SOLAR DYNAMICS OBSERVATORY
The Solar Dynamics Observatory (SDO) is a NASA mission which will observe the Sun for over five years. Launched on February 11, 2010, the observatory is part of the Living With a Star (LWS) program.
The goal of the LWS program is to develop the scientific understanding
necessary to effectively address those aspects of the connected Sun–Earth
system that directly affect life and society. SDO's goal is to
understand the Sun's influence on Earth and near-Earth space by
studying the solar atmosphere on small scales of space and time and in
many wavelengths simultaneously. SDO will investigate how the Sun's magnetic field is generated and structured, how this stored magnetic energy is converted and released into the heliosphere and geospace in the form of solar wind, energetic particles, and variations in the solar irradiance.
TO THE PACIFIC OCEAN WEST OF SOUTH AMERICA. WHERE IS THE SDO NOW? FIND OUT BY GOING TO:
CORONAL HOLE: A dark croissant-shaped hole has opened up in the sun's atmosphere, and it is spewing a stream of solar wind into space.
NASA's Solar Dynamics Observatory took this picture of the vast opening during the early hours of 2011 Jan. 31st:
Researchers call this a "coronal hole." Solar rotation is turning the coronal hole toward Earth. The stream of solar wind pouring from it will swing around and hit our planet in early February,
THE ASTRONOMY PICTURE OF THE DAY FOR 2010 September 23
Credit: NASA / Goddard / SDO AIA Team
Explanation: Today, 2010 Sept 22, the Sun crosses the celestial equator heading south at 03:09 Universal Time. Known as an equinox, this astronomical event marks the first day of autumn in the northern hemisphere and spring in the south. Equinox means equal night. With the Sun on the celestial equator, Earth dwellers will experience nearly 12 hours of daylight and 12 hours of darkness. Of course, in the north the days continue to grow shorter, the Sun marching lower in the sky as winter approaches. To celebrate the equinox, consider this view of the Sun in extreme ultraviolet light from the Sun staring Solar Dynamics Observatory. Recorded 2010 Sept 22, the false-color image shows emission from highly ionized iron atoms. Loops and arcs trace the glowing plasma suspended in magnetic fields above solar active regions.----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
April 21, 2010: Warning, the images you are about to see could take your breath away.
At a press conference today in Washington DC, researchers unveiled "First Light" images from NASA's Solar Dynamics Observatory, a space telescope designed to study the sun.
"SDO is working beautifully," reports project scientist Dean Pesnell of the Goddard Space Flight Center. "This is even better than we could have dreamed."
Launched on February 11th from Cape Canaveral, the observatory has spent the past two months moving into a geosynchronous orbit and activating its instruments. As soon as SDO's telescope doors opened, the spacecraft began beaming back scenes so beautiful and puzzlingly complex that even seasoned observers were stunned.
For instance, here is one of the first things SDO saw:
An erupting prominence observed by SDO on March 30, 2010. The 29 MB movie takes a while to download, but it is worth the wait. A high-res still frame is also available.
"We've seen solar prominences before—but never quite like this," says Alan Title of Lockheed Martin, principal investigator of the Atmospheric Imaging Assembly (AIA), the observatory's main telescope array. "Some of my colleagues say they've learned new things about prominences just by watching this one movie."
SDO is the first mission of NASA's Living with a Star (LWS) program. The goal of LWS is to understand the sun as a magnetic variable star and to measure its impact on life and society on Earth. Program scientist Lika Guhathakurta of NASA headquarters envisions big things for the new observatory:
"SDO is our 'Hubble for the sun'," she says. "It promises to transform solar physics in the same way the Hubble Space Telescope has transformed astronomy and cosmology."
"No solar telescope has ever come close to the combined spatial, temporal and spectral resolution of SDO," adds Title. "This is possible because of the combination of 4096 x 4096-pixel CCDs with huge dynamic range and a geosynchronous orbit which allows SDO to observe the sun and communicate with the ground around the clock."
