Story Continues BelowLaunch of SDO was supposed to take place on Wednesday, but high winds gusting over 30 mph exceeded the limits of the rocket's flight control system. The launch team held the countdown at the built-in hold at T-4 minutes while waiting for a break in the wind. Finally, at the end of the launch window, it appeared Atlas might be able to take flight, but one second after picking up the count, another gust of wind caused the rocket's computer to call a halt to the count, forcing a 24 hour scrub.

The wind was still strong Thursday, but not nearly as strong as the day before and, after a briefly extended T-4 hold, NASA gave the final "go" for launch.

The $848 million dollar Solar Dynamics Observatory began its five-year mission at 10:23 a.m. EST when the 191-foot tall Atlas 5 launch vehicle's Russian-built RD-180 engine roared to life under the power of kerosene and liquid oxygen propellant.

The Atlas rose majestically through scattered clouds, the the morning Sun glinting off its forst-sovered metal skin.

Four minutes later, the first stage Atlas shut down as planned and the second stage Centaur fired up burning cryogenic high-energy liquid hydrogen and oxygen for the first of two burns, this one lasting 11 minutes.

Eighty-seven minutes later, the Centaur fired up a second time to place SDO into a transfer orbit with an apogee, or high point, 21,945 miles high and a low point, or perigee, at 1,552 miles with an orbital inclination of 28.5 degrees to the Equator.

Spacecraft separation occurred at 12:11 p.m. EST to begin a 3-months of final maneuvcering and on-orbit checkout of SDO before the spacecraft begins its mission to study the complex dynamics of the Sun and its magnetic field.

"The 45th Space Wing is pleased to participate with NASA and our mission partners to launch this important solar observatory," said Brig. Gen. Edward L. Bolton, Jr., 45th Space Wing commander. "We are proud to support NASA's scientific missions to unlock the secrets of the universe."

"In the two years I've been the Mission Support Lead for the 5th Space Launch Squadron I've had the opportunity to see our team progress from one launch during 2008 to eight launches in 2009," said 1st Lt. Marcella Mueth. "This year's launch forecast looks even more promising."

SDO will spend the next three weeks maneuvering itself into its final orbit. The spacecraft will fire its onboard thrusters a half-dozen times to raise its orbit to geostationary altitude 22,000 miles high.

From there, SDO will appear to make a figure-eight pattern over the Earth, moving from 28.5 degrees North Latittude to 28.5 degrees South. THe pattern wil designed to maximize the amount of time the Sun is visible to SDO which will periodically be blocked from view by Earth.

SDO's orbit is essentially geostationary and it will remain in view of the ground station at White Sands, New Mexico 24 hours a day.

The most technologically advanced of NASA's heliophysics spacecraft, SDO will take images of the sun every 0.75 seconds and daily send back about 1.5 terabytes of data to Earth -- the equivalent of streaming 380 full-length movies.

In fact, SDO will generate so much data that it will have to be downlinked to the ground in real-time because of the sheer volume.

"Because we have so much data, we don't have an on-board recorder," Citrin said. "There is no recorder that can handle this volume of data, so we have to send our data directly down to the ground."

A primary mission of the Solar Dynamics Observatory is to study the events on and near the Sun's surface to get an indirect look inside Earth's nearest star in order to understand how the Sun's magnetic field and solar storms are formed.

Solar storms generate ultra-high energy streams of charged particles the zoom out from the Sun at millions of miles per hour, propelled by the Sun's magnetic field and solar wind.

When these "waves" reach Earth and interact with the planet's own magnetic field they can generate the beautiful northern and southern lights as the charged particles stream toward Earth at the north and south pole, guided by the magnetic field around the planet.

More importantly, solar storms can cause massive distruptions to cities' electrical grids, communications and satellites in orbit, including the Global Positioning System and result in service outages across large swaths of land.

The mission of SDO is to study the Sun's weather in the hopes of giving scientists insight into how and when solar storms will erupt, thereby increasing the warning time to utilities, telecommunications companies and governments around the world.

"Understanding solar variability is crucial," says Lika Guhathakurta of Washington DC. "Our modern way of life depends upon it."

The 11-year solar cycle is largely unpredictable. It's not even 11 years long! No one knows when the next big solar storm will come.

"The solar minimum of 2008-2009 has taken us by surprise," says David Hathaway of the Marshall Space Flight Center. "It highlights how far we still have to go to successfully forecast the solar cycle."

SDO will observe the Sun faster, deeper, and in greater detail than previous observatories, breaking barriers of time-scale and clarity that have long blocked progress in forecasting dangerous solar storms.

"This is going to be sensational," said Richard R. Fisher, director of the Heliophysics Division at NASA Headquarters in Washington. "SDO is going to make a huge step forward in our understanding of the sun and its effects on life and society."

The Solar Dynamics Observatory is comprised of three main instruments.

The Atmospheric Imaging Assembly (AIA) is a battery of four telescopes designed to photograph the Sun's surface and atmosphere. AIA filters cover 10 different wavelength bands, or colors, selected to reveal key aspects of solar activity. AIA was built by the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL), Palo Alto, California. AIA's Principal Investigator is Dr. Alan Title of LMSAL.

AIA is an array of four telescopes that will observe the surface and atmosphere of our star with big-screen clarity and unprecedented time resolution. It's like an IMAX® camera for the Sun.

"By some estimates, SDO will transmit as much as 50 times more science data than any mission in NASA history," says Dean Pesnell of the Goddard Space Flight Center.

