Ethernet LANs have been used everywhere from the data center to the home and even the Starbucks around the corner. But space could very well be the final frontier for the technology.
On the Columbus module in the Atlantis Space Shuttle that rendezvoused on Feb. 16 with the International Space Station, the European Aeronautic Defense and Space Company installed customized ProCurve 100M bps LAN switches designed to connect not only computers on the ISS, but also scientific test and measurement equipment.
The Columbus, which docked with the ISS to become another component of the ISS, is the first European lab dedicated to long-term space research and is Europe's largest contribution to the buildout of the ISS.
The Columbus carries a series of five racks, or payloads, that each perform specific functions. The Biolab payload, for example, allows researchers to conduct experiments on micro organisms, cell and tissue cultures and small plants and animals. A Fluid Science Lab payload looks at the complex behaviors of fluids and a European Physiology Modules facility payload is intended to allow long-term study on the effects of weightlessness on body functions such as bone loss, circulation, respiration and immune system response.
The decision to network the payloads required that EADS upgrade the network from an old Cabletron hub LAN operating at 10M bps to a faster 100M bps LAN, according to Rolf Schmidhuber, Columbus data management system technology leader for EADS Space Transportation in Bremen, Germany.
"Originally we only had connected our computers with the 10 megabit LAN, but we felt it wasn't fast enough. We wanted higher performance for the payloads. So we built the system to support scientific payloads accommodated in 19 inch racks, with those payloads connected to the LAN," he said.
EADS Space Transportation selected the ProCurve 2524 LAN switches after evaluating switches from Avaya, Cisco, D-Link, Netgear and 3Com. The ProCurve 2524 switches were selected for their performance, reliability, robustness, resistance to radiation and mechanical disruption and management functions.
"We focused on vendors that could provide a small box with few electronic components [to minimize] potential radiation problems," Schmidhuber. "In radiation tests we did in Switzerland, we found that HP was the best of those we had [evaluated]. And some of the other switches could not be programmed or adjusted as HP's could."
Although EADS Space Transportation had to make some changes to the ProCurve 2524 switches, including eliminating the sheet metal enclosure, Schmidhuber said they are the first commercial switches in space.
"We have taken the ProCurve as it is, without electrical modifications. The only thing we modified is the cooling method. We removed the heat sink in the switching fabric and substituted it with copper strips that conduct the heat to the housing ground plate," he said.
EADS Space Transportation technicians also designed an aluminum enclosure to house the switches that can withstand intense vibration. "We built a structure so that vibration doesn't destroy the box," Schmidhuber said.
Reliability is key in the LAN, because if it fails, the scientific experiments fail. But EADS after extensive testing has "every confidence" in the ProCurve switch, Schmidhuber said.
In addition to connecting the payloads within the Columbus research module, the LAN also connects to computers in the ISS via a specific VLAN attached to the ISS's own LAN.
Data from the Columbus payloads will be distributed to all the computers on the system, so that they'll all have the same information, Schmidhuber said. "There's a main computer that collects all the system data, then this information will be distributed to all the other computers."
The payload data will also be transferred to the ISS LAN, which is attached to a satellite downlink for transmission to experimenters on the ground. The payload data will go to the Columbus Control Center in Oberpfaffenhofen, Germany.