CubeSat Design Specification (CDS Rev. 14.1) & PC/104 Architecture

Mechanical, electrical, and operational requirements of Cal Poly’s CubeSat Design Specification Rev. 14.1 (1U–12U), corner rail tolerances, separation switches, and the 90×96 mm PC/104 avionics stack.

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SQ-FF-007
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Purpose of the CDS

The CubeSat Design Specification (), maintained by California Polytechnic State University (Cal Poly SLO), defines the standardized mechanical, electrical, and operational contract between a U-class nanosatellite and its containerized orbital deployer[1]. Originally introduced in 1999 by Jordi Puig-Suari and Robert J. Twiggs[2][3], Revision 14.1 covers 1U, 1.5U, 2U, 3U, 6U, and 12U spacecraft envelopes and raises the baseline 1U mass limit from 1.33 kg to 2.00 kg.

Corner Rails vs. Sliding Backplates

Unlike PocketQubes—which slide on a single 1.6 mm thick baseplate tab—a CubeSat rides on four corner rails along its and edges[4]. Each rail must provide a minimum contact width of 8.5 mm and a surface roughness , per MIL-A-8625 Type III to prevent against the deployer guide rails in vacuum[1].

Envelope & Mass Table (CDS Rev. 14.1)

Form FactorX × Y Cross-Section (mm)Z Length (mm)Max Mass (kg)CoM Offset Tolerance (X / Y / Z)
1U100.0 × 100.0113.5 ± 0.12.00±20 / ±20 / ±20 mm
1.5U100.0 × 100.0170.2 ± 0.13.00±20 / ±20 / ±30 mm
2U100.0 × 100.0227.0 ± 0.14.00±20 / ±20 / ±45 mm
3U100.0 × 100.0340.5 ± 0.36.00±20 / ±20 / ±70 mm
6U226.3 × 100.0366.0 ± 0.312.00±45 / ±20 / ±70 mm
12U226.3 × 226.3366.0 ± 0.324.00±45 / ±45 / ±70 mm

PC/104 Avionics Stack Geometry

While the leaves internal layout open, most 1U–3U CubeSats adopt the industrial PC/104 board footprint[5]:

  • Board outline: () with four M3 corner standoffs.
  • Bus connector: 104-pin dual-row pass-through header ( + pins on 2.54 mm pitch), carrying unregulated , regulated 3.3 V / 5 V rails, , SPI, UART, and CAN lines.

Evolution from PC/104 to Modular Backplanes

Over 2,500 CubeSats have flown using -compliant rails. On 3U and 6U operational spacecraft, traditional pass-through PC/104 stacks are increasingly replaced by active backplanes with D-Sub or Micro-D connectors and differential CAN / RS-422 / SpaceWire buses to eliminate stack-disassembly bottlenecks during .

References

  1. [1]The CubeSat Program, Cal Poly SLO. (2022). CubeSat Design Specification, Rev. 14.1 (CP-CDS-R14.1). California Polytechnic State University.nasa.gov
  2. [2]Heidt, H., Puig-Suari, J., Moore, A. S., Nakasuka, S., & Twiggs, R. J. (2000). CubeSat: a new generation of picosatellite for education and industry low-cost space experimentation. In: 14th Annual AIAA/USU Conference on Small Satellites (SSC00-V-5).
  3. [3]Puig-Suari, J., Turner, C., & Ahlgren, W. (2001). Development of the standard CubeSat deployer and a CubeSat class PicoSatellite. In: 2001 IEEE Aerospace Conference Proceedings, vol. 1 (347–353).doi:10.1109/AERO.2001.931726
  4. [4]nadir lab. (2026). PocketQube-class picosatellites: architecture, flight heritage, and a multi-method post-flight analysis of Grizu-263A [Preprint]. nadir lab. Research Monographs (SQ-R-001).Read on nadir lab.
  5. [5]NASA CubeSat Launch Initiative. (2017). CubeSat 101: Basic Concepts and Processes for First-Time CubeSat Developers. NASA.nasa.gov(accessed 20 October 2026)

Cite this SatWiki entry

@misc{nadirlab2026cubesat,
  author       = {{nadir lab.}},
  title        = {{CubeSat Design Specification (CDS Rev. 14.1) \& PC/104 Architecture}},
  year         = {2026},
  month        = oct,
  howpublished = {nadir lab. SatWiki SQ-FF-007 (Rev. 1)},
  url          = {https://nadirlab.space/wiki/cubesat-standard-cds/}
}