ICM

Interim Control Module

A British science magazine predicts that there is a good chance that a rocket failure will accure during the construction of the ISS, causing the loss of perhaps a vital module to the ISS. The magazine has predicted that there is a 73,6 chance that one module will be lost. They say that the Americans and Russians should expect to loose 5 missions, with the Russian rockets beeing the most vurnable and the space shuttle most reliable.

The Russian Service module is a vital part of the station, scheduled to launch sometime in July 2000. This module serves as early living quarters, attitude controll and life support. If the module is seriously delayed or is lost during liftoff there will be a huge delay in the construction of the station and worst case scenario, the station may be lost if they can't get a mission to the station in time to raise the orbit.

In case of a long delay or loss of the module the Americans have a backup plan. Nasa has contracted with the Navy to build an Interim Control Module (ICM), at 156 million. The ICM could take the service modules place in orbit if something went wrong. While the ICM does not provide living quarters, it will give the station attitude and guidance controll, enabling the construction of the station to go forward. The ICM is a modifyed old "secret" spacecraft that was headed for the junk heap. It was used as a spinning upper stage to boost shuttle-launched Navy sattelites into a higher orbit.

The ICM is smaller than the Service module but has enough power to keep the station afloat. When launched it will be carried inside a cylinder container and will be deployed with the asistance of shuttle astonauts. The module has several 2,2 Kg (5 pound) thrusters reaching out from the ICM body along with a main thruster cappable of producing a force of 50 Kg (110 pounds). The ICM carries 5,5 tons (12,000 punds) of fuel. This should be enough to last a year or more, and if needed it can be refuelled.

Even if the Service module is launched on time, Nasa will probably launch the module late 2000 and use it as a auxilary propulsion unit on the sation. The ICM can also be used for many other things, for example boost the Hubble Space Telescope into a higher orbit.

In addition to building several modules for the ISS, the Russians are supposed to supply the station with 7 Progress and 2 Soyuz flights a year. Estimates say that it looks like the Russians will only be able to launch maby 5 such missions a year. Progress spacecrafts are used to deliver supplies to the station and boost it's orbit. With fewer Progress flights the ICM will be needed. The modifications to the shuttle and the most likely launch of the ICM will provide insurance against future shortage of Progress flights. Most likely only 30 of the planned 53 Progress will be launched, due to the cash strapped Russian space agency. NASA is also negotiating with Boeing to build a U.S. propulsion module at an expected cost of 350 million. It would eliminate the need for half of the currently planned Progress flights and provide a permanent solution in the event that the Service Module never arrives.

Related Info:
NASA | JSC | Shuttle | Shuttle-Mir | Mir

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