Site: ESTEC, European Space Technology Center of the European Space Agency (ESA)
Keplerlaan 1
NL-2201 AZ Noordwijk ZH
The Netherlands

Date Visited: September 8, 1997

WTEC: C. Mahle (report author), K. Bhasin, C. Bostian, W. Brandon, R. DePaula, N. Helm, A. Mac Rae, J. Pelton, S. Townes



Mr. Ashford reviewed ESTEC's history, charter and current status. As described in the previous WTEC report (1993), ESA has "mandatory" and "optional" programs. Scientific satellites are still a "mandatory" part of the "basic" program. Application satellites (in particular telecommunications satellites and applications) are "optional," i.e., the member countries do not have to contribute and participate. Mandatory programs must be funded by member nations according to a percentage of GNP; optional programs (for instance the Telecom program) need participation by two or more countries on a voluntary basis to get started. Funding from member countries pays for ESA's operations (about 15 to 17% of the total funding) and the rest is plowed back to industry. Typically a country will receive at least 90% of the share it paid in (after ESA's operations costs are subtracted), provided industry in that country can perform the required work. In the last five years ESTEC experienced a time of tight budgets which resulted in a realignment of some programs and a streamlining of the organization resulting in a merger of some management layers.

The telecom program is making a strong comeback; industry and governments in member countries like to see work in Europe to counterbalance funding by the U.S. military and the Japanese government in support of commercial satellite communications.

ESA funds programs in MAU (millions of accounting units, currently one ECU is equivalent to about $1.20). ESA's telecom funding is about 250 to 300 MAU (i.e., approximately $300 to $360 million) per year for specific telecommunications space and ground systems. In addition, generic technology applicable to telecommunications (for instance spacecraft batteries) is funded at about 40 to 50 million MAU per year (about 25 million via TRP, and 10 million via GSTP). The total funding applicable to telecommunications is therefore about 300 MAU per year. It should be understood that individual members have in some cases substantial national programs in addition to ESA's telecommunications work.

ESTEC has recently developed a remarkable flexibility in working with member states and industry to accomplish work in the telecommunications sector in a timely manner. This shows in the ARTES program where several different mechanisms of funding and program management are apparent leaving the impression that ESTEC uses substantial administrative imagination to get work off the ground and keep it running.


Olympus was the last major satellite developed by ESTEC. Olympus was launched in 1989 and operated successfully for several years despite a near loss of the spacecraft. The Olympus payload technology as well as the results from many of its experiments were very valuable and have since been used in the industry.

Except for ARTEMIS and DRS, no new telecommunications satellites are planned in the future; ESA will only fund non-recurring expenses (NRE) for new technology and applications/new service demonstrations, that can later be turned over to industry. ESA's work in telecommunications satellites and applications is performed to help European industry to be competitive in the world market. Any technology spin-off from ESA's programs is for the benefit of industry. ESA will not develop a new telecommunications satellite unless industry desires it and also funds at least a part of it. The operation of such a satellite would later be turned over to an operating entity.

In addition, Mr. Ashford listed briefly programs by the European Commission (EC), and some national space agencies and commercial operators as far as they are applicable to the telecommunications satellite sector.

Highlights of Europe's current telecommunications work can grouped into a number of programs, many with ESTEC involvement:

DRTM Program

ARTEMIS (Advanced Relay and Technology Mission) is a satellite for the development, demonstration and operation of data relay services operating at S-band, Ka-band, and optical frequencies. An L-band payload complements the European Mobile Satellite (EMS) payload on ITALSAT F2. A navigation payload is currently being added. Launch was originally scheduled on the Ariane 5 APEX flight, but will now be launched on an H2A rocket in 2000. The financial envelope for the program is 800 MAU.

ARTEMIS is currently under construction at Alenia as prime contractor. The S-band link will collect data from several LEO satellites and transmit it to a ground station. Three L-band spot beams cover Europe; a single beam similar to EMS can be generated. The optical payload (SILEX) will communicate with a similar payload on the SPOT 4 satellite. A defined common optical interface allows it to also work with the Japanese OICETS satellite. The satellite uses ion propulsion (xenon thrusters) for station keeping manufactured by MMS and DASA. The thermal/structural model has completed testing, a PFM is currently being integrated and the ground segment is under development. An optical link simulation with the Japanese OICETS satellite has taken place. The ground segment includes an optical station on the Canary Islands (already in operation).

