Thursday, January 28, 2010

Cassini's Next Look at Titan

Sixteen days after last visiting Saturn's largest moon, NASA's Cassini spacecraft returns for another look-see of the cloud-shrouded moon - this time from on high. The flyby on Thursday, Jan. 28, referred to as "T-66" in the hollowed halls of Cassini operations, will place the spacecraft within 7,490 kilometers (4,654 miles) above the surface during time of closest approach.

While this latest close approach places Cassini more than 6,400 kilometers (3,970 miles) higher above Titan's surface than the Jan. 12 flyby, it should not considered of lesser scientific value. Instead, this high-altitude encounter will provide an opportunity for some of the spacecraft's instruments to gain another unique perspective on this crepuscular world.

Monday, January 25, 2010

First of Many Asteroid Finds

The red dot at the center of this image is the first near-Earth asteroid discovered by NASA's Wide-Field Infrared Survey Explorer, or WISE -- an all-sky mapping infrared mission designed to see all sorts of cosmic objects.

Near-Earth objects are asteroids and comets with orbits that come close to Earth's path around the sun. This particular asteroid, called 2010 AB78, is roughly one kilometer (0.6 miles) in diameter, and is currently about 158 million kilometers (98 million miles) away from Earth. Its elliptical-shaped orbit takes it out beyond Mars and back in about as close to the sun as Earth. Because the asteroid's orbit is tilted relative to the plane of our solar system, astronomers do not think it poses a hazard to our planet. As with all near-Earth objects, 2010 AB78 will continue to be monitored.

The image shows three infrared wavelengths, with red representing the longest wavelength of 12 microns, and green and blue showing 4.6- and 3.4-micron light, respectively. The asteroid appears redder than the rest of the background stars because it is cooler and emits most of its light at longer infrared wavelengths. In visible light, this space rock is very faint and difficult to see.

WISE, which began its all-sky survey on Jan. 14, 2010, is expected to find about one hundred thousand previously undiscovered asteroids in the Main Belt between Mars and Jupiter, and hundreds of new near-Earth asteroids. It will also spot millions of new stars and galaxies.

Thursday, January 21, 2010

Rover Gives NASA an "Opportunity" to View Interior of Mars

NASA's Mars Exploration Rover Opportunity examined a rock called "Marquette Island" from mid-November 2009 until mid-January 2010. Studies of texture and composition suggest that this rock, not much bigger than a basketball, originated deep inside the Martian crust. A crater-digging impact could have excavated the rock and thrown it a long distance, to where Opportunity found it along the rover's long trek across the Meridiani plain toward Endeavour Crater.

This approximately true-color view of Marquette Island comes from combining three exposures that Opportunity's panoramic camera (Pancam) took through different filters during the rover's 2,117th Martian day, or sol, on Mars (Jan. 6, 2010). On the preceding sol, Opportunity's rock abrasion tool brushed dust out of the circular area where that tool had ground into the rock on sols 2100 and 2103 (Dec. 20 and 23, 2009). The dark circle left by the rock abrasion tool's work is approximately 5 centimeters (2 inches) in diameter.

Second Warmest Year on Record; End of Warmest Decade

2009 was tied for the second warmest year in the modern record, a new NASA analysis of global surface temperature shows. The analysis, conducted by the Goddard Institute for Space Studies (GISS) in New York City, also shows that in the Southern Hemisphere, 2009 was the warmest year since modern records began in 1880.

Although 2008 was the coolest year of the decade -- due to strong cooling of the tropical Pacific Ocean -- 2009 saw a return to near-record global temperatures. The past year was only a fraction of a degree cooler than 2005, the warmest year on record, and tied with a cluster of other years --1998, 2002, 2003, 2006 and 2007 1998 and 2007 -- as the second warmest year since recordkeeping began.

“There’s always an interest in the annual temperature numbers and on a given year’s ranking, but usually that misses the point,” said James Hansen, the director of GISS. “There's substantial year-to-year variability of global temperature caused by the tropical El Niño-La Niña cycle. But when we average temperature over five or ten years to minimize that variability, we find that global warming is continuing unabated."

Monday, January 18, 2010

Endeavour's STS-130 Mission

Commander George Zamka will lead the STS-130 mission to the International Space Station aboard space shuttle Endeavour. Terry Virts will serve as the pilot. Mission Specialists are Nicholas Patrick, Robert Behnken, Stephen Robinson and Kathryn Hire. Virts will be making his first trip to space.

Shuttle Endeavour and its crew will deliver to the space station a third connecting module, the Italian-built Tranquility node and the seven-windowed cupola, which will be used as a control room for robotics. The mission will feature three spacewalks.

Liftoff from NASA's Kennedy Space Center in Florida is targeted for February 7, 2010, at 4:39 a.m. EST

Tuesday, January 12, 2010

Solar Scientists Use 'Magnetic Mirror Effect' to Reproduce IBEX Observation

Ever since NASA's Interstellar Boundary Explorer, or IBEX, mission scientists released the first comprehensive sky map of our solar system's edge in particles, solar physicists have been busy revising their models to account for the discovery of a narrow "ribbon" of bright emission that was completely unexpected and not predicted by any model at the time.

