CAPE CANAVERAL, Fla. -- Shuttle Endeavours astronauts glided to a sundown landing at Kennedy Space Center Monday, capping a huge comeback year for NASAs $60 billion International Space Station construction project.

With trademark twin sonic booms signaling the astronauts arrival, Endeavour arced out over the Atlantic Ocean and then made a plunging final approach to a floodlit concrete runway.

Endeavour sweeps through the darkness to touch down at the Kennedy Space Center on Monday. Image from NASA TV.

The biggest, most powerful and most expensive solar wings ever hauled into orbit also were unfurled and activated at the 13-story outpost, quintupling the amount of electricity available to the stations first full-time crew.

"Outstanding job," astronaut Gus Loria told the astronauts from NASAs Mission Control Center in Houston. "Welcome back."

Coming 10 days, 19 hours and 58 minutes after the shuttles Nov. 30 launch, the landing marked the finish of an ambitious six-month bid to get the fledgling station up and operating in earnest.

Flying vacant since its first two building blocks were linked in orbit in late 1998, the station began to grow exponentially in July with the long-delayed delivery of a Russian crew module, which doubled the size of the outpost.

A visiting construction crew outfitted the new crew quarters in September. Another in October added a new shuttle docking port and the first piece of the stations metal backbone, which eventually will span an area longer than a football field.

The stations first tenants -- U.S. astronaut Bill Shepherd and two Russian cosmonauts, Yuri Gidzenko and Sergei Krikalev -- took up residence at the outpost Nov. 2. Then Endeavours crew showed up with the stations new American-made electrical power plant.

And in between it all, a pair of Russian space freighters trucked up to the outpost with food, water and clothing as well as tons of station equipment and other sundry supplies.

Said Shepherd: "Its been a pretty fantastic run of great missions."

What a difference a year makes.

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In December 1999, NASA was struggling to launch a Hubble Space Telescope repair mission after five months of exhaustive wiring inspections that effectively grounded the agencys entire four-orbiter shuttle fleet.

Kennedy Space Center ground crews work around the shuttle after landing. Image from NASA TV.

"And it occurred to me that here we are feasting upon the opportunity to launch shuttles on a regular basis," said NASA shuttle program manager Ron Dittemore.

The hectic pace, meanwhile, actually is expected to pick up in 2001 as NASA and its 15 international partners launch another dozen station construction and resupply flights.

Coming up next: The U.S. Destiny laboratory, which will serve as the scientific heart of the station. The bus-sized lab is to be launched aboard shuttle Atlantis in mid January.

"We are one gigantic step closer to [launching] what can be the most sophisticated laboratory ever in space," said Milt Heflin, NASAs deputy chief flight director. "We right on the brink of doing that, thanks to what weve gotten to on this mission."

A Canadian construction crane, three Italian moving vans, a spare parts warehouse and an airlock will be added on to the burgeoning complex before the winter of 2001. And by the end of next year, the outpost -- which is known by the radio call sign "Alpha" -- is expected to swell to the size of a three-bedroom ranch house.

"Were going to continue to build this space station over the coming months," said senior NASA project manager Bob Cabana. "And although its an awesome facility right now, by this time next year, it will truly be a functioning space station doing real science up there on a regular basis."

Thats not to say, however, that NASA doesnt expect a few bumps in the road -- or that the upcoming construction missions are going to get any easier.

"The complexity of the flights continues to increases as the station assembly progresses," said Dittemore. "Were going to raise the bar, so to speak, and thats going to be true on every mission we come forward with in the near future."

All in all, another 40 U.S. shuttle and Russian rocket missions will be required to build the station, which eventually will weigh 480 tons and cover an area as large as a New York city block.

Construction now is scheduled to be finished up in April 2006, and dozens of Russian resupply ships will be launched during that time to support rotating research crews.

And Endeavour mission specialist Marc Garneau -- who plans to retire from NASAs astronaut corps -- is just glad he had a hand in helping to raise the infant station.

"I think this is the beginning of something very, very big," said Garneau, who became the first Canadian to fly in space in 1984. "And when Im old and rickety and sitting in a rocking chair, Ill think back at the time that I was involved with the beginning of space station Alpha."