European Space Agency

T3 Star Tracker - T3 Compact Star Tracker


The objectives of the project are to develop a very compact star tracker targeting the increasing market for small satellites.


The primary challenges faced during development of the T3 Star Tracker is to meet the very low physical envelope and power budget placing it as a strong candidate in the small satellite market.


The T3 Star Tracker will fit into an envelope of 60x60x100 mm while maintaining a total power consumption of less than 1W.


The T3 Star Tracker can provide attitude estimates at 5 Hz with an accuracy exceeding 2 arcseconds even under slew rates up to 1.5 deg/s.

System Architecture

Decomposing T3, it consists of a focal plane (with the sensor) and a computer in a single housing, with optics and baffle mounted on top.


The project consists of the following overall phases:

  1. Trade-Off & Consolidation Phase
  2. Design Phase
  3. Manufacturing & Test Phase

With phase transitions governed by the following reviews:

  1. Mid-Term Review
  2. Preliminary Design Review
  3. Final Review

Current status

Work is currently taking place in the Trade-Off & Consolidation Phase approaching the Mid-Term Review.

Status date

Friday, March 22, 2019 - 10:40