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About PROBA-1


The Project for On-Board Autonomy-1 (PROBA-1) was originally a technology demonstration mission of the European Space Agency, started in mid-1998 and funded within the frame of ESA's General Support Technology Programme.

Intended as a one-year mission, this small satellite - less than 1 cubic metre in size - has provided data since its launch on 22 October 2001 and is still operational today, although data from its primary sensor CHRIS was suspended in December 2022.


OrbitLEO Sun-synchronous
Orbital Parameters681x561 km
Swath Width14 km
Orbit Height615 km
Orbital Plane Inclination97.9 degrees
Orbital Period96.97 minutes
Repeat CycleApprox. 7 days



PROBA-1 rolls in its orbit to take images: the satellite's platform and payload work as one: spinning reaction wheels guided by a star tracker roll it up to 25º side to side and ±55º/±36º along its path. This helps PROBA-1 to compensate for its 7.5 km/s speed, like a photographer panning to snap a moving target. So each target can be seen on up to five different angles (-55º, -36º, nadir view, +36º and +55º).

PROBA-1 Objectives

The objectives of PROBA-1 are:

  • In-orbit demonstration and evaluation of new hardware and software spacecraft technologies
  • In-orbit demonstration and evaluation of onboard operational autonomy
  • In-orbit trial and demonstration of Earth observation and space environment instruments.

PROBA-1 Instruments

The Compact High Resolution Imaging Spectrometer (CHRIS) is the prime PROBA-1 instrument, used to explore the capabilities of imaging spectrometers on agile small satellite platforms.
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The High Resolution Camera (HRC) is a black and white camera with a miniaturised telescope, studying Earth, it also returns data on its own immediate environment.
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