The DRS (data relay satellite) program envisages the development and operation of data relay satellites and ground infrastructure operating at S-band, Ka-band and optical frequencies with LEO to GEO links. The program was reduced to one satellite as ARTEMIS can provide the functions of the second planned satellite. Phase 1 (proof of concept) has been completed; the program continues at low level until full funding is decided upon by the JCB (Joint Communications Board) for the 1998 - 2001 time frame.

ARTES Program

ARTES is an optional program and functions as an umbrella; 14 countries are currently participating. ARTES has currently 12 elements, not all are fully funded. As it is an approved umbrella program, individual elements can be started with relatively little administrative work.

A list of the 12 elements and their funding is presented in Table B.2.

Table B. 2
Artes Programme Elements



Financial Envelope (MAU)


Preliminary studies & investigations



Onboard processing Step-1



Multimedia & high data rate systems



Telecom partnership programme

23.6 + 23.6


Advanced systems and telecom equipment

62.6 + 26.9


Advanced mobile systems



Experiments & demonstrations



Multi-orbit small satellites



Guidance & navigation satellite system- I



Guidance & navigation satellite system- II






Little LEO messaging service


The status of these elements was described as follows:

Element 1

Is funded until 1999 by all members according to the percentage of their GNP. (France and Italy are expected to join soon.)

Element 2

Work on a laboratory model onboard processor (OBP) is almost complete; hardware testing is ongoing.

Element 3

Has recently been opened for subscriptions to develop multimedia and high data rate applications in cooperation with the EC and national agencies. There are three main thrusts:

Element 4

Was started by industry in the U.K. and is ongoing through 1999. It is funded 50/50 by industry and ESA. ESTEC evaluated proposals and currently helps industry manage the program. Results should be applicable commercially in about two years.

Element 5

Two phases are ongoing in parallel to develop techniques and not technology.

Element 6

This is currently on hold. It was intended to investigate LEO systems and will probably be re-started in 1998.

Element 7

Has been completed, additional effort will continue under Element 5.

Element 8

Development of an advanced small satellite bus with 500-1,000 kg mass intended for GEO, MEO and/or HEO applications. It is currently on hold until a particular mission is identified.

Elements 9 & 10

These deal with a satellite navigation program. The primary application is air traffic control and navigation. The program is carried out jointly with Eurocontrol and the EC. The program will initially use GPS and GLONASS satellites. Element 9 is the EGNOS program to provide integrity information (supplementing GPS and GLONASS) via L-band packages on 2 or 3 GEO satellites.

In the future, Element 10 (GNSS 2) is foreseen to proceed towards a full civil system, as a military controlled navigation system is not acceptable to civil aviation.

Element 11

Archimedes (Advanced Research High Inclined Orbit Satellite): paper study of a satellite for radio broadcasting in HEO, awaits decision by industry.

Element 12

Addresses little LEO messaging with two small satellites; Belgium and Germany participating; launch was in late 1997 on a Russian rocket as secondary payload.

Onboard Processing

Details were presented on onboard processing and on the history and current status of optical intersatellite link (ISL) work.

A laboratory model onboard processor has been developed under Element 2 of ARTES since 1994. Systems engineering, concept validation and testing have been completed and processor prototype development is ongoing.

The processor application is for a GEO satellite with many spot beams in Ka-band; the user uplink data rates range from 512 to 2,048 kbps with multifrequency TDMA access. The downlink to the user is a 32 Mbps TDM stream. The processor architecture is laid out in multiples (N) of 262 Mbps. Total user population would be 150,000 * N for 512 kbits and 1000 * N for 2,048 kbps per user. User interfaces are ISDN (circuit switched) and TCP/IP (packet switched); both schemes are switched/processed onboard the satellite in a user transparent manner.

The onboard hardware requires the following items still to be developed:

The system will be able to handle videoconferencing with many users.

Partners in the development are Alenia, Alcatel Madrid and Intraspazio Barcelona. Major subcontractors are Bosch Telecom, Siemens Austria, Spar, IMT (Canada), Alcatel Belgium and Laben Italy.

Optical ISL Work

Optical work for ISLs started 1985 with a systems study using CO2 lasers with data rates from 500 to 1,600 Mbps for LEO to GEO and GEO to GEO applications. A breadboard was built with a homodyne receiver and a 10 W laser supporting a data rate of 1 Gbps bidirectionally. The program was completed in 1988.

