Internet ready for Mars image traffic

While scientists around the world salivate at the prospect of sampling soil contents and finding water on the red planet, corporate webmasters and network managers may be eyeing NASA's Mars Polar Lander mission from a more down-to-Earth perspective.

NASA and its contractors have built a heavy-duty Web site that's expected to take 250 million hits in the first three hours after Mars photos are beamed to it - far more traffic than e-commerce sites would ever see in such a short time span.

Cable and Wireless USA (C&W) is providing the Internet backbone and four regional server centres that will feed Lander photos from the Deep Space Network at the Jet Propulsion Laboratory in Pasadena, California, to the Internet.

The last Mars photos came from the Pathfinder mission in 1997. There were about 100 million hits for Pathfinder photos in the first few hours of availability, and experts have guessed that the audience will be two and a half times larger this time, sources said.

C&W said strategically placing server sites in the four major metropolitan areas - Reston, New York, Chicago and San Francisco - was intended to assure that there would be no single point of failure.

Moreover, by connecting these servers to its 10G bit/sec. backbone, C&W figured the plumbing was in place to handle all the traffic earthlings could muster.

But just in case everybody in one city decides to mouse-click at the same time, load-balancing technology from Seattle-based F5 Networks is being used to even out the Lander photo load across the four server centres.

For example, if heavy early-morning Web traffic in the Northeast were to overload the New York server, Web requests could be automatically diverted to San Francisco, where hit rates would be lower because of the time-zone difference.

File-Caching

To increase the availability of the most popular Polar Lander photo files, C&W also has placed file-caching devices from Network Appliance at each server centre.

The caching systems monitor repetitive requests from different users for the same information and store the appropriate data at the very edge of the network. That speeds access for users and frees up the primary servers to increase overall network performance.

The images will be available at www.MarsPolarLander.org and at http://MarsLander.jpl.nasa.gov.