sentences:  The STS-88 Space Shuttle mission followed two weeks after "Zarya" was launched, bringing "Unity", the first of three node modules, and connecting it to "Zarya".This bare 2-module core of the ISS remained uncrewed for the next one and a half years, until in July 2000 the Russian module "Zvezda" was launched by a Proton rocket, allowing a maximum crew of two astronauts or cosmonauts to be on the ISS permanently.The ISS has a pressurized volume of approximately , a mass of approximately , approximately 100 kilowatts of power output, a truss long, modules long, and a crew of six.