CAPECANAVERAL, Fla. -- Patience proved to be a virtue again Tuesday as NASA launchedan $85 million solar science mission into Earth orbit, following a frustrating18-month delay period caused by a test mishap and a series of failures with otherrockets.

Almosteverything went by the book as an Orbital Sciences Pegasus rocket carried thespace agency's High Energy Solar Spectroscopic Imager (HESSI) spacecraft intospace. It was launched some 130 miles (209 kilometers) east-southeast of CapeCanaveral Air Force Station at a height of 39,000 feet (11,890 meters) high.

Awinged, three-stage rocket that is airdropped from the belly of OrbitalSciences' L-1011 jumbo jet dubbed Stargazer, Pegasus ignited its first stagemain engine at 3:58 p.m. EST (2058 GMT). Its nearly 10-minute climb into orbit tookthe rocket on a path east-northeast over the Atlantic Ocean.

"Wehave HESSI in orbit," NASA launch commentator George Diller declared asofficials at the Mission Director's Center in Hangar AE of the air stationapplauded and cheered the success.

Launchwas delayed about a half-hour because of problems communicating with Stargazerduring the critical moments just before the drop. Mission managers aborted theattempt, recycled the countdown, fixed the trouble and set up for anotherattempt, which proved to be successful.

ANASA T-38 chase plane equipped with television cameras captured the momentPegasus was released from Stargazer and dropped for five seconds before firingits first stage to trail a long tail of fire and smoke across the deep bluesky.

Thesight apparently went unseen along Florida's Space Coast, where the distanceoffshore and cloudy skies conspired to prevent a clear view of the unusualspace shot for hundreds of spectators who gathered along Cape beaches to seewhat they thought was a "normal" launch from the space center.

Pegasusmissions have been staged from the Canaveral Spaceport only twice before.Commercial launches for Brazil were flown from the Cape in 1993 and 1998.

Agencymanagers said they were thrilled with the way Pegasus performed Tuesday and arelooking forward to getting the HESSI mission started.

"Everythinglooks great and the spacecraft is on its way," said Omar Baez, HESSIlaunch director. "A perfect flight."

Solarscience

Weighingin at a relatively light 645 pounds (290 kilograms), HESSI is equipped withwhat amounts to the world's first color X-ray movie camera that will enableresearchers to produce films of solar flares erupting with the force of a hundredmillion hydrogen bombs.

Generatingwhat appears as giant fingers of flame reaching out from the sun's surface,solar flares act like a giant particle accelerator that blast warp-speed wavesof subatomic particles out toward the planets, creating high-altitude havoc inEarth's upper atmosphere.

Solarflares can shut down satellites or disable aircraft navigation devices. Theyfrequently interrupt high-frequency radio communications and also exposeorbiting astronauts -- particularly spacewalkers -- to high doses of deadlycosmic radiation.

What'smore, the unpredictable outbursts often are accompanied by coronal massejections -- billion-ton clouds of gas that billow away from the sun,triggering geomagnetic storms that can knock out power grids that transmitelectricity to homes and businesses.

HESSIwill seek to solve some of the mysteries surrounding solar flares.

"Wewant to understand how these explosions actually work. How do they happen? Whydo they explode? And how can they release so much energy?" said RobertLin, a solar physicist at the University of California at Berkeley.

"Ifwe knew what the conditions were that preceded these explosions, then we couldlook for them and perhaps be able to predict when they might happen. And that,of course, would be of great benefit for our advanced technological society ingeneral," Lin said.

Programdelays

HESSI'slong road to reach orbit included several bumps along the way.

First,the HESSI satellite was accidentally shaken apart during a March 2000 vibrationtest at NASA's Jet Propulsion Laboratory in Pasadena, Calif. Designed towithstand double the force of gravity, the spacecraft was exposed to 10 timesthat limit when a testing table malfunctioned.

AMarch 2001 launch then was scheduled, but the mission was pushed back byanother three months when problems cropped up during a separate launch of thesame type of Pegasus rocket slated to carry HESSI into space.

Thenin June 2001, a Pegasus rocket and its payload - NASA's experimental X-43hypersonic test vehicle - were destroyed during a launch over the PacificOcean, casting new doubt on HESSI's launcher and indefinitely delaying itsmission.

Bythe end of 2001, mission managers were targeting a January 24 launch, but thena national missile defense system test failure in December prompted officialsto delay another month because some of the components used on the Pegasus weremade by the same company that built some of the parts suspected in the failedtest.

OrbitalSciences hopes to launch several more Pegasus vehicles this year, with the nexttargeted for mid July.

CapeCanaveral Bureau Chief Todd Halvorson contributed to this story.