• 2010 nasa special
    a total eclipse of the Sun is visible from within a narrow corridor that traverses Earth's southern Hemisphere. The path of the Moon's umbral shadow crosses the South Pacific Ocean where it makes no landfall except for Mangaia (Cook Islands) and Easter Island (Isla de Pascua).
Showing posts with label Nasa News Updates. Show all posts
Showing posts with label Nasa News Updates. Show all posts

NASA says no new launch attempt before next Sunday

1:52 AM Nasa Information , Posted in , , , , , , 0 Comments

NASA says no new launch attempt before next Sunday (AP)

 NASA says no new launch attempt before next Sunday (AP)

 







NASA's space shuttles are dragging their tails toward retirement.

The high-profile voyage of Endeavour - the next-to-last space shuttle flight led by the husband of wounded Rep. Gabrielle Giffords - is off until at least next Sunday because of a technical problem. The latest culprit, believed to be a bad fuse box, illustrates just how complex these space machines are and why NASA's goodbye to the 30-year shuttle program may be a long one.

Commander Mark Kelly and his five crewmates quickly headed back to Houston on Sunday morning, two days after their first launch attempt was foiled.

Giffords wasn't far behind; she was in Houston by midafternoon, ready to resume rehab at the hospital where she's been undergoing treatment since January, after being shot in the head in an assassination attempt. She had arrived in Florida Wednesday to take part in the excitement of the launch countdown and to see her husband blast off. It was not immediately known if she would be back for a second try.

Her presence added to the drama surrounding Endeavour's liftoff. So did that of President Barack Obama and his family. They were disappointed not to see a launch on Friday, but still dropped by for a tour at Kennedy Space Center anyway. Obama hinted he might make a return visit to see the very last shuttle launch this summer.

The tip-off that Endeavour had a problem was the failure of heaters that are crucial for keeping a fuel line from freezing in space. The launch was called off Friday as the astronauts headed to the pad to board the shuttle. NASA has now traced the problem to the switch box.

Over the decades, space shuttles have encountered all sorts of technical problems, from nose to tail, that have held up launches. So have problems with their tanks and booster rockets.

Fuel leaks. Engine shutdowns. Wiring problems. Stuck valves. Burst hoses. Turbine failures. Hail damage, even woodpecker holes in the insulating foam of fuel tanks. 

NASA Orbiter Reveals Big Changes in Mars' Atmosphere

12:31 AM Nasa Information , Posted in , , , , 0 Comments

Thickness map of buried carbon-dioxide deposit 

A newly found, buried deposit of frozen carbon dioxide -- dry ice -- near the south pole of Mars contains about 30 times more carbon dioxide than previously estimated to be frozen near the pole. Image credit: NASA/JPL-Caltech/Sapienza University of Rome/Southwest Research Institute

Cross section of buried carbon-dioxide ice on Mars 

This cross-section view of underground layers near Mars' south pole is a radargram based on data from the Shallow Subsurface Radar (SHARAD) instrument on NASA's Mars Reconnaissance Orbiter. Image credit: NASA/JPL-Caltech/Sapienza University of Rome/Southwest Research Institute

Pitting from sublimation of underlying dry-ice layer 

These images from orbit show an area near Mars' south pole where coalescing or elongated pits are interpreted as signs that an underlying deposit of frozen carbon dioxide, or "dry ice," has been shrinking by sublimation. Image credit: NASA/JPL-Caltech/Univ. of Arizona


PASADENA, Calif. -- NASA's Mars Reconnaissance Orbiter has discovered the total amount of atmosphere on Mars changes dramatically as the tilt of the planet's axis varies. This process can affect the stability of liquid water, if it exists on the Martian surface, and increase the frequency and severity of Martian dust storms. 

Researchers using the orbiter's ground-penetrating radar identified a large, buried deposit of frozen carbon dioxide, or dry ice, at the Red Planet's south pole. The scientists suspect that much of this carbon dioxide enters the planet's atmosphere and swells the atmosphere's mass when Mars' tilt increases. 

The findings are published in this week's issue of the journal Science.
The newly found deposit has a volume similar to Lake Superior's nearly 3,000 cubic miles (about 12,000 cubic kilometers). The deposit holds up to 80 percent as much carbon dioxide as today's Martian atmosphere. Collapse pits caused by dry ice sublimation and other clues suggest the deposit is in a dissipating phase, adding gas to the atmosphere each year. Mars' atmosphere is about 95 percent carbon dioxide, in contrast to Earth's much thicker atmosphere, which is less than .04 percent carbon dioxide. 

"We already knew there is a small perennial cap of carbon-dioxide ice on top of the water ice there, but this buried deposit has about 30 times more dry ice than previously estimated," said Roger Phillips of Southwest Research Institute in Boulder, Colo. Phillips is deputy team leader for the Mars Reconnaissance Orbiter's Shallow Radar instrument and lead author of the report.
"We identified the deposit as dry ice by determining the radar signature fit the radio-wave transmission characteristics of frozen carbon dioxide far better than the characteristics of frozen water," said Roberto Seu of Sapienza University of Rome, team leader for the Shallow Radar and a co-author of the new report. Additional evidence came from correlating the deposit to visible sublimation features typical of dry ice. 

"When you include this buried deposit, Martian carbon dioxide right now is roughly half frozen and half in the atmosphere, but at other times it can be nearly all frozen or nearly all in the atmosphere," Phillips said. 

An occasional increase in the atmosphere would strengthen winds, lofting more dust and leading to more frequent and more intense dust storms. Another result is an expanded area on the planet's surface where liquid water could persist without boiling. Modeling based on known variation in the tilt of Mars' axis suggests several-fold changes in the total mass of the planet's atmosphere can happen on time frames of 100,000 years or less. 

The changes in atmospheric density caused by the carbon-dioxide increase also would amplify some effects of the changes caused by the tilt. Researchers plugged the mass of the buried carbon-dioxide deposit into climate models for the period when Mars' tilt and orbital properties maximize the amount of summer sunshine hitting the south pole. They found at such times, global, year-round average air pressure is approximately 75 percent greater than the current level. 

"A tilted Mars with a thicker carbon-dioxide atmosphere causes a greenhouse effect that tries to warm the Martian surface, while thicker and longer-lived polar ice caps try to cool it," said co-author Robert Haberle, a planetary scientist at NASA's Ames Research Center in Moffett Field, Calif. "Our simulations show the polar caps cool more than the greenhouse warms. Unlike Earth, which has a thick, moist atmosphere that produces a strong greenhouse effect, Mars' atmosphere is too thin and dry to produce as strong a greenhouse effect as Earth's, even when you double its carbon-dioxide content." 

The Shallow Radar, one of the Mars Reconnaissance Orbiter's six instruments, was provided by the Italian Space Agency, and its operations are led by the Department of Information Engineering, Electronics and Telecommunications at Sapienza University of Rome. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter project for NASA's Science Mission Directorate at the agency's headquarters in Washington. Lockheed Martin Space Systems in Denver built the spacecraft.
For more information about the Mars Reconnaissance Orbiter mission, visit http://www.nasa.gov/mro .
 
 
Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov

Maria Martinez 210-522-3305
Southwest Research Institute, San Antonio, Texas
maria.martinez@swri.org

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov

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