Images with 10 times greater resolution than high-definition television recorded every 0.75 seconds will reveal every nuance of solar activity.

"Because such fast cadences have never been attempted before by an orbiting observatory," Pesnell adds, "the potential for discovery is great."

AIA will produce a high-definition image of the Sun in eight selected wavelengths out of the ten available every 10 seconds. The ten wavelength bands include nine ultraviolet and extreme ultraviolet bands and one visible light band to reveal key aspects of solar activity. To accomplish this, AIA uses four telescopes, each of which can see details on the Sun as small as 725 km (450 mi) across-equivalent to looking at a human hair held 10 m (33 ft) away.

The Extreme Ultraviolet Variability Experiment (EVE) will measure fluctuations in the Sun's ultraviolet output. The solar extreme ultraviolet (EUV) radiation has a direct and powerful effect on Earth's upper atmosphere, heating it, puffing it up, and breaking apart atoms and molecules. Researchers don't know how fast the Sun can vary at many of these wavelengths, so they expect to make many new discoveries about flare events. EVE was built by the University of Colorado, with Dr. Tom Woods of University of Colorado as the Principal Investigator.

Solar scientists will use the Extreme ultraviolet Variability Experiment (EVE) to measure the Sun's brightness in the most variable and unpredictable part of the solar spectrum. The extreme ultraviolet, or EUV, ranges in wavelength from 0.1 to 105 nm.

EVE will allow solar scientists to monitor EUV emissions between 0.1 and 105 nm with the highest time resolution (10 seconds) and the highest spectral resolution (better than 0.1 nm) ever achieved by a space-based observatory. EVE also measures the very important Lyman a line at 121.6 nm, the single brightest line in the EUV. EVE will collect data 24 hours a day, 7 days a week, offering the first complete picture of solar EUV fluctuations that vary by factors of 2-100 over time scales of minutes.

The Helioseismic and Magnetic Imager (HMI) will map solar magnetic fields and peer beneath the Sun's opaque surface using a technique called helioseismology. A key goal of this experiment is to decipher the physics of the Sun's magnetic dynamo. HMI was built by the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL), Palo Alto, California. The Principal Investigator for HMI is Dr. Phil Scherrer of Stanford.

HMI will use the waves and magnetic field measured at the surface of the Sun to study the motions of material inside the Sun and the origins of the solar magnetic field.

Solar physicists will use HMI to measure the waves rippling across the surface of the Sun and the magnetic field that erupts through the surface of the Sun. HMI measures the Doppler shift of a spectral line (the change in a wave's frequency when the source moves toward or away from an observer) to give the velocity over the Sun's entire visible disk.

"It is like taking an ultrasound picture of a baby still inside her mother," says Dean Pesnell of the Goddard Space Flight Center, "the details are fuzzy but we can see many important things."

"There's a lot going on inside the Sun that we don't understand," says Todd Hoeksema, a solar physicist at Stanford University, where the HMI was built. "The Solar Dynamics Observatory is bound to deliver some big discoveries."

We use the wave data to study the inside of the Sun. As the waves travel through the Sun they are influenced by conditions inside the Sun. The speed of the sound waves increase where solar material is hotter, so the speed and angle at which the wave is generated determine how far it will penetrate into the solar interior. The shallower the angle, the shallower the penetration; the steeper the angle, the deeper the wave will travel. It takes about 2 hours for a sound wave to propagate through the Sun's interior. The frequency and spatial pattern the waves make on the surface indicate where the waves have traveled. Scientists learn about the temperature, chemical makeup, pressure, density, and motions of material throughout the Sun by analyzing the detailed properties of these waves.

HMI will provide the first rapid cadence measurements of the strength and direction of the solar magnetic field over the visible disk of the Sun. Scientists use this information to understand how the magnetic field is produced and, when combined with measurements from AIA, how that field produces flares and CMEs, the storms of space weather.

Thursday's launch was the 100th flight of a commercial variant of the Atlas family. It also extends the perfect success record of the Atlas 5.

"The Atlas and Centaur were flawless," said NASA Launch Director Omar Baez after launch.

"ULA is extremely proud to be a part of the SDO mission, NASA's first satellite launch of its 'Living with a Star' program," said Mark Wilkins, ULA Vice President, Atlas Product Line. "This launch culminates years of hard work by our NASA customer and our ULA launch team. It's appropriate that our 100th use of a commercial Atlas Centaur was for a NASA mission since Centaur was originally developed for NASA's lunar program."

The Centaur upper stage began launching as a NASA vehicle on top of Atlas in 1962 to land surveyor spacecraft on the Moon in preparation for manned landings by Apollo. As the original government-managed Atlas Centaur program was nearing its end, it was resurrected as a commercial vehicle in the late 1980s by General Dynamics. Upgraded versions of Atlas Centaur have been flying missions since 1990, with the SDO launch marking its 100th flight. Centaur is probably most famous for its role in NASA's recent Lunar Reconnaissance Orbiter and Lunar Crater Observation and Sensing Satellite (LRO/LCROSS) mission where it crashed into the Moon in October 2009 to help NASA confirm the presence of water at the Moon's South Pole.

"Our Atlas launches of the past two decades would not be the success they were without the Centaur upper stage conducting its mission flawlessly," Wilkins said. "We look forward to the next 100 Centaur missions."

(The Spacearium / SpaceflightNews.net)