Proba, The Washing-Machine-Like Satellite

By Roland Piquepaille

Proba, short for Project for Onboard Autonomy, doesn't look like an ordinary satellite. Launched in 2001 by the European Space Agency (ESA), it has the shape and the size of a washing machine. Located 600 km above our heads, it gathers 14-km square images of the Earth's surface at a resolution of 18 meters with its main instrument, the Compact High Resolution Imaging Spectrometer (CHRIS). And this is a very polyvalent satellite, used for agricultural mapping, water quality monitoring, charting forest fire damage and disaster management.

Here is an artist's rendering of Proba in orbit (Credit: ESA). Doesn't it look like a washing machine?

When ESA launched Proba, it was intended as a demonstration for several experimental technologies. But it worked so well that ESA decided to open the usage of CHRIS to scientists around the world. About 40 of these groups gatherd for a workshop last week in Italy to discuss their plans. Here are some of these neat projects.

• Inspecting trees in Belgium

  CHRIS's ability to retrieve hyperspectral and multi-angular data makes it especially useful for the study of vegetation cover on land. Francois Kayitakire of the University of Louvain's Water and Forest Unit in Belgium recounted research being carried out on the 10,000-hectare Nismes forest.

• Looking at cotton crops in Australia

  Ray Merton of the School of Biological, Earth and Environmental Sciences of the University of New South Wales in Australia explained how his team used CHRIS imagery as part of an investigation of how the reflectance properties of cotton might be used on an operational basis to estimate the crop's health, maturity and yield.

• Studying phytoplankton in Spain

  Ramon Pena-Martinez of the Centre for Hydrographic Studies of Spain's Centro de Estudios y Experimentación de Obras Públicas (CEDEX) explained how he was preparing to use CHRIS data in support of a project employing the Medium Resolution Imaging Spectrometer (MERIS) instrument on ESA's Envisat spacecraft to detect traces of potentially harmful phytoplankton in his country's reservoirs.

• Assessing the damages of large forest fires in Europe

  CHRIS is also set to join forces with another mini-satellite to survey the longer-term damage done by forest fires. When Proba was launched it shared its rocket with the Bi-Spectral Infrared Detection (BIRD) spacecraft designed by the German Aerospace Centre (DLR) to detect high-energy and fire events across the Earth's surface. Areas under target include last year's fire zones in Spain and Portugal as well Australia and Siberia.

• Checking the effects of natural disasters

  The Workshop also heard how the international Charter on Space and Major Disasters was considering an increase in its use of CHRIS imagery for high-resolution damage assessment as a response tool during disaster situations. Back in December 2003 a CHRIS image of flooding in the town of Ville d'Arles in France was acquired following a Charter activation.

Proba will be followed by Proba-2 next year.

Source: European Space Agency news release, May 4, 2004