NASA : NASA Launches Satellite to Study How Sun's Atmosphere Is Energized

NASA Launches Satellite to Study How Sun's Atmosphere Is Energized

WASHINGTON -- NASA's Interface Region Imaging Spectrograph (IRIS) spacecraft launched Thursday at 7:27 p.m. PDT (10:27 p.m. EDT) from Vandenberg Air Force Base, Calif. The mission to study the solar atmosphere was placed in orbit by an Orbital Sciences Corporation Pegasus XL rocket.

"We are thrilled to add IRIS to the suite of NASA missions studying the sun," said John Grunsfeld, NASA's associate administrator for science in Washington. "IRIS will help scientists understand the mysterious and energetic interface between the surface and corona of the sun."

IRIS is a NASA Explorer Mission to observe how solar material moves, gathers energy and heats up as it travels through a little-understood region in the sun's lower atmosphere. This interface region between the sun's photosphere and corona powers its dynamic million-degree atmosphere and drives the solar wind. The interface region also is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate.

The Pegasus XL carrying IRIS was deployed from an Orbital L-1011 carrier aircraft over the Pacific Ocean at an altitude of 39,000 feet, off the central coast of California about 100 miles northwest of Vandenberg. The rocket placed IRIS into a sun-synchronous polar orbit that will allow it to make almost continuous solar observations during its two-year mission.

The L-1011 took off from Vandenberg at 6:30 p.m. PDT and flew to the drop point over the Pacific Ocean, where the aircraft released the Pegasus XL from beneath its belly. The first stage ignited five seconds later to carry IRIS into space. IRIS successfully separated from the third stage of the Pegasus rocket at 7:40 p.m. At 8:05 p.m., the IRIS team confirmed the spacecraft had successfully deployed its solar arrays, has power and has acquired the sun, indications that all systems are operating as expected.

"Congratulations to the entire team on the successful development and deployment of the IRIS mission," said IRIS project manager Gary Kushner of the Lockheed Martin Solar and Atmospheric Laboratory in Palo Alto, Calif. "Now that IRIS is in orbit, we can begin our 30-day engineering checkout followed by a 30-day science checkout and calibration period."

IRIS is expected to start science observations upon completion of its 60-day commissioning phase. During this phase the team will check image quality and perform calibrations and other tests to ensure a successful mission.

NASA's Explorer Program at Goddard Space Flight Center in Greenbelt, Md., provides overall management of the IRIS mission. The principal investigator institution is Lockheed Martin Space Systems Advanced Technology Center. NASA's Ames Research Center will perform ground commanding and flight operations and receive science data and spacecraft telemetry.

The Smithsonian Astrophysical Observatory designed the IRIS telescope. The Norwegian Space Centre and NASA's Near Earth Network provide the ground stations using antennas at Svalbard, Norway; Fairbanks, Alaska; McMurdo, Antarctica; and Wallops Island, Va. NASA's Launch Services Program at the agency's Kennedy Space Center in Florida is responsible for the launch service procurement, including managing the launch and countdown. Orbital Sciences Corporation provided the L-1011 aircraft and Pegasus XL launch system.

For more information about the IRIS mission, visit:

http://www.nasa.gov/iris

NASA

Guillermo Gonzalo Sánchez Achutegui

ayabaca@gmail.com

ayabaca@hotmail.com

ayabaca@yahoo.com

Astronomy: NASA Scientists Find History of Asteroid Impacts in Earth Rocks

Hi My Friends: A VUELO DE UN QUINDE EL BLOG., Research by NASA and international scientists concludes giant asteroids, similar or larger than the one believed to have killed the dinosaurs, hit Earth billions of years ago with more frequency than previously thought.

NASA Scientists Find History of Asteroid Impacts in Earth Rocks :

WASHINGTON -- Research by NASA and international scientists concludes giant asteroids, similar or larger than the one believed to have killed the dinosaurs, hit Earth billions of years ago with more frequency than previously thought.

To cause the dinosaur extinction, the killer asteroid that impacted Earth 65 million years ago would have been almost 6 miles (10 kilometers) in diameter. By studying ancient rocks in Australia and using computer models, researchers estimate that approximately 70 asteroids the same size or larger impacted Earth 1.8 to 3.8 billion years ago. During the same period, approximately four similarly-sized objects hit the moon.

"This work demonstrates the power of combining sophisticated computer models with physical evidence from the past, further opening an important window to Earth's history," said Yvonne Pendleton, director of NASA's Lunar Science Institute (NLSI) at NASA's Ames Research Center at Moffett Field, Calif.

Evidence for these impacts on Earth comes from thin rock layers that contain debris of nearly spherical, sand-sized droplets called spherules. These millimeter-scale clues were formerly molten droplets ejected into space within the huge plumes created by mega-impacts on Earth. The hardened droplets then fell back to Earth, creating thin but widespread sedimentary layers known as spherule beds.
The new findings are published today in the journal Nature.

"The beds speak to an intense period of bombardment of Earth," said William Bottke principal investigator of the impact study team at the Southwest Research Institute (SwRI) in Boulder, Colo. "Their source long has been a mystery."

The team's findings support the theory Jupiter, Saturn, Uranus and Neptune formed in different orbits nearly 4.5 billion years ago, migrating to their current orbits about 4 billion years ago from the interplay of gravitational forces in the young solar system. This event triggered a solar system-wide bombardment of comets and asteroids called the "Late Heavy Bombardment." In the paper, the team created a model of the ancient main asteroid belt and tracked what would have happened when the orbits of the giant planets changed. They discovered the innermost portion of the belt became destabilized and could have delivered numerous big impacts to Earth and the moon over long time periods.

At least 12 mega-impacts produced spherule beds during the so-called Archean period 2.5 to 3.7 billion years ago, a formative time for life on Earth. Ancient spherule beds are rare finds, rarer than rocks of any other age. Most of the beds have been preserved amid mud deposited on the sea floor below the reach of waves.

The impact believed to have killed the dinosaurs was the only known collision over the past half-billion years that made a spherule layer as deep as those of the Archean period. The relative abundance of the beds supports the hypothesis for many giant asteroid impacts during Earth's early history.

The frequency of the impacts indicated in the computer models matches the number of spherule beds found in terrains with ages that are well understood. The data also hint at the possibility that the last impacts of the Late Heavy Bombardment on Earth made South Africa's Vredefort crater and Canada's Sudbury crater, both of which formed about 2 billion years ago.

"The Archean beds contain enough extraterrestrial material to rule out alternative sources for the spherules, such as volcanoes," said Bruce Simonson, a geologist from Oberlin College in Oberlin, Ohio.

The research was funded by NLSI and conducted by members or associates of NLSI's Center of Lunar Origin and Evolution, based at SwRI.

The impact study team also includes scientists from Purdue University in West Lafayette, Ind.; Charles University in Prague, Czech Republic; Observatorie de la Cote d'Azur in Nice, France; and Academia Sinica in Taipei, Taiwan.

To learn about the NLSI, visit:
http://lunarscience.arc.nasa.gov/

Guillermo Gonzalo Sánchez Achutegui

ayabaca@gmail.com

ayabaca@hotmail.com

ayabaca@yahoo.com