When asked to think of a satellite, most people imagine a giant, bulky device that costs millions of dollars to manufacture and send into space. This type of spacecraft, however, might soon be replaced by a smaller and less expensive device, the Sprite.
Designed, built and tested by Zachary Manchester grad and his collaborators, the Sprite is a tiny spacecraft the size of a few postage stamps that can be built and launched into low Earth orbit for just a few hundred dollars each. A Sprite consists of solar cells, a radio transceiver and a microcontroller with memory and sensors. It has many of the same capabilities as a large spacecraft, just scaled down, but current versions are not as advanced as most other spacecrafts quite yet. “The first version can’t do much more than transmit its name and a few bits of data — think of it as a shrunken down Sputnik — but future versions could include any type of sensor that will fit, from thermometers to cameras,” Manchester said.
According to Manchester, the condensed size of the Sprite is its best characteristic, but making it functional with such size limitations was a difficult challenge. “Having something so small actually be able to send a signal back to earth was a major problem, but cell phone technology actually solved a lot of the issue for us. Cell phones these days have immense capabilities and are fairly small, and we borrowed a lot of that similar technology,” Manchester said.
Manchester also explained that the concept for a small satellite like the Sprite was first developed in the 1990s, during a general trend towards decreasing the size of consumer electronics. “People have been working on this long before us, but no one had actually built it yet,” he said.
The size of the Sprite is particularly important because it makes the spacecraft only $300 and expendable. Typical satellites are huge and very expensive to build, so the money begins to plays a major role in the project. “You don’t want anything to jeopardize your billion-dollar design so you take precautions that cost even more. You can’t really fix it once it’s out in space, so it becomes a game of chance when you count on one spacecraft to be successful,” he said.
Sprites are different however. It will be possible to send them into space in large numbers, with little concern as to whether or not some of them will survive the journey. “The idea is that rather than having this large exquisite thing, we have this cheap expendable device. Some of them will work and some of them will die, but as long as some of these survive, they’ll get the job done,” Manchester said.
The Sprites will be taken into space on a KickSat a standardized small satellite that is easy to launch. It is designed to carry hundreds or even thousands of Sprites into space and deploy them in low Earth orbit. The Sprites will be housed inside KickSat in several spring-loaded stacks and held in place by a lid. “A radio signal transmitted from our ground station will command the lid to open, releasing the Sprites as free-flying spacecrafts,” Manchester said. “After the Sprites are deployed from KickStat, we will track them and record their radio signals using a worldwide network of amateur ground stations to demonstrate their communication capabilities. We will also gather data on how long the Sprites stay in orbit and how well their electronics hold up in the harsh space environment.”
Because KickSat is launched into a low-altitude orbit, all of the Sprites will re-enter the Earth’s atmosphere within a few days or weeks, leaving no trace of space debris. KickSat itself will last somewhat longer, but should burn up in the atmosphere within a few months.
Eventually, Manchester hopes to improve Sprite technology and figure out a way to have mesh-networking capability, allowing the Sprites to collaborate with each other.
“We want them to eventually start talking to each other,” Manchester said. Manchester also wants to use the Sprites for exploration of “interesting spaces,” like the rings of Saturn. “The Sprite is special because it can enter planetary atmospheres, which allow us to take measurement of several important things. With a few tweaks, it can even enter the Earth’s atmosphere without burning up and that’s very promising,” he said.