Technologie France Number 13




The military optic observation satellite, Helios 1A, was built at the Matra Marconi Space facility in Toulouse. There the new satellite was shown to large official delegations led by the French, Spanish and German Ministers of Defense. The 2.5 ton satellite is the baby of the first European space defense program. Next summer at Kourou, Guyana an Ariane 4 rocket will launch the satellite into a sun-synchronous orbit. The orbital plane of the satellite will rotate by one degree per day just like the apparent movement of the sun. Helios 1A, the first European military observation satellite, can detect 1 m details from its 700 km altitude orbit. So it will be able to continuously and repeatedly generate detailed images of every point on the planet. The ground facilities of the system will therefore be able to provide priceless documents to civilian authorities and the military command.

During the eighties, it was decided to set up a space defense observation system commensurate with France's ambitions. The scheme was prompted by the lessons learnt from the Iran-Iraq war, from the Afghan conflict as well as by the need to be more fully apprised of the Warsaw pact countries' potential. When the Spot satellite was launched for the first time, it confirmed the value of satellite images and showed that they could be exploited for military purposes. So the first European space defense program, the Helios 1 program, was set into motion.

A top priority defense program

In the early nineties, the upheavals incurred by a new geo-strategical setup proved how important space reconnaissance was. This became even clearer with the Persian Gulf war when countries with satellite observation systems proved the supremacy of their intelligence systems. France was instrumental in furthering the cause by providing Spot satellite images. It became clear that an independent satellite observation system with performance-levels adapted to the prerequisites of modern defense systems was vital.

The Helios 1 program has been allocated a 14 billion FrF budget. Besides France, its development is promoted 14 and 7% by Italy and Spain, respectively. Since the Gulf War the Helios 1 program has been given top priority in the 1994 White Paper on defense. According the 1995-2000 five-year schedule, 4% of the Defense Ministry's equipment costs will go to the space industry, i.e. 4 billion FrF per year compared to 1 billion francs in 1987.

Helios 1A and 1B for now, Helios 2 for the year 2000

Construction on Helios 1A began in February 1993. Next May or June, an Ariane 4 rocket is slated to launch Helios 1 into a sun-synchronous orbit at a 800 km altitude. The satellite will only become operational three months later. Meanwhile construction began on a second Helios satellite, Helios 1B, in February 1994, and is slated to be finished by the close of 1996. Helios 1B could be used as an emergency satellite in case Helios 1A breaks down. Helios 1A is slated to last four to five years. In other words, if everything goes as planned, Helios 1A should be functional until the year 2000 or even 2001 in order to link up with Helios 2A. In April 1994, Francois Leotard, the Minister of Defense, made the decision to start work on defining Helios 2A.

1500 engineers worked on the Helios 1 program, headed by the DGA1 and project engineered by the CNES2. To be successfully carried out in the current economic environment, the program has sought to improve gains made by existing programs and exploit the common ventures and dualities between civilian and military programs.

Helios 1 made profitable use of the civilian Spot satellite program. Indeed Helios 1 is a derived product with much higher performance-levels. Thanks to this approach, one billion francs were saved by eliminating the need for preliminary studies. The general architecture of the two systems is extremely similar. Helios 1 and Spot will be using the same platform (taking care of piloting, power supply and propulsion) and the same magnetic recorders which can store several hundred images. Both satellites will be controlled from orbitographic station-keeping centers with a shared core.

A highly efficient optical instrument

The Helios system includes an orbiting satellite and ground facilities. Helios, a state-of-the-art technological gem, is a remarkable, highly efficient image-shooting tool built by Aerospatiale. Its swivel system can record observations at an oblique angle and its star sensor can fine-tune space positioning. The image-shooting tool, considered as the most efficient built-in optical instrument ever made in Europe, means Helios can detect one meter details from its 700 km high orbit. The American Landsat satellite only has an 80 m resolution while Spot 4 offers a 10 m resolution.

The swivel system which can be programmed at will uses momentum wheels so the satellite can aim at areas located some 400 km from the area it is flying over. Helios also can cross-image by just rotating one mirror. With its swivel system and mirror rotation, Helios is more readily available for operations.

All the satellites belonging to the Spot family have infra-red sensors which can detect the planet's heat and indicate the satellite's position in relation to the earth at all times. Unfortunately weather variations cause the planet's heat to fluctuate, so measurement accuracy never exceeds 3 to 5 hundredths of a degree. So Helios was equipped with star sensors, somewhat like video cameras that can detect reference stars. A prototype of the system has proved trustworthy on the Russian Granat satellite and should be installed on a new satellite called Envisat.

European military space is slowly getting organized

The ground facilities used by the armies of the three countries are organized around the CPHF3 located near Paris. Besides image requests from the French authorities, the CPHF also receives requests from the CPHI4 near Rome and from the CPHE5 near Madrid. The CPHF also draws up daily satellite programs that it then transmits to the Orbitograhpical Station-Keeping Center (CMP6) every day so that the work schedule can be loaded onto Helios. The CMP has been set up at the CNES grounds in Toulouse where it controls the satellite with remote controlled stations located at Aussaguel near Toulouse, at Kourou in Guyana and on the Kerguelen islands.

Once the work schedule has been completed, the images are recorded on board the satellite and transmitted during each passage over the image receiving centers located near Colmar (France), Lecce (Italy) and Maspalomas (Spain). The different Helios centers in each country then receive the data they will proceed to exploit.

European military space seems to be slowly organizing around this new family of satellites. Engineers are already working on the design of a Helios 2 with greater image resolution and an increased image-shooting capacity. Helios 2 will also be equipped with a new instrument which can record findings at night and detect activity at the sites under observation.

Contact - Matra Marconi Space - Tel. Fax.

DGA, Delegation Generale pour l'Armement, general weapons division.

CNES, Centre National d'Etudes Spatiales, national space research institute.

CPHF, Centre Principal Helios Francais, main French Helios center.

CPHI, Centre Principal Helios Italien, main Italian Helios center.

CPHE, Centre Principal Helios Espagnol, main Spanish Helios center.

CMP Centre de Maintien a Poste.