A full-disk multiwavelength extreme ultraviolet image of the sun taken by SDO on March 30, 2010. False colors trace different gas temperatures. Reds are relatively cool (~60,000 K); blues and greens are hotter (> 1,000,000 K). [full-resolution image]
One of the most amazing things about the observatory is its "big picture" view. SDO is able to monitor not just one small patch of sun, but rather the whole thing--full disk, atmosphere, surface, and even interior. "We're going to make connections that were impossible in the past," says Title.
As an example he offers the events of April 8th:
With SDO looking on, decaying sunspot 1060 unleashed a minor "B3-class" solar flare. A shock wave issued from the blast site and raced across the surface of the sun (movie). SDO images clearly show magnetic loops and other structures rocking back and forth when the wave passes over them. Eventually, the wave disappeared over the sun's horizon--but the show wasn't over. Four hours after the initial blast, and some 200,000 km away, a massive prominence erupted (image).
Coincidence? Not according to Title.
"As the wave swept across the surface of the sun, it de-stabilized magnetic fields it encountered en route. I believe the magnetic underpinnings of the prominence were upset by the wave, and this led to the eruption."
A seemingly insignificant B-flare triggered a massive prominence eruption halfway across the sun. This is the sort of unexpected connection that, when fully understood, could lead to big advances in space weather forecasting.
On April 8th this active region unleashed a B3-class solar flare. Click on the image to view an 8 MB movie of the flare and the subsequent shock wave that went rippling through the sun's atmosphere.
So far, SDO's prettiest pictures have come from the bank of telescopes called AIA. Other instruments on the spacecraft are working just as well—and they promise similarly exciting results.
"The Helioseismic Magnetic Imager (HMI) is performing splendidly," reports HMI principal investigator Phil Scherrer of Stanford University. "We're getting very high-quality, high signal-to-noise data."
HMI is designed to look inside the sun using a technique called helioseismology. Just as geologists use seismic waves to map the interior of our planet, solar physicists can use acoustic waves to map the interior of our star. On the sun, acoustic waves are generated by the sun's own internal motions. HMI detects the waves pulling the sun's surface back and forth, revealing indirectly what lies within.
"We're processing the data now," says Scherrer, "and soon we expect to have some nice maps of the sun's interior."
In addition to mapping the solar interior, the Helioseismic Magnetic Imager can also map magnetic fields on the sun's surface. This bipolar sunspot was observed by HMI on March 29th. White and black trace opposite magnetic polarities. The sunspot's main core (white) is about the size of Earth. [2 MB movie]
The Extreme UV Variability Experiment (EVE) is online, too, "and we're getting great data as well," says principal investigator Tom Woods of the University of Colorado, Boulder.
EVE monitors the sun where it is most variable—in the extreme UV part of the electromagnetic spectrum. At these wavelengths, the brightness of the sun can rise and fall a hundredfold in the blink of an eye, heating and "puffing up" Earth's upper atmosphere, and dragging down satellites. EVE measures these changes with unprecedented time and spectral resolution.
"EVE has already detected a number of very interesting solar flares," says Woods. "We're excited; the flares evolved in a way we didn't expect. This is something we wouldn't have seen without the capabilities of EVE." He plans to offer more details at a later date when the EVE team has had time to fully analyze the data.
Mission scientists stress that all of this is preliminary. The observatory is still being commissioned, and a good deal of testing and calibration remains to be done before regular, daily images become available in mid-May. Even more effort must be put in before hard science appears in refereed journals.
"First Light is just a first look," says Pesnell. "The best is yet to come."
A complete gallery of SDO's First Light images and data may be found at http://svs.gsfc.nasa.gov/Gallery/ SDOFirstLight.html.
The SDO spacecraft was assembled and tested at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and launched on February 11, 2010, from Cape Canaveral Air Force Station. The primary mission is scheduled to last five years and three months, with expendables expected to last for ten years. Some consider SDO to be a follow-on mission to the Solar and Heliospheric Observatory (SOHO).
