Christine Leurquin
SES ASTRA,
55 Avenue Tervuren
Brussels
Belgium
1040
European Space Agency
European Space Agency
Sat@Once is an Internet project, involving SES ASTRA in Luxemburg and CSP in Torino, Italy. Sat@Once uses the "Casablanca" technology to extend the Web in another dimension, while remaining fully compliant with all aspects of the "netiquette". After installing a free-download "Casablanca" client (7.1 MB), anybody equipped with a DVB-satellite-connected PC can listen to the transmission and capture a preview of the most popular web sites. The most popular homepages are chosen semi-automatically from the Internet, based on "votes" made by the total audience of users. The purpose of Casablanca is to select from all the static Web contents available for free on the Internet, the pages that are of interest to the maximum number of users and to broadcast these pages via satellite.
You may consider the usage of Casablanca as follows: the ASTRA satellites "soak" the ether continuously with previews of the most popular pages of the Web. Your free, personal and private copy of "Casablanca" client on your PC selects from this permanent biosphere the pages that are closest to your own taste. You preview the pages offline at your convenience, and decide which Web sites to read further. For the latter, and only for them, you need to connect. You may also use Casablanca to preview pages while connected; in such cases, only missed links are fetched from the Internet. The rest is served without delay from your Casablanca local storage.
Having popular web pages available for satellite preview has the following advantages for you as a user:
The key issues in the project is the number of receivers over Europe who will join the free-of-charge service, to take the maximum advantage of the satellite multicast capabilities, of the low cost DVB data receiver equipments, to extend the Web in another dimension to transmit the most popular contents to the maximum of people, either public, in local community or in a corporate community.
The main benefit of the project is to prove that multicasting popular web sites to the maximum of persons under the ASTRA satellite footprint is a service that brings broadband multimedia to the users with the minimum of cost. The power of the media can then be extended to piggy-back more community-oriented contents at a very low cost.
The System Architecture uses the Casablanca technology already developed and used by SES ASTRA customers in other contexts, worldwide.
On the server side, the votes from the user are received, aggregated to protect privacy, evaluated and the most popular web sites are automatically prefetched. The prefetched contents are indexed, profiled and announced before transmission.
The client receiver listens to the announcement, decides what to keep in the local storage. When the user wants to surf the web, if a page is already in the local storage, it is served immediately. In addition to popular web sites, special contents made for community uses can also to stored, pushed and captured on the user side.
To collect and bring content from the local content producers to the platform, we use terrestrial lines or BBI, the two-way satellite Ka-band system from SES ASTRA.
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The project plan is as follows:
The public distribution of the free software to receive the Sat@Once service started in April 2002 on an European scale. In February 2004, the audience is more than 86,000 registered users. Due to the popular success, Sat@Once is now transmitting more than 200 different contents simultaneously in one parallel channel dedicated to Italian contents, one parallel channel dedicated to German contents and a third parallel channel for the rest of Europe (French, English, Polish, Czech, Spanish).
