The so-called "Pirs" -- or Pier -- compartment is to arrive at the station and automatically dock itself to the outpost at 9:07 p.m. EDT Sunday (0107 GMT Monday).
NASA officials say they plan to broadcast the event live on NASA TV.
Once attached and declared operational, the module will provide outpost crews with a second orbital portal through which spacewalking repair and assembly work can be performed.
"And that is a very nice capability to have," said Jim Van Laak, a senior NASA station project manager at the agency's Johnson Space Center in Houston.
Built by Moscow-based aerospace giant RSC-Energia, the Pirs compartment will serve as an airlock for staging spacewalks from the Russian segment of the 17-story station, which now comprises five linked modules that stretch 171 feet (52 meters) from end to end.
Also known as Docking Compartment-1, the module is only equipped to service Russian space suits but will give station crews added flexibility in the event that problems crop up with the $164 million American Quest airlock that was added to the outpost in July.
"We built a very high performance airlock. The airlock that we flew (in July) is a beautiful piece of equipment. It's very thoroughly engineered and it has a great deal of capability. It's also quite complex," Van Laak said.
Consequently, the Quest airlock requires electrical power, ventilation and other support services from other station systems. And if problems were to crop up with any of the associated systems, the U.S.-built airlock could be temporarily put out of commission.
The Pirs airlock, in contrast, is much simpler in design, and as a result, it will provide a robust back-up capability in the event that Quest -- which is equipped to service either U.S. or Russian space suits -- is rendered useless.
"They designed it to be absolutely available pretty much regardless of what other systems might be affected (by problems)," Van Laak said, adding: "It's genuinely good to have redundancy."
Docked to an Earth-facing port on the station's Russian-built crew quarters, the 16-foot-long (4.85-meter-long) Pirs module is large enough to serve as a stowage closet for Russian spacesuits, tools and other equipment.
What's more, the cylindrical segment will provide an extra docking port for Russian Soyuz crew transport vehicles and Progress cargo carriers, which double as station lifeboats and disposable trash trucks, respectively.
As it stands, bug-shaped Progress carriers have to be jettisoned from the station prior to the arrival of inbound Russian space freighters.
The extra Pirs port will enable station crews to keep old Progress vehicles parked at the outpost for longer periods of time rather than sending them on destructive dives back through the atmosphere before they are entirely filled with trash.
In addition, the Pirs port will reduce the need to reposition Soyuz vehicles when a new Russian crew transport arrives at the outpost. Visiting Russian taxi crews deliver a fresh Soyuz lifeboat to the station every six months and then return to Earth in old Soyuz craft.
The station's current crew -- U.S. astronaut Frank Culbertson and Russian cosmonauts Vladimir Dezhurov and Mikhail Turin -- will outfit the exterior of the new docking compartment during three spacewalks to be performed in October and November.
The delivery of Pirs, meanwhile, will cap a busy year of assembly at the international outpost, which is a joint project of 16 space agencies in the U.S., Russia, Europe, Canada, Japan and Brazil.
The $1.4 billion U.S. Destiny laboratory, a $600 million Canadian robot arm and the American Quest airlock all have been added to the station this year.
And since July 2000, a total of 15 U.S. and Russian assembly and re-supply missions have been launched to the station during what has been one of the busiest and most challenging periods in the history of human space exploration.
"And if you look at what we accomplished, it is truly amazing," said NASA senior station project manager Bill Gerstenmaier.
Van Laak agreed. "I think it's fair to say that we've all been amazed at the progress that's been made in the last year."
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