Site: Alenia Aerospazio, Div. Spazio
Via Saccomuro, 24
00131 Rome, Italy

Date Visited: September 12, 1997

WTEC: C. Bostian (report author), K. Bhasin, C. Mahle, A. Mac Rae, R. DePaula, S. Townes

Hosts:

BACKGROUND

Alenia Spazio is one of the world's leading space communications companies. It is at present a division of the Finmeccanica Company, and employs approximately 2,500 people in 7 locations. It was the prime contractor for a number of telecommunications and scientific satellites, and its products are part of more than 100 spacecraft. Alenia's commercial sales were (or are projected to be) about 87 billion lire in 1995, 255 in 1996, 340 in 1997, and 442 in 1998. Its government sales were 693 billion lire in 1995, 595 in 1996, 670 in 1997, and 738 in 1998. Corporate strategy calls for keeping the government work at a constant level and continuing to increase the commercial business. R&D expenditures are approximately 20% of sales.

RESEARCH AND DEVELOPMENT

Alenia specializes in telecommunications, remote sensing, scientific satellites and other space hardware and services. It pioneered Ka-band spacecraft with onboard processing, being involved in both since the 1980s. From the 1970s until 1985 it primarily built payloads, and since then it has also built satellites. Its operating mode has changed from one in which its customers brought it technical specifications to one in which they specify services. In the latter case Alenia does the systems engineering and may design an entire network, including both the space and ground segments.

Systems Engineering

Alenia works on all aspects of satellite systems engineering, including:

Multimedia Satellites and Onboard Processing

According to Alenia, the key issues in designing a multimedia satellite system include:

Alenia's operational experience goes back to 1991, when ITALSAT F1, operating at Ka-band, was launched with a regenerative processor onboard. The spacecraft covered Italy with 6 spot beams. Incoming signals were demodulated and switched at baseband, with outgoing bits routed to the appropriate downlink spot beam and remodulated. It used a TDMA system operating with a throughput of 147 Mbps, supporting 12,000 32 kbps channels. Alenia sees the task now as one of developing systems like this for small users. ITALSAT F2, carrying a mobile ESA payload, was launched in 1997.

The SECOMS/ABATE projects (September 1995 - August 1998) have as the following objectives:

The proposed network architecture is a Ka-band satellite with 524.3 Mbps links to terrestrial gateways and 131.1 Mbps or 32.768 Mbps intersatellite links. It will connect to fixed user terminals and the PSTN at multiples of 32.768 Mbps. Vehicular terminals will connect at rates between 160 kbps and 2.048 Mbps.

The ISIS/MMIS projects (October 1995 - December 1998) have as their objectives demonstrating an all-via-satellite interactive multimedia system with Ka-band uplinks and Ku-band downlinks to subscribers. Forward protocols will be IP over MPEG-2 and DVB. Return links for ISIS will be IP transmitted by DQPSK SCPC at rates up to 64 kbps. Return links for IMMIS will be IP transmitted by QPSK over multi-frequency TDMA at data rates up to 1.024 Mbps. User terminals will use 90 cm antennas and SSPA transmitters with power levels ranging from 0.5 to 2 W.

Euroskyway is an application program aimed at developing breadboard hardware for a European multimedia

satellite system at Ka-band with V-band (56/64 GHz) ISLs. The spacecraft will generate multiple high gain spot beams and operate with 9.2 Gbps gross capacity.

Skyplex is a program to develop an onboard regenerative multiplexer that will combine DVB programs for video broadcast. Currently digital TV programs coming from different sources have to be multiplexed at a single earth station and uplinked to a satellite. The planned systems will allow them to be uplinked independently and combined at the satellite for retransmission to users on the ground. Flight models were expected to be delivered before the end of 1997.

In response to later questions about the future of mobile communications, WTEC's hosts said that Alenia is "playing the mobile multimedia card." This is apparently where they think mobile satellite markets will develop.

HALE Platforms

Skystation is a concept for a 150 m long balloon to provide terrestrial multimedia service from a platform approximately 23 km above the earth's surface. It will support 110,560 total simultaneous users. Of these, approximately 75,040 will be in the so-called urban area coverage (UAC) directly under the balloon and operate with 100 mw, 23 dBi gain terminals that can be user installed. The remaining 35,520 users will be in the suburban area coverage (SAC), operating with 150 mW, 38 dBi gain terminals that require professional installation. The system will support up to 15 gateway terminals which may be anywhere in the SAC and UAC. While Skystation is not a space project, it uses much of the same technology as a communications satellite system, and it would compete with planned Ka-band multimedia satellites.

Satellite Manufacturing

Alenia is in the forefront of the global transformation of satellite building from a long-lead-time one-at-a-time operation into assembly line production. This is evident both in the Globalstar integration work (discussed below) and in the company's turnkey production of the NAHUEL Ka-band satellite for Argentina in 18 months from design through integration and systems testing. Other turnkey jobs include CESASAT, being made for a Czech company.

Alenia's Globalstar integration and test facility is a state-of-the-art complex for producing four spacecraft per month. It organizes the work into a series of "islands" where the major tasks are completed. The process was carefully designed with great stress on both efficiency and quality. When the Globalstar run is finished, Alenia plans to use the facility and its acquired knowledge to manufacture other families of small satellites. One example of programs where this might be done is COSMOS, a European program that envisions a constellation of small remote sensing spacecraft.

Antennas

Alenia has long enjoyed a well-deserved reputation for excellence in antenna design and manufacturing. It supplies a variety of products to all the major satellite contractors. New systems include Ku-band systems with elliptical or otherwise shaped beams that can be rotated on command, a new feature added to a number of reconfigurability options. Alenia is looking into incorporating smart materials into carbon fiber reflectors, but no hardware has been built.

Alenia's work in active phased arrays includes building the L-band antennas for Globalstar to Space System Loral's design. These are 60 element circular patch arrays. The basic array structure is hexagonal, organized into five 12 element triangular subarrays. It will probably be the first flat panel direct-radiating active phased array to be launched. With its impressive capabilities in rf and microwave electronics technology and its experience in building arrays for satellites, Alenia is clearly a leader in active phased array technology.

When questioned, WTEC's hosts said that they were currently not involved in using optical (photonic) technology in phased array antennas.

Electronic Components and Subsystems

Alenia builds a number of GaAs MMICs and HMICs for frequencies up to at least 34 GHz. These include LNAs, modulators, demodulators, channel amplifiers, etc. Prototype S-band transponders digitize the second IF. Alenia's efforts have been toward developing the important electronic building blocks and combining them in different ways to create different products. Alenia does the design work and has the commercial products made in the standard foundries. The company is looking at InP devices for operation at frequencies beyond the capabilities of GaAs.

CONCLUSIONS

Alenia Spazio is a world-class space systems and hardware company. It has added new capabilities and facilities since the 1992 WTEC visit, particularly in small satellite integration and testing.


Published: December 1998; WTEC Hyper-Librarian