Project for On-board Autonomy (Proba)

A European imaging mission

Proba is a European Space Agency (ESA) satellite that was only designed with a one-year life span. It recently celebrated its sixth anniversary in space and has produced some of the best images of Earth of any satellite in recent years.

Proba stands for PRoject for On Board Autonomy. It was built to demonstrate a range of new technologies. The main instrument on board is the Compact High Resolution Imaging Spectrometer (CHRIS).

Funded by BNSC and built in the UK, the CHRIS imager has found a wide variety of uses from mapping ancient Roman remains to monitoring pollution in Hong Kong. There are currently more than 80 scientists using this data.

The spacecraft has also been deployed in combination with other satellites to help provide emergency relief following natural disasters (see also DMC). Proba’s continued success means that a successor, Proba-2, will be launched in the next few years.

Mission facts

  • Proba was the first ever microsatellite launched by ESA. The size of a large TV set, it weighs in at just 94 kg.
  • One of Proba's most recent successes came late in 2005, when it was used by teams in the Sahara looking at how to make the best use of a water supply buried deep underneath the desert. This ‘fossil water’ came from the Ice Age 10,000 years ago. It has been used to support population growth.


Proba has successfully tested a range of new technologies as well as providing some fantastic images of Earth.

The CHRIS instrument is the highest resolution imager of its type currently operating in space.

The spacecraft also carries two other cameras and a range of other instruments. Full details are are available on ESA's Proba web pages.

UK involvement

Although the Belgian company Verhaert led the design and development of Proba, there was considerable input from UK companies:

Surrey Satellite Technology Limited (SSTL) provided a Global Positioning Satellite (GPS) receiver for the satellite that can determine the latitude and longitude of a point on Earth.

Sira Space (now part of SSTL) built the Compact High Resolution Imaging Spectrometer (CHRIS), one of the two instruments on board.

For more information about Proba, visit the ESA website.

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