The SILEX (Semiconductor Intersatellite Link Experiment) program started in 1986 using semiconductor lasers for LEO to GEO applications with 50 Mbps and a GEO to LEO link with 2 Mbps. Later it was recognized that the 2 Mbps return link was not essential. Laser diode power at the time was about 100 mW at 800 nm (laser diodes by SDL, U.S.). Triple redundancy for the laser diodes is provided. Direct detection is used with a sensitivity of 40 photons/bit (detector by EGG, Canada). A 25 cm dia. telescope has 3 detectors, one for the data, a CCD detector for acquisition and a CCD detector for tracking. Temperature stabilization is performed to 0.5C. Coarse pointing is performed via motors that move the main telescope mirror, look-ahead fine pointing is accomplished with piezoelectric actuators moving a fine-steering mirror. The two flight models are completed; the LEO model was delivered to the SPOT 4 satellite, the GEO model to the ARTEMIS satellite at Alenia. ESA spent approximately 120 million MAU for SILEX and Matra added some internal funding.

The SOUT (small optical user terminal) program is a cooperation with Matra Marconi Space (MMS) started in 1991 and completed in 1995. This ISL terminal would be mounted in a LEO satellite of a user and transmit data to a GEO satellite. It is based on SILEX technology and a breadboard demonstration unit was built. For a flight model the mass would be 25 kg and the power 40 W. A 7 cm diameter refractive telescope is used with a crosspointer mounting attachment close to the center of gravity. The laser is fiber coupled; point ahead tracking is implemented. The size of the optical bench is 25 cm and the data rate is 2 Mbps. With a different laser driver 50 to 100 Mbps can be achieved.

The SOTT (small optical telecom terminal) program started in 1995 and is also a cooperation with MMS. It addresses high data rates for GEO to GEO ISLs. The laser diode assembly has 2 W output at 800 nm, the data rate is 1 Gbps and a 20 cm diameter telescope is used. So far a paper study has been completed. Overall mass and power are 50 kg and 100 W. The program is continuing as SOTT II at MMS for a LEO to LEO ISL and will continue until 1998.

The SROIL (short range optical intersatellite link) program, started in 1996 and funded by ARTES (Element 5), is developing a miniaturized terminal at Contraves (Switzerland) for LEO to LEO ISLs. It uses a Nd:YAG laser, homodyne detection using "sync bit" technology (a DLR patent) with a PLL and piezoelectric tuning of the laser resonator. DLR achieved 4.5 photons/bit sensitivity in such a demodulator at 2 Mbps rate. The data rate of SROIL is 1.2 Gbps, the overall mass and power for a flight model 15 kg and 40 W. Size is approximately 30 x 20 x 50 cm with a 4 cm dia. telescope. A breadboard demonstrator is to be completed in 1998.

SOLACOSS (solid state laser communication system) was developed by Dornier under German national funding between 1991 and 1997. It uses a Nd:YAG laser; data rate is 650 Mbps and overall mass approximately 75 kg. No follow-on work is currently planned.

The evolution of the optical technology for satellites over time is shown below:

Telescope dia. (cm) 25 15 7 20 4
Mass (kg) 160 75 25 50 15
Power (W)   75 40 100 40


European Land Mobile Service

As part of its activities in support of the initiation of a regional European satellite land mobile communications system, ESA has leased capacity on Marecs and EMS to Nuova Telespazio (NTZ) to assess the market for land mobile service at L-band. EMS is an L-band payload (60 kg, 400 W, EIRP > 42 dBW, G/T > - 2 dBK, covering Europe) on ITALSAT F2, launched in 1996.

GAMMA Project

GAMMA (global architecture for multimedia access) aims to connect many users all over the world to many servers via a high speed ring and invite user communities to develop applications. Currently, high data rate experiments with Japan (MPT/CRL/Kansai, PII/NASDA/Keio University) are conducted via an INTELSAT IOR satellite. The link has 2 to 6 Mbits data rate for multimedia experiments. In the near future, this link will be established via a Ku-band satellite with the data rate eventually increasing to 45 Mbps and later to 155 Mbps. ESTEC has the modems (a Belgium company developed them) and knows what to do with 155 Mbits data rate. This is funded 50/50 by industry. Core members are: Swiss Telecom, Newtec (Belgium), and NTZ. Applications so far are: telemedicine/tele-education, Virtual Museum (NTZ), ISIS (Alenia), ISIS-TM (Matra CAP) and video conference (France Telecom).

SHARED Project

SHARED is a telemedicine project initiated by an Italian user group including hospitals and the military. The project has connected three hospitals (Milano, Roma and Sarajevo) since 1996 via a DICE multipoint videoconferencing system and a EUTELSAT satellite. Recently, two hospitals were added to the system.


