Following two U.S. spacewalks to repair the International Space Station's cooling system, two Russian cosmonauts are closing out the year in orbit with a spacewalk Friday to install two cameras on the hull of the Zvezda command module, along with a space physics experiment and a new payload support boom.

Expedition 38 commander Oleg Kotov and flight engineer Sergey Ryazanskiy opened the hatch of the Russian Pirs airlock compartment at 8 a.m. EST (GMT-5) to begin a planned seven-hour spacewalk, the third in less than a week for the station's six-man crew.

Kotov, call sign EV-1, and Ryazanskiy, EV-2, both are wearing Russian Orlan spacesuits with blue stripes and both are equipped with NASA-supplied helmet cameras to give Russian flight controllers a ringside seat.

This is the 177th spacewalk devoted to station assembly and maintenance since construction began in 1998, the 11th and final planned outing this year, the fifth for Kotov and the second for Ryazanskiy.

The first items on the agenda are to install a pair of cameras on the hull of the Zvezda module as part of a commercial venture with a Canadian company -- UrtheCast -- to beam down Earth views using high-resolution and medium-resolution cameras.

Based in Vancouver, UrtheCast (pronounced Earth Cast) says anyone with internet access will be able to download imagery of selected targets using cell phones, tablets or personal computers as the space station flies 51.6 degrees to either side of the equator at an altitude of around 260 miles.

The medium-resolution camera will provide a fixed view of the ground below while the high-resolution 4K camera will be mounted on a platform that can be aimed at specific targets. The company plans to provide basic imagery free of charge while more specific imaging requests will be billed at yet-to-be-specified rates.

"Having a platform on the ISS gives us a really neutral place to let the world observe itself without having a single governmental organization control that data," the company’s director of technology, Dan Lopez, said in an interview with CBSNews.com.

According to BC Business Online, the company is promoting an open Application Program Interface, or API, "which will allow developers to build products of its live-stream, and has signed data distribution agreements worth between $19 and $21 million."

BC Business also said UrtheCast had secured a $35 million insurance policy "for the launch, installation, commissioning and business interruption of its two cameras aboard the ISS." If the cameras fail to work properly or cannot be installed, the company would use the insurance coverage to build and launch a fresh set of cameras.

But it is not yet clear how much bandwidth UrtheCast will be provided by the Russians to get the imagery back to Earth. The Russians rely on a handful of ground stations for direct communications and do not have a globe-spanning satellite communications network like the one NASA uses to stay in contact with the station on a near-continuous basis.

Mike Suffredini, space station program manager at the Johnson Space Center in Houston, said NASA and Russian space officials were in negotiations over how much U.S. bandwidth the Russians will be able to provide.

"We're working some deals with them about how much bandwidth they want to get from us in a barter arrangement," Suffredini told CollectSpace.com Dec. 18. "You know, they would say 'I want a hundred gigs all the time' and we'd say, 'you can't have a hundred gigs all the time.'

"But we'll find a healthy spot there. The Russians, that's something they have to barter for because that is an asset that we use. But they've been talking to us about it. And we've been working back and forth with them to decide."

He said NASA has "some things that we want and they're willing to trade, so it is just (a matter of) getting it done. It is not a contentious issue."

Once the cameras are installed, Kotov and Ryazanskiy will turn their attention to installing a new space physics experiment and jettisoning two others that have run their course. They also plan to attach a new payload support boom.