CAPE CANAVERAL --Kennedy Space Center took on the feel of a bustling spaceport Tuesday morningas one orbiter landed and another moved out to the launch pad.

Columbia soared through a dark Florida sky Tuesday morningon its way to a flawless landing, capping its mission to refurbish the HubbleSpace Telescope.

"Field in sighton a beautiful night," commander Scott Altman radioed as the orbiterapproached the runway at 4:32 a.m.

Pilot Duane Careyhandled the 100-ton glider for about a minute to end his first flight.

Less than four hourslater, Atlantis crept slowly to launch pad 39B for a scheduled April 4 flightto space station Alpha. Atlantis will carry the first new piece to the outpostsince last summer, and host the first astronaut to fly seven times, Jerry Ross.

The events gave KSC apreview of the next couple months when NASA flies back-to-back missions inApril and May. Another mission by Columbia awaits in July, followed by aSeptember flight.

Touching down at thesouth end of the Kennedy Space Center's 3-mile long runway, Columbia cast ashadowy silhouette through the white rays of spotlights. The return to Earthended an 11-day mission that officials said was the most complex of the shuttleera, including five spacewalks to install $172 million worth of new equipmenton the Hubble observatory.

"This exceededeverybody's expectations," NASA Administrator Sean O'Keefe said minutesafter Columbia rolled to a stop. "It was a fulfillment of what all of usbelieve NASA is capable of."

Astronomers andengineers have run tests on the new instruments since their installation, butit will take many weeks of more calibration and evaluation before they taketheir first photos of the cosmos with the rejuvenated Hubble.

A suspect coolingsystem held up during the hourlong re-entry and landing cycle. One ofColumbia's two Freon systems was partially blocked by debris, nearly forcing apremature end to the flight.

Columbia and itsFreon systems will remain turned on even after the orbiter is inside itsprocessing hangar to give technicians a chance to pull out the obstruction,United Space Alliance spokesman Jack King said.

The work may befinished in time for Columbia's July 11 launch date, Shuttle IntegrationManager Linda Hamm said.

The seven astronautsattached new solar panels to the telescope, outfitted it with an advancedcamera and upgraded its power distribution system. John Grunsfeld, Jim Newman,Rick Linnehan and Mike Massimino completed five spacewalks lasting a record35hours, 55 minutes. Nancy Currie operated the robot arm during the flight.

"The results ofthis mission really are going to be mind-blowing," O'Keefe said."It's an exciting time to be associated with a program like this, no doubtabout it."

Published under licensefrom FLORIDA TODAY. Copyright 2002 FLORIDA TODAY. No portion of this materialmay be reproduced in any way without the written consent of FLORIDA TODAY.