A new dawn for satellite observation systems

Compared to Galileo, a single satellite system with a single operator and five primary products, the GMES (global monitoring for environment and security) programme looks much more complex.

This ‘system of systems’ will bring together a comprehensive set of earth observation sensors to acquire, process and deliver a wide range of data and derived products to a variety of public and private users. To implement this ambitious project, the EU and the European Space Agency (ESA) must avoid repeating the same mistakes that almost stalled the Galileo project and inventing new ones.

The progressive implementation of GMES will build on existing environmental and remote-sensing satellites, as well as on the introduction of a new series, the Sentinels, developed by ESA to ensure data continuity.

This is one of the major requirements of environmental remote sensing: the flow of data must never be interrupted. An overlap is thus needed between satellites. Most of the time, they do not get absolute measurements but relative ones and a new satellite has to be calibrated with its predecessor to ensure that its data will be coherent for feeding digital models. The US/French Topex-Poseidon and its Jason 1 follow-on monitored the height of waves to the level of centimetres. But when Jason 1 was first switched on, there was a two-metre gap between its readings and those of its predecessor. The overlap between the two enabled the science team to fine-tune the new satellite. Today Topex is gone, Jason 1 has exceeded its contractual lifetime and its successor is still more than one year off, with no contingency plan in case of launch failure. If the data flow stops, more than 15 years of oceanography data - a key element for GMES - will be rendered nearly worthless.

Envisat, the ESA’s largest satellite - carrying ten instruments to monitor the atmosphere, the oceans and landmasses - also exceeded its design life last March. It will not be replaced until the first Sentinels are launched, in at least five years’ time.

The initial budget for GMES is estimated at about €2.4 billion. ESA has issued requests for proposals to develop the first three Sentinels, through an initial €253 million envelope awarded by ESA’s member countries in December 2005. On the European Commission’s side, funds were obligated through the 6th and 7th research framework programmes for research (FP6 and FP7) to support development of the data acquisition and processing, as well as studies for ground system infrastructures and future recurrent operational satellites - a major issue because of the need for generational overlap.

FP7 includes €800m for space segment development and €400m to foster associate services. But under the current EU rules, the industry should provide matching funding. Perhaps unsurprisingly, it is reluctant to do so. "For such a programme, this is meaningless, as GMES is about infrastructure, not R&D," claims Joël Chenet from Thales Alenia Space.

A solution might come next year, with a new ‘infrastructure’ line in the R&D budget. France, which will hold the presidency of the EU in the second half of 2008, reportedly plans to initiate an advanced funding contribution by the Commission departments using space data (agriculture, transport and energy, environment, fisheries, regional policy) instead of the current retrospective payment policy, which gives poor results. A contribution pattern will have to be devised and discussed.

Such a move will face objections from opponents arguing that ‘free’ data are already available from other satellites and instruments worldwide. But such data are often not adapted to the needs of European users, nor coherent between different sources. Above all, they offer no guarantee of continuity. One of the key objectives of GMES will thus be to guarantee the relevance, continuation and coherence of data.

This will give European scientists an easy access to the best data available, so that they need not develop their algorithms on lower-quality data simply because that is what is freely available on the internet, which is what happened with the Meris spectrometer on Envisat, whose water quality, atmospheric and vegetation data are less used than that of NASA’s inferior Modis camera.

Following the near-fiasco of Galileo, a public-private partnership has been ruled out for GMES. A ‘data-buy policy’, where the industry develops and operates the satellites to sell data to the government, is not considered a good option either. NASA experienced this option with the SeaWIFS instrument onboard Orbimage’s SeaStar satellite before going back to more traditional scenarios to ensure the continuity of vital data.

To operate the overall GMES, the plan is now to select a ‘service operator’, rather than a concessionaire. But the idea is still to have it pay for the recurring satellites, to follow the first generation Sentinels provided by ESA.

The European Meteorological Satellite Organisation (Eumetsat) has been proposed to play that role, but the largely successful operator of the Meteosat and MetOp satellites is not that much interested, at least not in carrying the burden alone. Although it is already involved in climatology and oceanography beyond its traditional weather-watch mission and its satellites will play a key role in the early GMES, providing 70% of the data, Eumetsat is not a significant player in some strategic parts of the programme, like land survey or security. Nevertheless, the Eumetsat concept is now the benchmark and the challenge is to model the GMES operator on the same kind of successful intergovernment agency.

Compared to Galileo, a single satellite system with a single operator and five primary products, the GMES (global monitoring for environment and security) programme looks much more complex.