CubeSats are modular satellites assembled from 10cm cubes. They were invented in 1999 by two Californian professors as a way for students to design scientific experiments that could be launched cheaply into orbit. They then took off for general use. By early 2026 more than 3,000 had been launched. In 2018 two of them travelled as far as Mars, though they did not land there. CubeSats are constrained by the ratio between their surface area (which limits the number of solar cells they can carry) and their volume (into which their electricity-consuming equipment is packed), leaving them systematically underpowered.
DiskSats were proposed by the Aerospace Corporation, an independent, largely government-funded not-for-profit organisation in Virginia, as an alternative to CubeSats. Each is a flat disc one metre across and 2.5cm thick, giving a higher surface-area-to-volume ratio. This allows them to carry bigger aerials and more solar cells. Their flat shape also fits efficiently inside rocket fairings and, by flying edge-first, they present a narrow profile to the atmosphere, reducing drag and allowing them to stay aloft in lower orbits where atmospheric resistance is a consideration.
The first four DiskSats were launched on December 18th 2025, carried in an Electron rocket built by Rocket Lab. Two are planned to descend to very-low-Earth orbit, below 300km, to test their performance in thicker atmosphere. The mission was sponsored by America's Space Force; the lower a satellite can go, the better its view of Earth's surface.
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