Further study by a team of scientists funded through NASA's Heliophysics Guest Investigator program has produced a revised model that explains and closely reproduces the IBEX result by incorporating a single new effect into an existing model. The new effect, put forward by the IBEX team soon after sighting of the ribbon, is that the magnetic field surrounding our solar system—called the local galactic magnetic field—acts like a mirror for the particles that IBEX sees.

Tuesday, January 05, 2010

Sun Glints Seen from Space Signal Oceans and Lakes

In two new videos from NASA’s Deep Impact spacecraft, bright flashes of light known as sun glints act as beacons signaling large bodies of water on Earth. These observations give scientists a way to pick out planets beyond our solar system (extrasolar planets) that are likely to have expanses of liquid, and so stand a better chance of having life.

These sun glints are like sunshine glancing off the hood of a car. We can see them reflecting off a smooth surface when we are positioned in just the right way with respect to the sun and the smooth surface. On a planetary scale, only liquids and ice can form a surface smooth enough to produce the effect—land masses are too rough—and the surface must be very large. To stand out against a background of other radiation from a planet, the reflected light must be very bright. We won’t necessarily see glints from every distant planet that has liquids or ice.

“But these sun glints are important because, if we saw an extrasolar planet which had glints that popped up periodically, we would know that we were seeing lakes, oceans or other large bodies of liquid, such as water,” says Drake Deming, of NASA’s Goddard Space Flight Center in Greenbelt, Md. Deming is the deputy principal investigator who leads the team that works on the Extrasolar Planet Observations and Characterization (EPOCh) part of Deep Impact’s extended mission, called EPOXI. “And if we found large bodies of water on a distant planet, we would become much more optimistic about finding life.”

One of EPOCh’s goals is to observe the Earth from far away—in this case, about 11 million miles away—so that we know what an Earth-like planet would look like when viewed from our spacecraft. The images in these videos were collected when the spacecraft was close enough to resolve some of Earth’s features, but at the same time, Earth could be treated as a very distant, single point. “This allows us to properly simulate what we would have observed if Earth were an extrasolar planet,” says Michael A’Hearn, principal investigator for EPOXI.

Monday, January 04, 2010

Massive Black Hole Implicated in Stellar Destruction

New results from NASA's Chandra X-ray Observatory and the Magellan telescopes suggest that a dense stellar remnant has been ripped apart by a black hole a thousand times as massive as the Sun. If confirmed, this discovery would be a cosmic double play: it would be strong evidence for an intermediate mass black hole, which has been a hotly debated topic, and would mark the first time such a black hole has been caught tearing a star apart.

This scenario is based on Chandra observations, which revealed an unusually luminous source of X-rays in a dense cluster of old stars, and optical observations that showed a peculiar mix of elements associated with the X-ray emission. Taken together, a case can be made that the X-ray emission is produced by debris from a disrupted white dwarf star that is heated as it falls towards a massive black hole. The optical emission comes from debris further out that is illuminated by these X-rays.

The intensity of the X-ray emission places the source in the "ultraluminous X-ray source" or ULX category, meaning that it is more luminous than any known stellar X-ray source, but less luminous than the bright X-ray sources (active galactic nuclei) associated with supermassive black holes in the nuclei of galaxies. The nature of ULXs is a mystery, but one suggestion is that some ULXs are black holes with masses between about a hundred and several thousand times that of the Sun, a range intermediate between stellar-mass black holes and supermassive black holes located in the nuclei of galaxies.

Saturday, January 02, 2010

GOES-K, later renamed GOES-10

NOAA anticipated the end of GOES-10 several months ahead of time, and began deactivating GOES-10 on December 1 when it fired the spacecraft’s thrusters moving the satellite into a higher orbit above the Earth. On December 2, NOAA finished its third and final, firing putting it safely out of commission and put it in an unused drift orbit.

GOES-10 was originally planned for a five-year mission when it was launched in April 1997. It was positioned as NOAA’s GOES-West satellite, more than 22,000 miles above the Earth’s surface. In 2006 a newer satellite, GOES-11, replaced GOES-10. NOAA then repositioned GOES-10 to support hurricane forecasting efforts in South America. NOAA anticipates moving GOES-12 to provide coverage for South America by May 2010.

"GOES-10 has served America – and other nations – admirably and well beyond its expected lifespan," said Mary Kicza, assistant administrator for NOAA’s Satellite and Information Service. "The success of GOES-10, built by Space Systems/Loral, was a credit to a large team of NOAA staff, who acquired and managed the spacecraft and processed and distributed the data to users." Kicza added that with the help of its partners, including NASA, "NOAA is creating better satellites that will provide better data that improve our understanding – and prediction – of climate and weather."