These disk-like spacecraft are not science fiction, and this morning, they successfully entered orbit under the watchful observation of NASA and the U.S. Space Force. Thursday morning, four DiskSat spacecraft launched on a Rocket Lab Electron rocket from Wallops Island, Virginia, with this being the first orbital demo of a novel small satellite bus solution. The Aerospace Corporation has designed this novel disk-like satellite bus solution with the promise of disrupting the dominance of the field of the CubeSat structure.
Each DiskSat has a width of 1 meter and a thickness of just 2.5 centimeters, not unlike a supersized, space-certified frisbee. Its exterior is actually made of carbon fiber composites, while its core and other electronics feature a lightweight aluminum honeycomb structure. DiskSats provide a power-to-weight ratio that is millions of percent greater than would be achievable in a comparable mass satellite fashioned out of standard aluminum, according to Aerospace engineers, who claim five to ten times greater power generation for a comparable mass to a CubeSat. Each DiskSat tips the scales at 16 kilograms, which is under half the mass of a standard 12U CubeSat, yet has over 13 times as much real estate on one face hitting the jackpot for massive antennae, radar, and communication equipment.
This launch also demonstrated a bespoke dispenser design that placed each of the four satellites in a 550-kilometer orbit. Subsequent maneuvers will allow ground controllers to initially lower these satellites gradually through the thinner regions towards the lower regions of the upper atmosphere in hopes of reaching below 400 kilometers in altitude or even as low as 200 kilometers. This is recognized as “very low Earth orbit” where greater resolution images, faster communication signals, and greater received signal strength are feasible as a result of satellites being much closer to Earth. Sensing range capability in radar satellites can improve eightfold.
VLEO operations, on the other hand, are a material and propulsive concern. Highly enriched in atomic oxygen, the environment corrodes most spacecraft surfaces. Aerodynamic forces are also significant enough to lead to rapid orbital decay. The orbital plane of DiskSat, which remains in an edge-on orientation, provides a low drag efficiency. On the other hand, the use of electric propulsion, which relies on the extensive solar array power, provides a constant reboost. Just like the latest air-breathing electric propulsion designs, such a system remains critical and highly relevant to the success of VLEO missions.
Materials selection becomes an important factor under such conditions. Carbon fiber composites have excellent stiffness and lightness but pose anisotropic expansion properties that may likely cause stress fractures during the severe temperature cycling on orbit from +121°C in sun to as low as -157°C in shade every 90 minutes. The DiskSat’s carbon fiber structure may help to improve the weaknesses associated with the weights and stiffness requirements but may advance to the use of new polymers such as HX5®, which have a radiation resistance level of up to 5 million rads and could provide minimal outgassing and specific expansion properties.
From a technical perspective, their flat, stackable form factor is a huge plus in terms of logistics systems. Much like SpaceX’s Starlink satellites, DiskSats can be launched densely, allowing a constellation-scale launch in a single mission. This is scalable enough to support defense missions in which dozens or hundreds of high-powered, low-mass satellites may be launched together in a single mission to provide surveillance, communication, or missile defense capabilities. The Space Force is clearly intrigued, as VLEO constellations can provide them with near-real-time intelligence, airborne sensor integration, and a ‘self-cleaning’ orbit that naturally de-orbits in a matter of weeks.
The DiskSat mission will not only test the maneuverability and power output capabilities, but the challenges associated with the disc size, such as thermal management, structural robustness, and pointing precision, will also be analyzed. Although experts confirm that the advantages offered by the greater surface area outweigh those of the size, when it comes to thermal control and aggressive pointing, cubes and cylinders have a clear edge. This will ultimately decide whether the system will be a niche offering or a mainstream alternative to the traditional CubeSat. If this goes on, The Aerospace Corporation will transfer this technology to commercial manufacturers. Given the projected market in VLEO at $220 billion by 2027, with defense sectors around the world vying to unlock the potential offered by this orbit, DiskSat might make its appearance at a critical juncture. Its power, mass, and packing density make it a likely leader in the next generation of orbital platforms, no matter what their applications the Earth observation, communication, or defense sectors.
