CubeSats: Sending Paperweight-Sized Satellites To Space

By John Oncea, Editor

CubeSats – small, low-cost satellites – can be used for many purposes, from monitoring environmental changes to detecting and assessing disasters and more. For around $7,500 you can own one of these picosatellites and, for another $40,000 or so, hitch a ride on a rocket and conduct experiments in space!

CubeSats, small satellites that can be built using inexpensive off-the-shelf electronics and standardized components, can be launched into space equipped with solar panels, antennas, a computer, and an orientation system. Some of these small satellites, known as Кубсат in Russian, even have engines for maneuvering.

Over the past 25 years, CubeSats have made it easier and cheaper to access space, shaking up the space industry along the way. “Having initially been developed as educational tools, CubeSats are increasingly being put to active use in orbit for technology demonstration, scientific studies, and even commercial purposes,” writes the European Space Agency (ESA). “And just like typical satellites, they are custom-built to fulfill the specific requirements of their mission.”

Let’s take a look at these little beauties, from their humble beginnings as educational tools to their use today for technology demonstrations, scientific studies, and commercial purposes.

25 Years Getting To Get Where We Are

CubeSats are, according to NASA, a class of nanosatellites* that use a standard size and form factor of “one unit” or “1U” measuring 10x10x10 centimeters and are extendable to larger sizes; 1.5U, 2U, 3U, 6U, and even 12U. “The development of CubeSats has advanced into its own industry with government, industry, and academia collaborating for ever-increasing capabilities. CubeSats now provides a cost-effective platform for science investigations, new technology demonstrations, and advanced mission concepts using constellations, swarms disaggregated systems.”

Like many technologies, CubeSat’s beginnings can be traced to academia, specifically California Polytechnic State University and Stanford University. Professors Jordi Puig-Suari (Cal Poly) and Bob Twiggs (Stanford’s Space Systems Development Laboratory) developed the CubeSat specifications from a project at the Aeronautics and Astronautics Department that Stanford University had with Defense Advanced Research Projects Agency (DARPA) and the Aerospace Corporation in 1998.

“The Aerospace Corporation wanted to launch a little satellite (picosat) the size of Klondike ice cream bar as part of a DARPA program,” writes Science Direct. “The graduate engineering students at Stanford that had been working on microsats since 1995 decided that it would be challenging to build a launcher for this little picosatellite.”

So instead, they designed a deployer, built like the cartridge holder for a gun, that was capable of fitting inside a microsatellite. The microsat was called Orbiting Picosat Automated Launchers (OPAL) and it launched in 2000 with the picosats intact. Everything went as planned, DARPA was satisfied, and it was deemed feasible for students to work on smaller satellites like picosats which evolved into the CubeSat.

“The design challenge was to make something like this little picosat that was like the size of an ice cream bar and a launcher that could launch several of them at once,” writes Science Direct. “But, to make them useful, more solar cells (were needed which) could only be mounted on the flat sides of the picosat. That need led to the thought of making the picosat in a cube shape.”

Two by four-centimeter solar cells were donated by JPL and it was determined that a four-inch cube was the optimal size to still have a method of holding the cube in the launcher. Researchers went to a local plastic shop to find a model for the cube and selected a beanie babies display case that was four inches.

“The method of holding the picosats was by the corners that were chamfered,” Science Direct writes. “In the picosat, they were secured in the launcher only by the force of the launcher door. It had worked for the picosats, so this same method was used with the CubeSat deployer.

“Being held by the corners with 10 one-thousands clearance, it would not move significantly during vibration. A quarter inch was allowed on the edges for the rails. To have multiple CubeSats in a launcher would require some way to separate the cubes.” The solution was quarter-inch plastic cubes that were put on the ends of the four-inch cubes to keep the adjacent cube faces from contacting, later called separation feet.

The researchers were using English units of measurement, but the aerospace industry used metric units leading to the conversion from “four-inch” cubes to “10-centimeter” cubes. At the same time, the accepted aerospace definition for a picosat was 1 kilogram and a 10-centimeter cube filled with water weighs a kilogram leading to the standard mass allocation. And that was how the CubeSat was created.

Being small, lightweight, and inexpensive aren’t the only attributes of CubeSats, according to GIS Geography. They are quick to develop and easy to maintain and can be built from commercial off-the-shelf components which helps make them modular, scalable, and ideal for different missions and purposes. Due to this, they are a low-risk investment that can easily be launched into Low Earth Orbit via the International Space Station. According to NASA, $300,000 is typically enough to launch a 3U into low-Earth orbit (CSLI).

“Although there are advantages mostly related to cost and size, cube satellites also face various challenges,” GIS Geography writes. “They have little or no propulsion, so you can’t control where they go. Because you need a way to move, mini propulsion systems add extra cost.” In addition:

• Failed launches are more common compared to traditional satellites
• Because of their smaller dimensions, it limits their operational lifetime
• It’s uncommon for nanosatellites in Medium Earth Orbit (MEO), Geostationary orbit (GEO), and highly elliptical orbit (HEO)
• Nanosatellites have a shorter lifespan compared to traditional satellites and can remain in orbit sometimes for no longer than a year

* “In mass-classification and strict terms, a nanosatellite is any satellite with mass from 1 kg to 10 kg,” writes Nanosats Database. In their database, “’Nanosatellite’ covers all CubeSats, PocketQubes, TubeSats, SunCubes, ThinSats, and non-standard picosatellites, unless otherwise stated.”

An Orbiting Internet And More

CubeSats are being used to track disasters and monitor climate change. They are also being used to deliver reliable internet access to not only developing nations but even parts of North America, reports GIS Geography.

“Remote regions, where connectivity can be expensive or difficult to acquire, and locations that are off the beaten path are some of the challenges that will continue to make the internet more difficult to access. CubeSat constellations are one way to bring satellite access and connectivity to difficult-to-reach locations. Small satellites are a promising tool for delivering internet access to remote areas that suffer from a lack of connectivity.”

Beyond that, according to TS2 Space, “The use of CubeSats is changing the way we explore space, as they are much more accessible than traditional satellites. They are also a key factor in the advancement of space exploration and research, as they allow us to access space at a fraction of the cost. As the technology continues to develop, CubeSats are sure to revolutionize the way we explore space even further.”

SpaceX and other private companies are already planning to use CubeSats for deep space exploration, with some aiming to reach Mars. CubeSats are also being incorporated into the study of other planets and moons, giving scientists an unprecedented understanding of their composition and atmosphere. They could even help search for signs of life on other worlds.

In addition, CubeSats are expected to play an important role in the commercialization of space. They could be used to conduct zero-gravity experiments or to monitor the performance of commercial satellites. They could even help build large-scale infrastructure in space, such as space elevators or solar power satellites.