An internal NASA report on the design of the Russian-built Zvezda Service Module, a key component of the International Space Station (ISS), has concluded that for the first 14 months of the station's operational life, its depressurisation could result in the loss of the ISS.
The crew would be unable to support several functions critical to ISS operation. The report also says that although the risk of depressurisation is low, the Zvezda module, to be launched next month, would only be able to provide crew emergency evacuation in the event of depressurisation elsewhere.
The danger will be abated by ISS Space Shuttle assembly flight 8A, which is likely to be launched in September 2001, when other modules will be able to provide crew evacuation and equipment to control operation of the station.
Safety concerns have been raised by NASA about other aspects of Russian contributions to the ISS. Zvezda's window does not meet NASA's standard for space debris impact protection, for instance.
The Zarya module, already in orbit, and Zvezda, also produce excessive noise levels. The Soyuz TM booster needs a considerable upgrade to provide an extra 300kg (660lb) lifting capability to support the launches of Soyuz TM manned ferries and unmanned Progress tankers to provide the ISS with consumables and logistics - but there is no funding.
Plans to launch seven Progress tankers a year seems over-optimistic given Russia's lack of funding, the NASA report indicates.
· A Russian Proton K booster was launched from the Baikonur Cosmodrome on 6 June, with a Gorizont communications satellite. The launch of another Proton, carrying an Express communications satellite, is due on 22 June. Zvezda is to be launched on 12 July.
Source: Flight International
