3U CubeSat bus · in design

A 3U satellite built around the picture.

Our 3U packages the star camera and image processing our payload introduced with power, pointing and communications, in one spacecraft. The lower part is a payload bay; the upper part is the bus.

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Illustration of the 3U satellite in orbit with two double-leaf solar wings deployed
Architecture

What is inside the 3U.

The design baseline as of September 2026. Power, thermal, interfaces and flight qualification are still being worked.

Payload bay
The lower part of the satellite, about 1.7U long in the current layout, holds the payload. A divider plate separates it from the bus above.
Star camera inside the body
The star camera sits fully inside the body and looks out through a side window, angled 25° from zenith. Its field of view is checked in CAD to clear the deployed solar wings.
Dedicated processing
The star camera and the main imager each get their own FPGA + ARM processor, and a separate flight computer runs the spacecraft.
Three-axis pointing
Three orthogonal reaction wheels and three magnetorquers with an attitude controller, packed into a compact cluster.
Power
Two body-mounted solar panels and two deployable wings of two leaves each, feeding a maximum-power-point-tracking power system and battery.
Communications
A UHF/VHF radio for telemetry and commands, and a separate S- or X-band radio for imagery, sized for 1 GB of compressed imagery a day.
Views

Outside, up close and inside.

Illustration of the 3U with both solar wings deployed
Illustration: two double-leaf wings deployed.
Illustration of the star camera seen through the 3U's side window
Illustration: the star camera looks out through a side window.
Illustration of the 3U's internal stack
Illustration: bus above the divider, payload bay below.
Why build the bus

The camera, the computer and the spacecraft share one design.

A payload that carries its own precision still needs a spacecraft. Building the bus as well means the star camera's attitude reaches the image processor without crossing a supplier interface, and the payload bay is laid out around the optical paths from the start.

The star camera moved inside the body in this revision. It used to stand proud of the side wall; now it looks out through a window, and the solar wings are angled slightly forward to keep its view clear.

How the star tracker works
Illustration of the 3U satellite's internal layout: the bus stack above a divider plate, the star camera and imager in the payload bay below

Illustration based on the September 2026 design study. Flight hardware will differ.

Development path

Where the 3U is today.

  • 3U design baseline

    Internal star camera, compact bus and a payload bay of about 1.7U in the current layout.

    In design

  • Stratos-2

    Validates the star camera, intelligent imaging and passive radiative cooling technologies.

    Upcoming

  • On-board stacking

    First on-board stacking flight.

    Planned
Mission details
Questions

3U bus FAQ

Is the 3U bus available to order?

It is in design. Talk to us about missions from 2027 onward.

How much room is there for a payload?

About 1.7U of the satellite's length in the current layout, below a divider plate. It is a design allocation; the certified usable volume comes later.

How much imagery can it send down?

The imagery radio is being sized for 1 GB of compressed imagery a day, separate from the telemetry and command radio.

Does it use your star camera?

Yes. The star camera sits inside the body and looks out through a side window, and its attitude feeds the imaging chain.

Work with us

Plan a mission with us.

Tell us what you want to image and when you want to fly.

Start a conversationEmail the team