Posted on by Fraser Cain

Cassini’s Feeling Fine

Image credit: NASA

NASA’s Cassini spacecraft continues to hurtle towards its distant rendezvous with the planet Saturn in July 1, 2004. Controllers had the spacecraft take some test photographs of a star, and the camera haze that showed up earlier in the mission appears to be clearing up, as they had hoped it would. The most recent communication with the spacecraft by the Goldstone tracking station last week indicated that Cassini is in excellent health and working normally.

NASA’s Cassini spacecraft continues to fly in good health, speeding toward a July 1, 2004, appointment to begin orbiting Saturn.

Test images of a star taken last week provide strong encouragement that a haze problem noticed on a Cassini camera lens is clearing up as anticipated, said Robert Mitchell, Cassini-Huygens program manager at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

A 60-day period of warming the spacecraft’s narrow-angle camera to a temperature just above freezing ended May 1. Heaters were built into the camera in anticipation of potential lens hazing; warming treatments have corrected similar hazing on other spacecraft.

Cassini’s narrow-angle camera performed flawlessly for the spacecraft’s December 2000 flyby of Jupiter. The haze first appeared last year, during the cruise between Jupiter and Saturn. Warming the camera to 4 degrees Celsius (39 degrees Fahrenheit) for eight days ending in January 2002 produced improvements, so the same heating was repeated for 60 days.

The new test images of the bright star Spica show that, by one measure, at least 90 percent of the image diffusion originally caused by the lens haze has been corrected. The improvement may actually be greater, because the new images were taken at a temperature warmer than the camera’s optimal operating temperature of about minus 90 C (minus 130 F). Another warming treatment, to last 26 days, began May 9.

About six months after Cassini begins orbiting Saturn, it will release its piggybacked Huygens probe for descent through the thick atmosphere of the moon Titan on Jan. 14, 2005. Cassini-Huygens is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Office of Space Science, Washington, D.C. Additional information about Cassini-Huygens is available online at: http://saturn.jpl.nasa.gov .

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Eleven More Jupiter Moons Discovered

Image credit: NASA

Jupiter pushed past the other planets with the recent discovery of 11 new moons, bringing its total to 39. A team of US astronomers discovered the additional satellites (all 2-4 kilometres in diameter) using one of the world’s most powerful telescopes: the Canada-France-Hawaii 3.6 metre. Digital images of the space around Jupiter were processed using computers to detect objects moving in orbit, and to reject passing asteroids.

The discovery of 11 small moons orbiting Jupiter leapfrogs the number of that planet’s moons to 39, nine more than the record of the previous champ, Saturn.

A team led by astronomers from the University of Hawaii, Honolulu, made the discovery based on images taken in December 2001 and later follow-up observations. Orbits were determined by collaborators at NASA’s Jet Propulsion Laboratory, in Pasadena, Calif., and the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.

Researchers estimate the new-found natural satellites are each about two to four kilometers (one to two miles) in diameter, and were probably passing rocks captured by Jupiter’s gravity long ago.

The discovery-team leaders, Scott Sheppard and Dr. David Jewitt of the University of Hawaii, also discovered 11 other small satellites of Jupiter in 2000.

The new moons were discovered by Sheppard, Jewitt and Jan Kleyna of Cambridge University, England. They used the Canada-France-Hawaii 3.6-meter (142-inch) telescope with one of the largest digital imaging cameras in the world to obtain sensitive images of a wide area around Jupiter.

The digital images were processed and searched using computers. Candidate satellites were monitored in the succeeding months at the University of Hawaii’s 2.2-meter (88-inch) telescope to confirm their orbits and to reject asteroids masquerading as satellites.

JPL’s Dr. Robert Jacobson and Harvard-Smithsonian’s Dr. Brian Marsden determined the satellites’ irregular — highly elongated and tilted — orbits. All 11 objects orbit in the direction opposite to the rotation of the planet.

The orbits of the irregular satellites strongly suggest an origin by capture. Since no efficient contemporary capture mechanisms are known, it is likely that the irregular satellites were acquired when Jupiter was young, possibly still in the process of condensing down to its equilibrium size. As yet, nothing is known about their surface properties, compositions or densities, but they are presumed to be rocky objects like the asteroids.

The new discoveries bring the known total of Jovian satellites to 39, of which 31 are irregulars. The eight regular satellites include four large moons discovered by the astronomer Galileo Galilei and four smaller moons on circular orbits closer to Jupiter. Jupiter’s nearest rival for having the largest number of known satellites is Saturn, with 30, of which 13 are irregular.

The satellites were formally announced by the International Astronomical Union on Circular No. 7900 (May 16, 2002). More information about them is available online from the University of Hawaii at http://www.ifa.hawaii.edu/~sheppard/satellites/jup.html. Other information about the Jupiter system is available from JPL at http://www.jpl.nasa.gov/solar_system/planets/jupiter_index.html.

The Institute for Astronomy at the University of Hawaii conducts research into galaxies, cosmology, stars, planets and the Sun. The Canada-France-Hawaii telescope is funded by the University of Hawaii and the governments of Canada and France. JPL, a division of the California Institute of Technology, Pasadena, is NASA’s lead center for robotic exploration of the solar system.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Oxygen System Working Again

The crew of the International Space Station successfully repaired the malfunctioning oxygen system over the weekend. The system was malfunctioning over the course of last week, so it was brought offline so the crew could make repairs. Life support equipment was shut down again on Sunday for three hours – NASA engineers believe it was because of bad computer data – but everything was brought online again on Monday. Station residents weren’t in any danger during either problem.

