A software glitch that sidelined the space station's robot arm Thursday forced spacewalkers David Wolf and Piers Sellers to complete a tricky bit of station assembly by hand, a tough job that sent their heart rates soaring to some 170 beats per minute, Wolf said today.

The Canadarm2 space crane is healthy and ready for use during a second spacewalk Saturday to continue outfitting the new S1 solar array truss that was attached to the outpost Thursday.

But toward the end of the first spacewalk to activate and outfit the truss, the arm had to be shut down as part of planned work to wire the S1 truss into the station's electrical system. When flight controllers attempted to repower the arm using a redundant set of electronics, the arm balked because of a software problem. That forced Wolf to manually carry large television system components to the far end of S1 for installation, putting pressure on him not to bump any delicate equipment along the way.

"I'll tell you what, it was pretty tough," Wolf told CBS News today. "That was our backup technique in case such a contingency were to occur and it sure enough happened. The arm's in real good shape for tomorrow, we're planning to use it. We're putting another camera group out tomorrow with the arm, Piers will be mainly doing that. But we got plenty tired (Thursday) and I believe our heart rates got up to over 170 during that task. I think they both did. It took quite a team effort to make that happen."

Wolf said he and Sellers are well rested now, however, and ready for their second spacewalk Saturday.

"We like doing spacewalks, of course, and we like building more onto this orbiting laboratory, the international space station," Wolf said. "But we'd been in the suits maybe eight to 10 hours at that point, not all of it outside, and (it was) too much of a good thing. But today we're ready to go again and we're looking forward to getting out tomorrow."

For first-time flier Sellers, a scientist interested in the interaction of the biosphere and Earth's atmosphere, the busy timeline left little time for sightseeing. But when he did get a chance to enjoy the view from 245 miles up, he was overwhelmed.

"We had a long wait in the airlock, about four hours, so everything was calm and peaceful," he reflected. "Then I got to open the hatch and look out and it was dazzling, I was completely knocked out of my socks, which were luckily in my suit. I could see a landscape with clouds and a river and it was just huge, it was fantastic! So for the first five minutes, I was pretty much non-functional, my little brain was overloaded. But I snuck in a few peaks at the scenery during the spacewalk and it's really cool to be working on your hobby while floating over a hurricane. It's just fantastic."

Astronaut Sandra Magnus said before launch the shuttle crew hoped to bring a fresh pecan pie to the space station's three-person crew, along with fresh fruit and other treats. She asked reporters to keep the pie a secret and she said today, her station counterparts were delighted with the unexpected gift.

"They've enjoyed a lot of the fresh food we brought up," Magnus said. "I appreciate everyone's cooperation in keeping that a surprise for them, it really was a surprise! We're having a special meal together tonight so we may dip into it then or they may choose to save it for a special occasion. But they really appreciated it."

Space station commander Valery Korzun, Sergei Treschev and Peggy Whitson were launched to the station in June. They are the fifth full-time crew to live aboard the outpost and as of today, they have logged 128 days in space.

"They look great," said Wolf, a physician-astronaut who spent 128 days aboard the Russian Mir space station in 1997 and 1998. "I think the exercise equipment the life science people have gotten up here is working well, it's been a real step from the phase one shuttle-Mir program and they're looking good. Peg is just bouncing on the exercise equipment, hard."

Wolf said the Russian and U.S. segments of the station are different, reflecting the design philosophies of both nations, and added that both have different strengths and weaknesses. For Magnus, seeing the station up close and personal has been an eye-opening experience.

"The space station is a great place," she said. "I'd seen a lot of pictures so I had an idea what it would look like. But it's not the same as being here. It's just a spectacular place that is huge! Just floating through here and getting a feel for the atmosphere is just spectacular. I mean, here we are orbiting above the Earth like this doing great work with great views and we're working with great people. it's just so much fun!"

Added Sellers: "This place is spectacular. You've got to look at it as a real milestone in technical achievement."

But Wolf agreed with a reporter that the lab complex needs more than three residents to maximize its scientific potential. The station's current crew size is frozen at three because of budget issues.

"It's important that we get up to seven people eventually and get the full capability out of this laboratory," Wolf said. "We have some home runs to hit up in space. ... We have a real vision for the future and it'll take a full up, functioning laboratory so we can operate like we do on the ground. So we look forward to getting up to the full manning. But in the meantime ... we're getting what we can out of it, we're operating at maybe a third power in that regard, but we have a lot more to do to reach the vision."