International Space Station program with on-orbit refurbishment in mind. According to the Outer Space Treaty the United States is legally responsible for all modules it has launched. In ISS planning, NASA examined options including returning the station to Earth via shuttle missions (deemed too expensive, as the station(USOS) is not designed for disassembly and this would require at least 27 shuttle missions), natural orbital decay with random reentry similar to Skylab, boosting the station to a higher altitude (which would simply delay reentry) and a controlled targeted de-orbit to a remote ocean area. The technical feasibility of a controlled targeted deorbit into a remote
International Space Station core of the cancelled Mir-2 space station, the hull of "Zvezda" was completed in February 1985, with major internal equipment installed by October 1986. The module was launched by a Proton-K rocket from Site 81/23 at Baikonur, on 12 July 2000. "Zvezda" is at the rear of the station according to its normal direction of travel and orientation, and its engines may be used to boost the station's orbit. Alternatively Russian and European spacecraft can dock to "Zvezda" aft port and use their engines to boost the station. Destiny, also known as the U.S. Lab, is the primary research facility