Apogee Staff
Its inventors were thinking small when they hit on something big 25 years ago. Now-retired Stanford University Professor Bob Twiggs and Jordi Puig-Suari, a former aerospace engineering professor at California Polytechnic State University, had no inkling their idea, the CubeSat, would spur interest among researchers worldwide.
The miniature satellites, which rely on a standardized “one unit,” or “1U,” parameter of 10 cubic centimeters, about the size of a Rubik’s Cube, are now commonly used by governments, universities, private industry and numerous other organizations.
The satellites can be expanded to 1.5, 2, 3, 6, 12 and even 16Us and made to operate alone or in a constellation. They generally weigh as little as a kilogram, but even at their largest they pale in comparison to their older cousin, the SmallSat, which can be the size of a refrigerator and weigh up to 180 kilograms.
Twiggs’ and Puig-Suari’s platform started life in 1999 as a teaching tool to give Cal Poly graduate students experience in satellite functionality. The spacecraft soared in popularity after researchers around the world heard about the technology and realized that its small size and hallmark standardization could pave the way for multiple types of efficient, affordable spacecraft. Also enticing, many of its components could be sourced “off the shelf” to lower costs even more.
In an interview with Cal Poly magazine in 2022, Puig-Suari described the satellites as a kind of “sandbox” where industry can explore various avenues of space-based research. “Faster, smaller, taking more risk and leveraging the technological developments of non-space industries, such as the commercial electronics sector — those new ways of doing business that were introduced by CubeSats form the basis of many of the new missions being developed by space companies,” he said.
Puig-Suari, who retired from the university in July 2018, and co-inventor Twiggs were inducted into the Space Technology Hall of Fame in April 2022 during the 37th annual Space Symposium in Colorado Springs, Colorado. Their invention has served as the basis for numerous studies and missions by universities, companies and governments. According to the NanoSats Database, the world’s largest online database to track CubeSats, 2,396 CubeSats have been launched into space as of May 31, 2024.
Notably, on February 15, 2017, the Indian Space Research Organisation set a record with the launch of 104 satellites aboard a single rocket. Of that number, all but three were CubeSats. Together, the payload amounted to just over 650 kilograms.
CubeSats are deployed regularly from the International Space Station and have been associated with multiple scientific studies. Among them was the May 2018 InSight mission to Mars. The robotic Mars lander included two CubeSats – known as Mars Cube One (MarCO) A and B – designed to fly by the planet to provide relay communications from InSight to Earth during entry and landing. This marked the first flight of CubeSats not only to Mars but also in deep space.
After separation, the 13-kilogram spacecraft deployed two solar panels and two radio antennas to send real-time communications to Earth. They navigated to Mars independently of the InSight lander, making their own course adjustments. InSight successfully landed on Mars on November 26, 2018, maintaining communications with Earth until December 15, 2022.
CubeSats have punched above their weight for years. As part of the November 2022 Artemis I mission to the moon, 10 CubeSats were deployed during various stages to conduct experiments vital to the upcoming astronaut mission, Artemis II, in September 2025. Other CubeSats have operated well beyond their life expectancy, surprising researchers.
The Colorado Ultraviolet Transit Experiment (CUTE), a CubeSat equipped with a telescope to send data to a spectrograph, was designed to travel in sun-synchronous low Earth orbit for eight months. However, two years later, the spacecraft is still operating. According to a December 2023 article in SpaceNews, CUTE launched in September 2021 as a secondary payload on the NASA-U.S. Geological Survey Landsat 9 Earth-observation mission. Twenty-seven months later, its onboard instruments were still observing atmospheric loss of “hot Jupiters,” gas giants that orbit very close to bright stars.
The budget, meanwhile, to develop, build and operate CUTE through the summer of 2024 has amounted to a relative bargain compared to most satellite programs, about $5.5 million, Kevin France, CUTE principal investigator at the University of Colorado’s Laboratory for Atmospheric and Space Physics, told SpaceNews. “CUTE’s been a great success, particularly given that we didn’t really know if we could do it for the amount of money that we proposed,” he said.