SKYPLEX is an on-board processor developed by Alenia for a digital TV system that uses technology from ESTEC's OBP work; it allows the combination of several digital TV uplinks in the satellite onboard processor to form a DVB/MPEG type downlink. This equipment will fly on EUTELSAT Hotbird 4 in late 1997. Participants are: ESA, EUTELSAT, Alenia, Alcatel Espace, MMS.


The EC is funding the ACTS (Advanced Communications Technology & Services) Program.

DIGISAT (Advanced digital satellite broadcasting & interactive services) and ISIS (Interactive satellite multimedia information system) are EC programs with ESA involvement.

DIGISAT uses Hispasat at Ku-band for trials to provide small communities with an interactive multimedia system. The return link uses secure CDMA technology. Participants are the EU (ACTS), ESA, Hispasat, Philips, SAGEM, FUBA, RAI, Retevision, RTE, and Antenna 3.

ISIS is coordinated by Alenia to demonstrate direct-to-home interactivity. The program addresses a low cost user terminal for DVB reception, which includes a Ka-band return link capability. Current satellites have no capability for a Ku-band return link. The project will use TCP/IP embedded in the DVB data stream (about 30 Mbps); the return link is via frequency division multiple access (about 2 Mbps) and needs on the order of 2 W rf power at the Ka-band user terminal. ESTEC engineers believe that the cost of the Ka-band station scales with frequency; it is not expected to be significantly higher than Ku-band equipment. Current experiments use EUTELSAT Hot-bird and ITALSAT, which are collocated. Participants are the EU (ACTS), ESA, EUTELSAT, Alenia, Philips, IBM Semea, RAI, NTZ, Space Engineering, MAC, Univ. of Salzburg, Univ. of Florence, CUM, INTRACOM, and Balkan Press.


The ARTE (Alternative Distribution Strategies for Real Time European Data) project is to investigate opportunities for broadband communications via satellite in Europe. Currently, pilot projects are under way to transmit earth observation image data at ESRIN to users. Today's mechanism is shipment of CD-ROMs, which takes weeks. Initially, a EUTELSAT satellite will be used to demonstrate the concept. The return link will be via the Internet. In the fall of 1997, image data transmission via a broadcast satellite system (DVB/MPEG) will start to demonstrate the benefits of the method. In the future, the return link will be at Ka-band from the user to satellite (ITALSAT, collocated with a EUTELSAT satellite); as this link needs little capacity, when errors occur, a retransmission of the lost packet occurs. In this way a Ka-band link with small margin is feasible.

Currently ASTRA and EUTELSAT have data broadcast (DVB) commercially available via their satellites. Astra 1H (to be launched in the next year) will be able to do interactive data broadcast with a Ku-band forward link and a Ka-band return link.

CNES has been working on the STENTOR program since 1993. The program is developing a 2000 kg satellite intended for GEO with 2,400 W in daylight and 1,800 W during eclipse. Three payloads are onboard: an L-band aeronautical payload, a Ku-band multipurpose payload, and a propagation experiment at 20 and 44.4 GHz.

Alcatel is working on SATIVoD, a 32/64 LEO satellite system at Ku/Ka-band with uplink data rates of 16 kbps to 2 Mbps and downlink data rates of 16 kbps to 60 Mbps.

Alenia is working on Euroskyway, a GEO system with 4 satellites and with uplink data rates of 16 kbps to 2 Mbps and downlink data rates of 32.8 Mbps to users in Europe. Onboard processing and ISLs (622 Mbps, optical) are used.

MMS is working on WEST; 1 to 2 satellites at GEO and less than 10 at MEO; uplink data rates of 32 kbits to 10 Mbps & 155 Mbps and downlink data rates of 10 Mbps & 155 Mbps.

MPT (Japan) and ESA are planning a Gigabit satellite at GEO with uplink data rates of 2 to 8 Mbps and downlink data rates of 60 Mbps. Two satellites would be connected with a 1 to 2 Gbps optical ISL.


ESTEC has added several capabilities to its facility since the 1992 WTEC visit. Two multipactor evaluation facilities ranging from 1 to 30 GHz with power levels up to several kW are located in the microwave lab.

The environmental testing area has two major new facilities, a 3-axis hydraulic shaker for very large satellites and a large acoustic chamber capable of handling ENVISAT (an environmental satellite over 10 m long with a large radar antenna).


Europe has now at least three commercial operators: EUTELSAT, ASTRA and Hispasat.


In the last decade the telecommunications program at ESTEC has changed emphasis from large satellites (Olympus, ARTEMIS) to a multiplicity of smaller programs in conjunction with industry, which uses satellite technology (developed by ESA programs) and demonstrates new services.

Published: December 1998; WTEC Hyper-Librarian