Thursday, September 24, 2009

Space Shuttle Mission

At NASA's Kennedy Space Center in Florida, technicians are preparing space shuttle Atlantis for its move from Orbiter Processing Facility-1 to the Vehicle Assembly Building, or VAB, next month.

Final preparations in the shuttle's aft section are complete and crews are working on the forward sections now. The main landing gear is set to be leak tested and the hydraulic fluid level will be checked today.

Battery installation and testing for the wing leading edge sensors is ongoing. The sensors help monitor the reinforced carbon carbon heat shield panels on the shuttle’s wings for possible debris impacts. The payload bay doors will be closed Friday for rollover.

Meanwhile in the VAB, Atlantis' external fuel tank and solid rocket boosters have been stacked on the mobile launcher platform in High Bay 2.

Friday, September 18, 2009

Hubble Opens New Eyes on the space

NASA's Hubble Space Telescope is back in business, ready to uncover new worlds, peer ever deeper into space, and even map the invisible backbone of the universe.

The first snapshots from the refurbished Hubble showcase the 19-year-old telescope's new vision. Topping the list of exciting new views are colorful multi-wavelength pictures of far- flung galaxies, a densely packed star cluster, an eerie "pillar of creation," and a "butterfly" nebula.

With the release of these images, astronomers have declared Hubble a fully rejuvenated observatory. Sen. Barbara A. Mikulski, D-Md., unveiled the images at NASA Headquarters in Washington, D.C., on Sept. 9, 2009.

With its new imaging camera, Hubble can view galaxies, star clusters, and other objects across a wide swath of the electromagnetic spectrum, from ultraviolet to near-infrared light. A new spectrograph slices across billions of light-years to map the filamentary structure of the universe and trace the distribution of elements that are fundamental to life.

The telescope's new instruments also are more sensitive to light and can observe in ways that are significantly more efficient and require less observing time than previous generations of Hubble instruments.

NASA astronauts installed the new instruments during the space shuttle servicing mission in May 2009. Besides adding the instruments, the astronauts also completed a dizzying list of other chores that included performing unprecedented repairs on two other science instruments.

Now that Hubble has reopened for business, it will tackle a whole range of observations. Looking closer to Earth, such observations will include taking a census of the population of Kuiper Belt objects residing at the fringe of our solar system, witnessing the birth of planets around other stars, and probing the composition and structure of the atmospheres of other worlds.

Peering much farther away, astronomers have ambitious plans to use Hubble to make the deepest-ever portrait of the universe in near-infrared light. The resulting picture may reveal never-before-seen infant galaxies that existed when the universe was less than 500 million years old. Hubble also is now significantly more well-equipped to probe and further characterize the behavior of dark energy, a mysterious and little-understood repulsive force that is pushing the universe apart at an ever-faster rate.

Friday, September 11, 2009

Longest Solar Eclipse of the 21st Century

One one-thousand, 2 one-thousand, 3 one-thousand, 4 one-thousand...Continue counting and don't stop until you reach 399 one-thousand. Did that feel like a long time? Six minutes and 39 seconds to be exact. That's the duration of this week's total solar eclipse--the longest of the 21st century.

The event begins at the crack of dawn on Wednesday, July 22nd, in the Gulf of Khambhat just east of India. Morning fishermen will experience a sunrise like nothing they've ever seen before. Rising out of the waves in place of the usual sun will be an inky-black hole surrounded by pale streamers splayed across the sky. Sea birds will stop squawking, unsure if the day is beginning or not, as a strange shadow pushes back the dawn and stirs up a breeze of unaccustomed chill.

Most solar eclipses produce this sort of surreal experience for a few minutes at most. The eclipse of July 22, 2009, however, will last as long as 6 minutes and 39 seconds in some places, not far short of the 7 and a half minute theoretical maximum. It won't be surpassed in duration until the eclipse of June 13, 2132.

From the Gulf of Khambhat, the Moon's shadow will race east across India, China, and the Ryukyu Islands of Japan. Click on the image to launch an animated map:

The path of totality cuts across many large cities. The shadow will linger over Shanghai, the largest city in China, for six full minutes, giving 20 million residents a lengthy and stunning view of the sun's ghostly corona. Other large cities in the path of totality include Surat, Vadodara, Bhopal, Varanasi, Chengdu, Chongqing, Wuhan, Hefei, Hangzhou. The population of each numbers in the millions, making this possibly the best-observed solar eclipse in human history.

The eclipse is extra-long because of a lucky coincidence, made possible by the elliptical shape of planetary orbits. On July 22nd, Earth happens to be near its farthest point from the sun. A small sun means the Moon can cover it longer. At the same time, the Moon will be near its closest point to Earth. A large Moon covers the sun longer, lengthening the eclipse even more.

