Olympus Satellite

Satellite

Olympus was built by British Aerospace for ESA (European Space Agency), and it cost about $850 million. At the time of launch, it was the largest civilian telecomms satellite ever built (2.9 x 2.7 x 5.6m). The satellite was launched on 12th July 1989 on Ariane flight V32 from Kourou, French Guiana. It was the first European satellite to offer capacity in the Ka band - (20 / 30 GHz) - a band which will become increasingly important over the next few years for internet communications by satellite. It also provided an innovative on-board processing, spot beams, and other experimental payload. The satellite was designed for an operating life of 7 years, but sadly never made this.

Olympus -1 was a satellite which has to be one of the unluckiest ever to reach orbit. In its short life, it suffered a solar panel failure, had an unscheduled trip round the world, and was subsequently used in an inclined orbit (Aberdeen University used specially adapted satellite terminals during this period) 1992-1993, It was finally damaged by an impact during the 1993 August Perseid meteor shower, and started spinning, finally to be decommissioned when fuel ran low !

The satellite used 3-axis stabilisation and had an orbital position of 18.8 W. It had two 27.5 m solar arrays which were designed to give a minimum of 3.6 kW at end of life. The communications payload comprised a two channel high power direct broadcasting payload operation at 12/18 GHz. Another was a four channel 12/14 GHz specialized services payload and a 12/20/30 GHz beacon package for propagation experiments. The last one was the 20/30 GHz payload for advanced communication experiments.

Projects

Analysis and Optimisation of CODE Protocols (ESA, 1992)

Use of X.25 Protocols on a 20/30GHz VSAT Network (BNSC, 1990)

Tele-Education

Cooperative Data Experiment (CODE)

As part of the CODE programme, Aberdeen University operated two 0.8m Ka-Band VSATs manufactured by NEWTEC CY under contract to ESA. It investigated the performance of TCP/IP over a VSAT LAN-interconnection system. A detailed analysis of the performance of the TCP/IP protocols was conducted, including well known application protocols such as RPC, NFS, X-windows, ftp and telnet. It has shown that most of these protocols provide performance comparable to that observed on most European terrestrial connections operating at similar speeds.

During 1992/1993, Aberdeen operated two NEWTEC VSATs allowing communication between the computers located on either of the LANs connected to each terminal, and also to the computers at the Hub Station at ESTEC (Noordwijk, NL). A mixture of PCs, Macintoshes and SUN workstations were interconnected, all using the TCP/IP suite of protocols.

A considerable amount of operational experience was gained using the CODE network with the Olympus satellite. Experiments were conducted to verify the simulations and observe the performance under operational conditions. Routine operations file editing, remote login, file transfer (word processor files, data, Postscript output, programs), reading electronic mail, etc were frequently performed over the CODE network. The experience gained provided valuable insight into the behaviour of the protocols. It has also indicated the need for a network management system and suggested the operational parameters which should be observed by the monitoring system.

A number of demonstrations were also organised connecting participants at ESTEC with participants at Aberdeen. The two groups exchanged data files, and were able to login to the various computers. The groups communicated using packet voice, carried as one of the TCP/IP services and used a video frame grabber to send still pictures of the equipment and participants to each other.

Research work at Aberdeen built on the experience of using the CODE system with Olympus, and supported work to commercialise CODE and benchmark the CODE IWUs (the USI and HSC).

Further Information

The OLYMPUS satellite programme

CODE-a Ka band VSAT system