Is 2-D the Future of Small Satellites?
CubeSats are defined by their containerization — the shape, volume and design that enables ridesharing without endangering a launch vehicle or primary payload. With small satellite constellations in Low Earth Orbit now performing the functions of larger satellites, is the traditional CubeSat still the best design for every mission?
The answer to that question may lie in a two-dimensional DiskSat, a NASA Small Spacecraft Technology program funded concept that may expand SmallSat mission designs and enable major scientific discovery at lower cost.
The concept for DiskSat originated when Richard Welle, Aerospace Senior Scientist took part in a study of large constellations using CubeSats. The team quickly recognized the mission would need additional power and more aperture than a CubeSat could provide. Placing the constellation in well-defined orbits would also require dedicated small launch vehicles.
Without the need for rideshare, Welle realized that satellite design options could be expanded beyond a standard CubeSat. The plate-shaped DiskSat satellite at 1m diameter and 2.5 cm thick, could provide the required power and aperture while still allowing 20 or more satellites to be containerized in a single small launch vehicle.
“The concept comes from a CubeSat world, so there are a lot of similarities,” said Welle. “DiskSat gives you the benefits of a standardized launch interface, low launch costs and simple mechanical design.”
Missions involving radio frequency and other types of signaling could benefit from DiskSat’s larger surface area. The high power and low mass make electric propulsion for maneuvering an ideal option. And while typical satellites do not operate below 300–400 km in altitude, DiskSat’s low drag means it can operate down to about 200 km with electric propulsion, providing better resolution and sensitivity. Welle estimates that a DiskSat could be placed into orbit for the cost of a 3-unit (3U) CubeSat with greater capabilities.
“With DiskSat, the payload is no longer volume constrained,” says Thomas Paige, Aerospace Senior Project Engineer, “this promises a variety of improvements including shorter design, build, integration and test schedules as well as lower costs.”
With NASA support, a demonstration mission for four spacecraft in Low Earth Orbit (LEO) is being planned to validate baseline DiskSat performance and its launch dispenser mechanism — the latter being a key goal since dispensing must be done in a way that prevents contact between satellites. The four demonstration satellites will have electric propulsion and operate in pairs. One pair will fly at low altitude, while the other will demonstrate high-altitude operations and showcase DiskSat maneuverability.
Beyond LEO and Earth science, there is potential for DiskSat to perform in lunar communications and resource mapping missions. The DiskSat concept was presented at the recent Small Satellite Conference hosted by Utah State University.
Originally published at aerospace.org on August 11, 2021.