Mark Kelly on Space Shuttle Endeavour Final Launch

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All eyes have been on Cape Canaveral, where astronaut Mark Kelly will soon pilot space shuttle Endeavour on its last mission to space.

But back in October, it was Kelly's brother Scott who lifted off in a rocket to go to the International Space Station, a mission from which he has since returned. Since the space shuttle is about to be retired, from now on, all U.S. astronauts will rely on the Soviet-era Soyuz rockets Scott flew on to get to the Space Station.

Scott Kelly's brother Mark was there to watch the launch, and discuss the post Cold War era of camaraderie.

"We've been cooperating with the Russians and our other international partners for well over 10 years, to design and then build the Space Station," Mark Kelly told Fox News at the time. "The interesting thing I think is that it's not only that we have international agreements with the Russians, but these people have really become our friends."

Much has changed since that day in October.

Mark Kelly's wife, congresswoman Gabriel Giffords, was shot at an event in Tucson in January. That put Mark Kelly's plans to pilot the shuttle Endeavour's last flight in jeopardy. Giffords has since then speedily and remarkably recovered, and flew to Cape Canaveral on Friday to watch Kelly pilot the shuttle.

That flight was postponed by at least 72 hours, after NASA discovered two failed heaters in an auxiliary power unit.

"We will fly no orbiter before she's ready," said Mike Leinbach, shuttle launch director, announcing the delay. "Today she just wasn't ready to go." NASA has said the earliest Endeavour will be ready to fly is Monday afternoon. Kelly is ready.

"My mission brings up the last piece of the station, essentially," Kelly told Fox News. "So when we install the Alpha Magnetic Spectrometer on flight day four, the space station is complete," he said.

Scott Kelly was supposed to be on the space station when his brother and crew arrived with that payload, but timings have shifted, so the brothers won't overlap in space.  Still, it’s a sentimental event in that Kelly's wife Giffords is well enough to travel. And it’s the next-to-last space shuttle mission ever.

"Well, emotionally I was kind of sad that the space shuttle is going to be retired," he said. "It's an incredible vehicle, there's never been  anything like it, anything that can carry huge payloads -- over 30,000 pounds -- into orbit. So to see that capability go away is a little bit sad."

"But it's been in the plan," he said. "You know we had a couple of accidents with the space shuttle. Since it's very complex and capable, there's also a lot of ways that it can fail. So in our next vehicle, whatever it turns out to be, we hope to have something that's a little bit simpler and safer."