Miniature satellites are driving a new wave of innovation in space systems and are generating excitement similar to that of the earliest days of space exploration. The global small satellite market is expected to grow to more than US $7.5 billion by 2022, according to Market Watch.
The tiny satellites are taking on increasingly complex missions. In May the Jet Propulsion Lab–Caltech Mars Cube One mission sent two CubeSats to fly alongside NASA’s InSight lander on its way to Mars. The pair, the first microsatellites to support a deep space mission, are designed to relay data back to Earth this month when InSight reaches its destination.
Small satellites are allowing commercial enterprises and educational institutions to perform space missions. Universities in Africa, China, Europe, India, and the United States have launched and operated small satellites, which are a fraction of the cost of traditional satellites that can weigh more than 1,000 kilograms and cost millions of dollars to launch. Some models are as small as the 10-square-centimeter CubeSat and weigh as little as 1.5 kg.
Miniature satellites leverage advances in computation, miniaturized electronics, and packaging to produce sophisticated mission capabilities. Because the microsatellites can share the ride to space with other missions, they offer private companies, government space agencies, and universities a more affordable way to make observations about the Earth, conduct research, and test components and systems.
A number of commercial operators are envisioning large constellations of small satellites to open up markets for low-cost data communication, earth observation, and other services.
In “Modern Small Satellites—Changing the Economics of Space,” published in the Proceedings of the IEEE, Member Martin Sweeting covers the history of small satellite development.
“Although microsatellites are physically small, they are nevertheless complex vehicles that exhibit virtually all the characteristics of a large satellite,” Sweeting says. “This makes them particularly suitable as a focus for education and training of scientists and engineers by providing them with hands-on experience at all stages of a real satellite mission—from design, production, test, and launch through to orbital operation.”
Miniaturization comes with tradeoffs, though, he says. Small satellites that use commercial off-the-shelf components are cheaper to build, faster to upgrade, and financially less risky if they don’t work as expected. But their capabilities are limited.
Miniature, short-lived satellites, which are traditionally launched into a low Earth orbit, are nothing new, Sweeting says. The history of small satellites is as old as space exploration itself, dating back to the first Earth satellite, Sputnik 1. Launched by the Soviet Union in 1957, it weighed 83 kg and had a radio transmitter, batteries, a remote switch, and a fan. The first U.S. satellite, Explorer 1, launched in 1958. It weighed 14 kg and carried a cosmic-ray detector, temperature sensors, and a microphone.
The first nongovernment small satellites were built by amateur radio operators who wanted to extend their hobby into space. The first amateur radio satellite, Oscar 1, was a secondary payload aboard the Thor-DM21 Agena B, launched in 1961 from Vandenberg Air Force Base, near Lompoc, Calif. The 30- by 25- by 12-centimeter box weighed 10 kg and was the world’s first satellite to piggyback on a launch. Despite its size, Oscar 1 included an antenna, batteries, and a transmitter and engaged the imagination of radio amateurs around the world.
In the 1980s, small-satellite builders began to include reprogrammable microcomputers to enable them to reconfigure capabilities remotely. Amateur radio operators were the first to include such computers, which they were already using on the ground in their communications equipment. The first to launch was the 54-kg UoSAT-1, built in 1981 at the University of Surrey, England. More were launched throughout the 1980s and 1990s, including Amsat-Oscar 10, Fuji-Oscar 12, and UoSAT-2.
In the mid-1980s, the U.S. Defense Advanced Research Projects Agency started the LightSat initiative to reduce the costs and development time of spacecraft in the 50- to 1,000-kg range, according to Sweeting. The Global Low Orbit Message Relay microsatellite was the first developed under the program. Its goal was to demonstrate the feasibility of building a two-way, digital data communication satellite capable of performing important military missions in less than a year and for less than $1 million. It weighed 62 kg, was launched in 1985 from the Challenger space shuttle, and operated for 14 months.
Despite such efforts, many observers still doubted the mission utility of microsatellites, Sweeting says. Larger satellites were becoming more impressive, and microsatellites were seen as an unwelcome distraction. But it wasn’t long before private businesses, space agencies, the military, and universities recognized the small satellites’ potential.
“Small satellite missions will not replace large satellite missions, as their goals and issues are different,” Sweeting says. “Rather, they complement them.”
A POPULAR NEW CLASS
A big boost to the small satellite industry occurred in 1999, when California Polytechnic State University and Stanford introduced CubeSats so graduate students could rapidly build nanosatellites with standardized interfaces. CubeSats are made up of one or more modules of 10 cubic cm units, each with a mass of about 1.5 kg.
The two universities also developed the Poly-Picosatellite Orbital Deployer and the QuadPack 2 multideployer, Sweeting says. The systems demonstrated the interfaces and mechanisms required to support the safe launch of CubeSats as ride-along payloads.
The first CubeSats were launched in 2003 on a Russian Eurockot. To date, more than 800 CubeSats have been sent to space. They have tested navigation and control technologies that could make space experiments more affordable, for example, and demonstrated the feasibility of tracking a nearby spacecraft with an off-the-shelf automobile anticollision system.
Small satellites are enabling new applications and business models, just as their terrestrial counterparts—the laptop and smartphone—have done, Sweeting says.
“The emerging ‘NewSpace’ sector is vibrant, innovative, and with strong potential to change the face of the space industry and the space-enabled services for the greater benefit of the global population,” he says.
Sweeting’s article is open access and can be downloaded for free from the IEEE Xplore Digital Library.