International Space Station

The International Space Station (ISS) is a joint project of 6 space agencies: the U.S. National Aeronautics and Space Administration (NASA), Russian Federal Space Agency, Japan Aerospace Exploration Agency (JAXA), Canadian Space Agency (CSA/ASC), Brazilian Space Agency (AEB) and the European Space Agency (ESA, with members United Kingdom, Ireland, Portugal, Austria and Finland choosing not to participate; Greece and Luxembourg joined ESA later http://www.esa.int/esaHS/partstates.html).

Present status of the ISS

After the accident of the Space Shuttle Columbia on February 1, 2003, and the subsequent two and a half year suspension of the US Space Shuttle program, followed by problems in 2005 to return to flight, there remains some uncertainty over the future of the ISS. Its construction was practically halted during the shuttle grounding as major parts of the ISS are so heavy that they cannot be lifted to the ISS by any other launcher currently in service. For example, the European Space Agency's laboratory module Columbus is ready to go, but cannot be delivered into orbit by currently available launchers. In the meantime, crew exchange was done using the Russian Soyuz spacecraft. Starting with Soyuz TMA-2, two-astronaut caretaker crews have been launched, instead of the previous crews of three. However, the Soyuz lacks the raw cargo space of the shuttle, and because the ISS had not been serviced by a shuttle for an extended period, a large amount of waste accumulated which temporarily hindered station operations.

Related Topics:
Accident - Space Shuttle Columbia - February 1 - 2003 - Space Shuttle program - 2005 - Columbus - Soyuz TMA-2 - Waste

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The Space Shuttle Program resumed flight, on 26 July 2005, with the STS-114, 'Return to Flight' mission of the shuttle Discovery. This mission to the ISS was intended to both test new safety measures implemented since the Columbia disaster, and to deliver supplies to the station.

Related Topics:
26 July - 2005 - STS-114 - Discovery

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New foam application techniques were tested on the shuttle's external tank, and a number of additional cameras were used during launch to better view any possible debris strikes to the orbiter. Once in orbit, the shuttle underwent an extensive self-examination using a new boom-mounted camera attached to the shuttle's robotic Canadarm. Prior to mating the shuttle to the ISS, a somersault maneuver was performed so that station astronauts could photograph the underside of the shuttle. Discovery did not appear to be damaged, but examination of photography during launch indicated that a large piece of foam did fall off of the external tank. NASA has stated that the shuttle will not fly again until the foam shedding issue is dealt with.

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Despite the foam problems, STS-114 continued in its mission to mate an Italian-built Multi-Purpose Logistics Module (MPLM), Raffaello, to the Unity Node of the station. The MPLM serves as a temporary pressurized module that carries new food and supplies to the station, and a depository for accumulated waste once the fresh supplies have been delivered. The MPLMs are intended to be reusable, and are returned to the shuttle's payload bay once the station waste has been loaded, and the ISS hatch to the MPLM is closed. The modules then return with the shuttle and are reloaded for future missions.

Related Topics:
STS-114 - Multi-Purpose Logistics Module - Unity Node

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STS-114 also delivered a service-rack pallet which was attached to the station. The pallet will aid astronauts performing EVAs outside of the ISS. A guidance gyroscope was also delivered to replace a faulty one currently aboard the station. The station is equipped with four such gyroscropes, but requires only two to be functional to maintain proper altitude.

Related Topics:
STS-114 - EVAs - Gyroscope - Altitude

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STS-121, another 'Return to Flight' mission using the shuttle Atlantis was scheduled for September, but has been delayed until at least March 2006, until the issue of foam debris can be resolved on the shuttle's external tank. This keeps the International Space Station's future uncertain, and further delays its construction.

Related Topics:
STS-121 - Atlantis - 2006

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The possibility of an extremely high-speed collision with space debris is considered a long-term threat to the International Space Station. One solution which has been proposed by NASA and others is a laser broom.

Related Topics:
Space debris - Laser broom

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