The leisurely pace of the eclipse could have a transformative effect on witnesses. Total eclipses have been known to turn ordinary folk into life-long "eclipse-chasers" willing to spend thousands of dollars and travel tens of thousands of miles to feel the Moon's cool shadow and behold the sun's pale atmosphere just one more time. A few extra minutes of wonder will intensify this effect to an unknown degree.

Sunday, September 06, 2009

Sea Ice May Be on Increase in the Antarctic: A Phenomenon Due to a Lot of 'Hot Air'?

A new NASA-funded study finds that predicted increases in precipitation due to warmer air temperatures from greenhouse gas emissions may actually increase sea ice volume in the Antarctic’s Southern Ocean. This adds new evidence of potential asymmetry between the two poles, and may be an indication that climate change processes may have different impact on different areas of the globe.

"Most people have heard of climate change and how rising air temperatures are melting glaciers and sea ice in the Arctic," said Dylan C. Powell, co-author of the paper and a doctoral candidate at the University of Maryland-Baltimore County. "However, findings from our simulations suggest a counterintuitive phenomenon. Some of the melt in the Arctic may be offset by increases in sea ice volume in the Antarctic.

The researchers used satellite observations for the first time, specifically from the Special Sensor Microwave/Imager, to assess snow depth on sea ice, and included the satellite observations in their model. As a result, they improved prediction of precipitation rates. By incorporating satellite observations into this new method, the researchers achieved more stable and realistic precipitation data than the typically variable data found in the polar regions. The paper was published in the June issue of the American Geophysical Union's Journal of Geophysical Research.

"On any given day, sea ice cover in the oceans of the polar regions is about the size of the U.S.," said Thorsten Markus, co-author of the paper and a research scientist at NASA’s Goddard Space Flight Center, Greenbelt, Md. "Far-flung locations like the Arctic and Antarctic actually impact our temperature and climate where we live and work on a daily basis."

According to Markus, the impact of the northernmost and southernmost parts on Earth on climate in other parts of the globe can be explained by thermohaline circulation – the movement of ocean water that is caused by temperature and salinity variations in the ocean. Through this process, ocean circulation acts like a heat pump and determines our climate to a great extent. The deep and bottom water masses of the oceans make contact with the atmosphere only at high latitudes near or at the poles. In the polar regions, the water cools down and releases its salt upon freezing, a process that also makes the water heavier. The cooler, salty, water then sinks down and cycles back towards the equator. The water is then replaced by warmer water from low and moderate latitudes, and the process then begins again.

Typically, warming of the climate leads to increased melting rates of sea ice cover and increased precipitation rates. However, in the Southern Ocean, with increased precipitation rates and deeper snow, the additional load of snow becomes so heavy that it pushes the Antarctic sea ice below sea level. This results in even more and even thicker sea ice when the snow refreezes as more ice. Therefore, the paper indicates that some climate processes, like warmer air temperatures increasing the amount of sea ice, may go against what we would normally believe would occur.

"We used computer-generated simulations to get this research result. I hope that in the future we’ll be able to verify this result with real data through a long-term ice thickness measurement campaign," said Powell. "Our goal as scientists is to collect hard data to verify what the computer model is telling us. It will be critical to know for certain whether average sea ice thickness is indeed increasing in the Antarctic as our model indicates, and to determine what environmental factors are spurring this apparent phenomenon."

Achim Stossel of the Department of Oceanography at Texas A&M University, College Station, Tex., a third co-author on this paper, advises that "while numerical models have improved considerably over the last two decades, seemingly minor processes like the snow-to-ice conversion still need to be better incorporated in models as they can have a significant impact on the results and therefore on climate predictions."

Saturday, September 05, 2009

Lighting Up the Night

Viewed from the Banana River Viewing Site at NASA's Kennedy Space Center in Florida, space shuttle Discovery arcs through a cloud-brushed sky, lighted by the trail of fire after launch on the STS-128 mission. Liftoff from Launch Pad 39A was on time at 11:59 p.m. EDT. The first launch attempt on Aug. 24 was postponed due to unfavorable weather conditions. The second attempt on Aug. 25 also was postponed due to an issue with a valve in space shuttle Discovery's main propulsion system.

The STS-128 mission is the 30th International Space Station assembly flight and the 128th space shuttle flight. The 13-day mission will deliver more than 7 tons of supplies, science racks and equipment, as well as additional environmental hardware to sustain six crew members on the International Space Station. The equipment includes a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill.