At a satellite-readying hangar outside the Kennedy Space Center on Thursday, NASA's sophisticated new Sun-studying probe was enclosed within the giant metal fairing that will shroud the craft during ascent to space atop an Atlas 5 booster next month.

Credit: Ben Cooper/Spaceflight Now

The Solar Dynamics Observatory is being prepared for launch from the Cape's Complex 41 on February 9 during a one-hour window opening at 10:30 a.m. EST (1530 GMT).

"We're excitedly nervous. We're nervously excited. It has been a long time. This mission started back in 2001. We've been ready for over a year to launch. We're ready," Dean Pesnell, the SDO project scientist, said during an interview inside the satellite cleanroom Thursday.

The United Launch Alliance-built Atlas rocket that will propel the $848 million mission into Earth orbit underwent a successful countdown test Wednesday.

"It's one more milestone on the schedule," said Rex Engelhardt, the mission integration manager from the agency's Launch Services Program.

The vehicle, riding on its mobile launching platform, was transported from the vertical assembly building to the pad just after 9 a.m. and then got fueled up in the early evening countdown.

The operation, known as a Wet Dress Rehearsal, put the rocket and its control team through a launch day demonstration to iron out the bugs before the real event in a few weeks.

SDO was shipped to Florida from the Goddard Space Flight Center last July to be checked out and primed to fly. A large portion of the time, however, was simply waiting for its delayed launch opportunity to come.

"We're ready, we are ready," said Elizabeth Citrin, the SDO project manager.

Citrin, Pesnell and Engelhardt spoke at the commercial Astrotech facility in Titusville as technicians prepared to slide the two halves of the Atlas nose cone around the 6,800-pound spacecraft. It's one of the last steps before the satellite heads to the launch site and joins its rocket.

Credit: Ben Cooper/Spaceflight Now

Whether the Atlas 5 will be cleared for launch as currently scheduled could hinge on a technical concern that managers are addressing. The issue involves Russian-made engines similar to the one that powers the Atlas first stage.

Officials could not discuss the specifics of the issue, citing limits imposed on talking publicly about the foreign-built hardware.

In any case, the actual engine installed on SDO's rocket isn't considered suspect and managers hope that ongoing analysis won't hold up the launch.

"We're confident that issue is going to be cleared," Citrin said. "There is a path to February 9."

Any possible slippage in the launch date would be only a matter of days, if additional time is needed to put the engine issue to rest, officials indicated.

"We're going to claw our way through each and every day," Engelhardt said.

"All the challenges come at the end, the bow wave you've got to kick your way through."

If activities remain on schedule, the encapsulated spacecraft will be placed atop a special shipping trailer Saturday and then hauled to the Atlas integration building Tuesday for hoisting atop the rocket.

A series of tests between the combined rocket and payload stack will follow, along with the final round of readiness reviews in the last days before launch.

The fully assembled rocket -- standing 19 stories tall -- rolls out to the pad the morning prior to liftoff for the start of the countdown.

SDO is headed to geosynchronous orbit 22,300 miles above the equator, in view of the project's data-receiving antennas in New Mexico that will collect the constant flow of imagery and data from the spacecraft 24 hours a day, 7 days a week.

The craft doesn't employ onboard recorders, using a continual downlink to the ground instead. The massive flow of solar information -- amounting to 1.5 terabytes per day -- should offer scientists new insights into the Sun's varying behavior and how the star influences conditions on Earth.

"SDO is going to send us images ten times better than high definition television," Pesnell said. "The pixel count is comparable to an IMAX movie -- an IMAX filled with the raging sun, 24 hours a day."

Additional coverage for subscribers:
VIDEO: MISSION INTRODUCTION BRIEFING PLAY
VIDEO: SOLAR DYNAMICS OBSERVATORY FUELED PLAY | HI-DEF
VIDEO: THE CENTAUR UPPER STAGE STACKED PLAY | HI-DEF
VIDEO: ATLAS ROCKET'S FIRST STAGE ERECTED PLAY | HI-DEF
VIDEO: APPENDAGES EXTENDED IN AUTO TEST PLAY | HI-DEF
VIDEO: MANUAL TEST OF TWIN SOLAR ARRAYS PLAY | HI-DEF
VIDEO: COMMUNICATIONS DISH GIMBAL TEST PLAY | HI-DEF
VIDEO: MANUAL TEST OF ANTENNA BOOM PLAY | HI-DEF
VIDEO: SPACECRAFT ARRIVES IN FLORIDA PLAY | HI-DEF
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