SDO is a 3-axis stabilized spacecraft, with two solar arrays, and two high-gain antennas. The spacecraft includes three instruments: the Extreme Ultraviolet Variability Experiment (EVE) built in partnership with the University of Colorado at Boulder's Laboratory for Atmospheric and Space Physics (LASP), the Helioseismic and Magnetic Imager (HMI) built in partnership with Stanford University, and the Atmospheric Imaging Assembly (AIA) built in partnership with the Lockheed Martin Solar & Astrophysics Laboratory. Data which is collected by the craft will be made available as soon as possible, after it is received.
The Helioseismic and Magnetic Imager (HMI), led from Stanford University in Stanford, California, studies solar variability and characterizes the Sun's interior and the various components of magnetic activity. HMI produces data to determine the interior sources and mechanisms of solar variability and how the physical processes inside the Sun are related to surface magnetic field and activity. It also produces data to enable estimates of the coronal magnetic field for studies of variability in the extended solar atmosphere. HMI observations will enable establishing the relationships between the internal dynamics and magnetic activity in order to understand solar variability and its effects. HMI will take high-resolution measurements of the longitudinal and vector magnetic field over the entire visible disk thus extending the capabilities of the SOHO's MDI instrument.
The Extreme Ultraviolet Variability Experiment (EVE), will measure the Sun's extreme ultraviolet irradiance with improved spectral resolution, "temporal cadence", accuracy, and precision over preceding measurements made by TIMED SEE, SOHO, and SOURCE XPS. The instrument incorporates physics-based models in order to further scientific understand the relationship between solar EUV variations and magnetic variation changes in the Sun.
The Sun's output of energetic extreme ultraviolet photons is primarily what heats the Earth's upper atmosphere and creates the ionosphere. Solar EUV radiation output undergoes constant changes, both moment to moment and over the Sun's 11-year solar cycle, and these changes are important to understand because they have a significant impact on atmospheric heating, satellite drag, and communications system degradation, including disruption of the Global Positioning System. 
The EVE instrument package was built by the University of Colorado at Boulder's Laboratory for Atmospheric and Space Physics, with Dr. Tom Woods as Principal Investigator, and was delivered to Goddard Space Flight Center on September 7, 2007. The instrument provides improvements of up to 70 percent in spectral resolution measurements in the wavelengths below 30nm, and a 30 percent improvement in "time cadence" by taking measurements every 10 seconds over a 100 percent duty cycle.
The Atmospheric Imaging Assembly (AIA), led from the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL), provides full-disk imaging of the Sun in several ultraviolet and extreme ultraviolet (EUV) band passes at high spatial and temporal resolution. The four telescopes that provided the individual light feeds for the instrument were designed and built at the Smithsonian Astrophysical Observatory (SAO).
SDO will down-link science data (K-band) from its two onboard high-gain antennas, and telemetry (S-band) from its two onboard omnidirectional antennas. The ground station consists of two dedicated (redundant) 18-meter radio antennas in White Sands Missile Range,
New Mexico, constructed specifically for SDO. Mission controllers will
operate the spacecraft remotely from the Mission Operations Center at
NASA's Goddard Space Flight Center. The combined data rate will be
about 130 Mbit/s (150 Mbit/s with overhead, or 300 Msymbols/s with rate
1/2 convolutional encoding), and the craft will generate approximately
1.5 terabytes of data per day, beaming back 150 million bits of data
every second (The equivalent of about 380 full length movies which are
shot on an on-board Hollywood film studio).
See also: Launch window
NASA's Launch Services Program at Kennedy Space Center managed the payload integration and launch. The SDO launched from Cape Canaveral Air Force Station Space Launch Complex 41, utilizing an Atlas V-401 rocket with a RD-180 powered Common Core Booster, which has been developed to meet the Evolved Expendable Launch Vehicle (EELV) program requirements.
After launch, the spacecraft was placed into an orbit with an initial perigee of about 2,500 kilometres (1,600 mi). SDO will undergo a series of orbit-raising maneuvers which will adjust its orbit until the spacecraft reaches its planned circular, geosynchronous orbit at an altitude of 36,000 kilometres (22,000 mi), at 102° W longitude, inclined at 28.5°.
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