifications of smallsats.

  • Nanosatellites are spacecraft with a mass of 1-10 kg.
  • Microsatellites are spacecraft with a mass of 10-100 kgs.
  • Minisatellites are spacecraft with a mass of 100-500 kgs.
  • CubeSats are the only class of smallsats with a more clearly defined standard. A CubeSat is made up of units – one unit is a 10x10x10 cm cube. The CubeSat is then defined by the numbers of units, such as 6U or six units.

Similar to computers during the technology revolution, satellites continue to shrink in size; however, their capabilities are becoming more effective as technology advances. We are seeing smallsats execute revolutionary missions that are changing the way we see our planet, enabling us to leverage space for continued research and exploration.

Why develop smallsats?

Smallsats are significantly more cost effective than larger spacecraft and easier to produce, making them better suited for constellations. Constellations, groups of satellites working together as a system, are enabling new technologies and applications, including BlackSky’s global monitoring service. Without access to frequent images and information collected through our constellations of smallsats, we would not be able to identify, analyze and deliver timely insights.

What orbits are used?

The orbit on which a satellite is placed is dependent on the satellite’s mission, but the most common orbit for smallsats is Low Earth Orbit (LEO).

The popular LEO has an altitude somewhere between 160-320 kilometers above the Earth – a relatively low altitude. Its proximity to the Earth provides a handful of advantages, including better positioning for capturing images, contacting the satellite, and allowing for a more straightforward deorbit process (the atmospheric drag that pulls the satellite into the atmosphere, causing it to burn up). One complete orbit in LEO takes about 90 minutes.

Another key advantage to LEO is the availability of launches from Earth. As a common orbital destination, there are typically more launches available, which is helpful when trying to launch a large number of satellites for a constellation.

Sun Synchronous Orbit

Another useful orbit is the Sun Synchronous Orbit (SSO). SSO is a polar orbit, meaning it passes over the North and South Poles, and typically has an altitude of about 600-800 km, so slightly more distant than LEO. The name Sun Synchronous describes the fact that the satellite constantly remains in sunlight, making it appealing for Earth imaging satellites. However, it also means that the spacecraft will pass over the same part of the Earth at about the same time each day, limiting the variety of images collected of one location – which explains why the world has never seen a satellite image of the Super Bowl! However, with growing constellations of satellites on varying orbits, capturing an image of this should be a reality soon.

Understanding Orbital Inclination

If some satellites are capturing images of the same place at the same time, how do we capture images of the rest of the globe? Different orbital inclinations.

An orbital plane describes the shape and orientation of an orbit. So, if a spacecraft is orbiting the Earth inline with the equator, it has an inclination of about 0 degrees. The Sun Synchronous polar orbit has an orbital inclination of about 90 degrees.

What does that mean for image capture? According to NASA, “Just as different seats in a theater provide different perspectives on a performance, different Earth orbits give satellites varying perspectives, each valuable for different reasons. Some seem to hover over a single spot, providing a constant view of one face of the Earth, while others circle the planet, zipping over many different places in a day.”

Just as different seats in a theater provide different perspectives on a performance, different Earth orbits give satellites varying perspectives, each valuable for different reasons.


How are smallsats manufactured?

The simple answer? Quickly and cost-effectively – smallsats are being manufactured at a much faster pace than traditional large satellites.

This change of pace is due to the smaller size of the spacecraft, the utilization of more commonly used, off-the-shelf equipment and parts, and an efficient approach to manufacturing. Each of these items also contributes to the cost-effectiveness of the manufacturing process.

Remember how the assembly line transformed the way cars are made? This approach is being applied to smallsat manufacturing, which is how organizations can now construct 20, 30 or 40 satellites in a year.

Smallsats are also taking a page out of the smartphone playbook. Most smallsat constellations launch one or two satellites to execute pathfinding missions, which allows organizations to study and observe the satellite’s performance. Based on the findings from those initial missions, the satellite developers may choose to make changes to future models, gradually updating features of the satellites, similar to releasing a new version of the same phone. Additionally, once on orbit, software updates can be applied to satellites, improving capabilities.

How are smallsats using artificial intelligence (AI) and machine learning (ML)?

Smallsat constellations are collecting enormous amounts of data and imagery, which, when downloaded to Earth, require mammoth data analysis.

In order to understand and interpret this universe of data, many organizations are relying on the power of artificial intelligence (AI) and machine learning (ML) to reduce the data volume and/or processing time. AI and ML are well suited and equipped for handling complex, ambiguous and changing content.

Many organizations are now incorporating AI and ML for a variety of uses, such as data processing, monitoring telemetry and space-to-Earth transmissions. These emerging technologies possess the ability to process and detect patterns or anomalies throughout the complex process of reaching space and leveraging it to better understand our planet and beyond.
AI and ML are still young, budding technologies and how space organizations leverage these technologies will continue to evolve and enable new advancements. We anticipate AI and ML will continue to have a significant impact on the space industry.



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