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For more information contact:

Bill Steigerwald
NASA Goddard Space Flight Center
(Phone: 301/286-5017)

Donald Savage
Headquarters, Washington
(Phone: 202/358-1727)

VAULT Project website

NASA Sounding Rocket Program website

 



Viewable Images

Caption for Images 1-3 /Visualizations 1 and 2: These two visualizations show data from the satellites and VAULT (rectangular inset) from June 14, 2002. On the second visualization, the zoom shows an active area of the chromosphere. Image 3 is a zoom of a quiet region. Orange full Sun: SOHO/MDI. Yellow data: SOHO/EIT 284 angstroms. Orange data: SOHO/EIT 304 angstroms. Blue data: TRACE 171 angstroms. Orange-red inset and zooms: VAULT 171 angstroms. Credit: NASA/NRL/ESA/LMSAL

High Resolution of Image 1 (14 MB)

High Resolution of Image 2 (14 MB)

High Resolution of Image 3 (14 MB)

Caption for Image 4: Close-up images reveal an active surface with coronal loops emerging and disappearing all over the Sun's surface and can span a length of about 250,000 miles, or about 30 times the diameter of Earth. SUPER: NASA / LMSAL

Caption for Images 4 and 5: EARTH-BOUND SHOTS OF PLASMA
These views came from two instruments on the Solar and Heliospheric Observatory (SOHO) spacecraft on April 21. The first shows a full-disk image of the Sun from the Extreme ultraviolet Imaging Telescope (EIT) showing the 'explosion' on the Sun of the X-class flare. The latter image is from the Large Angle Spectrometric Coronograph (LASCO) instrument on SOHO which mimics an eclipse to study the Sun's corona, that wispy white atmosphere of the Sun. SUPER: NASA / ESA

Caption for Image 7: What is a CME?
The largest explosions in the solar system, CMEs launch up to 10 billion tons of ionized gas into space at speeds of one to two million miles an hour. SUPER: NASA

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July 08, 2003 - (date of web publication)

ROCKET TELESCOPE GETS CLOSEST LOOK AT THE SUN

 

VAULT image

Image 1/Visualization 1

Click on image for visualization.

Scientists got their closest-ever ultraviolet look at the Sun from space, thanks to a telescope and camera launched aboard a sounding rocket. The images revealed an unexpectedly high level of activity in a lower layer of the Sun's atmosphere (chromosphere). The pictures will help researchers answer one of their most burning questions about how the Sun works: how its outer atmosphere (corona) heats up to over one million degrees Celsius (1.8 million Fahrenheit), 100 times hotter than the chromosphere.

A team of Naval Research Laboratory (NRL) scientists used the Very high Angular resolution ULtraviolet Telescope (VAULT) to take pictures of ultraviolet (UV) light (1216 Å) emitted from the upper chromosphere. Resolving areas as small as 240 kilometers (150 miles or 0.3 arcseconds) on each side, the June 14, 2002, flight captured images about three times better than the previous-best pictures from space. A few ground-based telescopes can observe the Sun in 150-kilometer (93-mile) increments, but only at visible wavelengths of light. UV and X-ray wavelength observations most directly matter to solar weather.

 

image of the active region

Image 2 (active region) /Visualization 2

Click on image for visualization

Since most solar weather originates as explosions of the electrified gas (plasma) in the corona, understanding the heating and magnetic activity of the coronal plasmas will lead to better predictions of solar weather events. Severe solar weather, like solar flares and coronal mass ejections, can disrupt satellites and power grids, affecting life on Earth.

The VAULT observations reveal a highly structured, dynamic upper chromosphere, with structures visible for the first time thanks to the detailed resolution. A large number of structures in the pictures change rapidly from one image to the next, 17 seconds later. Scientists previously thought these changes occurred over five minutes or more. The transience of the physical processes in this layer has significant theoretical implications, such as the fact that proposed heating mechanisms must now also be effective over relatively short time scales.

 

image of the quiet region

Image 3 (quiet region)

Scientists found chromospheric features in the VAULT images that match features, based on shape and spatial correlation, which they see in Transition Region And Coronal Explorer (TRACE) satellite images of the corona taken simultaneously. This comparison shows that these two layers have much higher correlation than previously thought and implies that similar physical processes likely heat each. However, theory predicts the activity in the chromosphere should be lower than what scientists observed in the VAULT emissions. "[There are] more things happening below [in the upper chromosphere] than you see in the corona," says VAULT project scientist Angelos Vourlidas of the NRL.

 

TRACE coronal loops

Image 4

Click on image for visualization.

VAULT also revealed unexpected structures in quiet areas of the Sun. The plasma and magnetic field bubble up like boiling water on the Sun's visible surface (photosphere), and, like bubbles gathering and forming a ring at the edge of a pot, the field builds up in rings (network cells) in the quiet areas. VAULT captured images of smaller features and significant activity within the network cells, surprising scientists.

 

image of solar plasma

Images 5 and 6 (Click on images for visualizations.)

image of the Sun from LASCO

The telescope took 21 images in the Lyman-alpha wavelength of the electromagnetic spectrum during a six-minute-nine-second picture-taking window on its 15-minute flight. Offering the brightest solar emissions, the Lyman-alpha wavelength assured the best likelihood for pictures from the rocket and allowed for shorter exposure times and more pictures. An increase in Lyman-alpha radiation may indicate an increase in solar radiation reaching Earth.

The VAULT payload consists of a 30-centimeter (11.8-inch) Cassegrain telescope with a dedicated Lyman-alpha spectroheliograph focusing images onto a charge-coupled device (CCD) camera. The CCD, also employed in consumer digital cameras, has a photosensitivity 320 times greater than photographic film previously used. The Normal Incidence X-ray Telescope (NIXT) from the Harvard-Smithsonian Center for Astrophysics took the previous best-resolution pictures of the Sun from space in September 1989, also aboard a sounding rocket.

 

image of a coronal mass ejection

Image 7

Click on image for visualization.

The scientists verified the payload performance with an engineering flight from White Sands Missile Range, N.M., May 7, 1999. The June 14, 2002, flight from White Sands was the first scientific flight of the payload. The NRL team led a campaign combining observations from satellites and ground-based instruments. Scientists plan a third launch in Summer 2004. The mission was conducted through NASA's Sounding Rocket Program.

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