THE U.S.-Russian space relationship: Symbolism at any cost? U.S. ties to the International Space Station-and even Mir-are snarled by conflicting engineering methods, technological politics, and financial brinksmanship

Two space stations, one old, one new, circle the Earth, in orbits deliberately kept as far apart as possible. But the ties that bind the two, Russia's Mir and the multinational International Space Station, which is primarily funded by the United States, are becoming ever more distressingly tangled. The biggest and most obvious problems have occurred in the station's power and communications systems. A close look at how they were solved, from the component to the system level, reveals how efforts to preserve the unprecedented U.S.-Russian space partnership have engendered equally unprecedented costs, repeated last-minute revisions, and a startling lack of accountability on both sides. The cast of characters includes the components of the International Space Station (ISS) currently in space or planned for the near future: · Zarya (Russian for Dawn), the 20-ton Russian-built but U.S-financed component of the International Space Station, launched on a Russian rocket 20 November 1998. Also called FGB (for functional cargo block), it is powered by solar arrays and batteries and provides initial control and propulsion for the U.S. node module. The Russian-built Service Module, once launched, will be mated to Zarya and then take over its functions for the lifetime of the ISS. Zarya will then be demoted to serve as storage space and an interconnect structure. · Unity, a U.S. module known as a node, with six attachment ports (one at either end, four around its waist), to which modules launched in the future will be connected. It was carried into space 4 December 1998, aboard the STS-88 Shuttle mission. © 1999 IEEE.