CubeSats have changed the space industry. Universities, start-ups and established companies use them for technology tests, Earth observation and communication. The reason is a simple, shared standard that makes building and launching small satellites predictable.
What is a CubeSat?
A CubeSat is built from standard units. One unit, called 1U, is a cube with an edge length of 10 cm. The CubeSat Design Specification, maintained by California Polytechnic State University (Cal Poly), defines the dimensions, the maximum mass per unit and the interface to the deployer. Because every CubeSat follows the same outer rules, launch providers can integrate satellites from many customers into standard dispensers.
Common sizes
- 1U to 3U: typical for university projects and first technology demonstrations.
- 6U: a popular format for commercial Earth observation and communication payloads, with more room for instruments and power.
- 12U: the largest configuration covered by the CubeSat Design Specification, used for more demanding missions that need larger optics, more power or propulsion.
More details on frames, rails and materials are in our article on CubeSat structure.
How CubeSats send their data to Earth
A CubeSat sends its data by radio to ground stations. According to NASA’s Small Spacecraft Systems Virtual Institute, VHF and UHF are the most mature bands for CubeSat communication, but in recent years there has been a shift towards S-band and X-band, with Ka-band also being used. Tracking, telemetry and command typically use S-band. Higher bands allow more data with smaller antennas but require more precise pointing. More details are in our article on satellite frequency bands.
How CubeSats get to space
CubeSats almost never fly alone. They are placed in a dispenser, which protects them during launch and pushes them into orbit with a spring once the rocket or station releases them. The main routes are:
- Rideshare missions on larger rockets, which carry dozens of CubeSats at once.
- Small launchers, which can deliver a group of CubeSats to a specific orbit.
- Deployment from the International Space Station: CubeSats travel to the station as cargo and are then released by a small satellite deployer, as the cover image of this article shows.
What operators should plan early
Launch slots for popular orbits are booked well in advance. Operators should define the target orbit, the CubeSat size and the planned launch window early and check which dispensers a provider supports. With Carrier Space you can compare suitable launch options and send a request.
Frequently asked questions
How big is a 1U CubeSat?
According to the CubeSat Design Specification (Revision 14.1, February 2022), a 1U CubeSat is a 10 cm cube with a mass of up to 2 kg.
Who defines the CubeSat standard?
The CubeSat Design Specification is maintained by the CubeSat programme at California Polytechnic State University (Cal Poly).
How do CubeSats get into orbit?
CubeSats fly inside a dispenser, usually on rideshare missions, on small launchers or as cargo to the International Space Station, from where they are deployed.
Can a CubeSat be heavier than the standard mass?
The specification notes that larger masses may be evaluated on a mission to mission basis and that operators should verify constraints with the dispenser or launch provider.
Related reading
- Rideshare or Dedicated Launch? How Small Satellites Get to Orbit
- Payload Fairings, Adapters and Separation Systems: The Launch Interface Explained
- Satellite Environmental Testing: Vibration, Thermal Vacuum and More
Sources
- Cal Poly CubeSat Laboratory, CubeSat Design Specification: cubesat.org
- NASA, image iss074e0301636: images.nasa.gov
- Cal Poly, CubeSat Design Specification Rev. 14.1 (February 2022), PDF
- NASA Small Spacecraft Systems Virtual Institute: Communications
Cover image: A trio of CubeSats built by college students is deployed from a small satellite deployer outside the International Space Station, 3 February 2026. Image: NASA, images.nasa.gov.