Posted on by Fraser Cain

Could 1 in 3 Earth-like Worlds Have Life?

Two researchers from Australia believe that life in the Universe may be more common than previously thought. Since life only took half a billion years to gain a foothold on our planet, they theorize, the odds of it happening on any Earth-like world must be good. With only one planet to sample, though, the Earth, there still isn’t any way to judge whether our planet is an anomaly or well within the norm. NASA’s upcoming Terrestrial Planet Finder due for launch in a decade will help scan for Earth-like planets in the future.

Posted on by Fraser Cain

Chinese Rocket Launches Two Satellites

A Chinese Long March 4B rocket successfully placed to satellites into orbit on Wednesday: a Fengyun-1D meteorological satellite and a Haiyang-1 marine surveying satellite. Both satellites were developed in China and will help the country’s efforts to monitor its weather. This is the country’s second launch of the year.

Posted on by Fraser Cain

Station Oxygen Generator Breaks

Astronauts on board the International Space Station are working to repair a malfunctioning oxygen generator. The primary oxygen has been working off and on over the past few days, so the crew has switched to their backup solid-fuel canisters to keep the atmosphere breathable. NASA doesn’t feel that there’s any urgency to the situation, and hopes to have the problem fixed shortly. Even if they don’t get it working quickly, the space shuttle Endeavour will launch on May 30 with additional oxygen supplies.

Posted on by Fraser Cain

Hubble Views Wispy Nebula

Image credit: Hubble

A new photograph taken by the Hubble Space Telescope shows a nebula formed around a group of young, hot, stars. Designated N44C, the nebula is located in the Large Magellanic Cloud, a nearby, small companion galaxy to the Milky Way. It’s peculiar because the star located at the centre of the nebula is inexplicably hot – it could be that the star has a black hole or neutron star companion.

Resembling the hair in Botticelli’s famous portrait of the birth of Venus, softly glowing filaments stream from a complex of hot young stars. This image of a nebula, known as N44C, comes from the archives of NASA’s Hubble Space Telescope (HST). It was taken with the Wide Field Planetary Camera 2 in 1996 and is being presented by the Hubble Heritage Project.

N44C is the designation for a region of glowing hydrogen gas surrounding an association of young stars in the Large Magellanic Cloud, a nearby, small companion galaxy to the Milky Way visible from the Southern Hemisphere.

N44C is peculiar because the star mainly responsible for illuminating the nebula is unusually hot. The most massive stars, ranging from 10-50 times more massive than the Sun, have maximum temperatures of 54,000 to 90,000 degrees Fahrenheit (30,000 to 50,000 degrees Kelvin). The star illuminating N44C appears to be significantly hotter, with a temperature of about 135,000 degrees Fahrenheit (75,000 degrees Kelvin)!

Ideas proposed to explain this unusually high temperature include the possibility of a neutron star or black hole that intermittently produces X-rays but is now “switched off.”

On the top right of this Hubble image is a network of nebulous filaments that inspired comparison to Botticelli. The filaments surround a Wolf-Rayet star, another kind of rare star characterized by an exceptionally vigorous “wind” of charged particles. The shock of the wind colliding with the surrounding gas causes the gas to glow.

N44C is part of the larger N44 complex, which includes young, hot, massive stars, nebulae, and a “superbubble” blown out by multiple supernova explosions. Part of the superbubble is seen in red at the very bottom left of the HST image.

The data were taken in November 1996 with Hubble’s Wide Field Planetary Camera 2 by Donald Garnett (University of Arizona) and collaborators and stored in the Hubble archive. The image was composed by the Hubble Heritage Team (STScI/AURA).

Original Source: Hubble News Release

Posted on by Fraser Cain

Buzz Aldrin Working on Mars Shuttle Plans

Although he was the second human to walk on the moon, astronaut Buzz Aldrin isn’t getting out the space race yet. He’s working on plans to develop a massive shuttle that would travel between the Earth and Mars, transferring people and supplies to and from the Red Planet. The shuttle wouldn’t actually stop at Mars, it would just drop off people and then use gravity to make a return voyage back to Earth to pick up more people. And although the idea sounds way off, Aldrin, and researchers from Purdue University believe something could be developed by 2018.

Posted on by Fraser Cain

Cannibalistic Stars May Hold Clues to the Big Bang

Image credit: PPARC

A team of UK astronomers have discovered a new class of cannibalistic stars that may explain one of the mysteries surrounding the Big Bang. These stars formed shortly after the Big Bang but don’t contain any lithium -which astronomers predicted should be there. Astronomers believed that they must have misunderstood some essential aspect about the early universe, but this new research helps explain what happened to the lithium; it was destroyed by the star’s interaction with a partner star.

A team of UK astronomers announced this month the discovery of cannibalistic stars that explain one of the mysteries surrounding the Big Bang. The stars are almost as old as the Universe and they reveal what space was like in the very beginning.

The team from the Open University found that a group of 14-billion-year-old stars were all in a spin (literally) because of a nasty phase earlier in their lives. They were, in short, cannibalistic stars. The scientists’ discovery not only explains the origin of these mysterious stars, but also strengthens the Big Bang theory. The Big Bang is the name given to the rapid expansion of the Universe that marked the beginning of space and time; it explains the origin of the matter in the universe – including the matter which people are made of.

The stars under investigation are some of the oldest in the Universe. They formed out of gas clouds not long after the Big Bang. The OU team, led by Dr Sean Ryan, found that some of the stars that formed early in the life of the Universe were very unusual. They contained none of the metal lithium which astronomers believe is produced in the Big Bang.

Dr Ryan said:

“Observations showed that about 1 star in 20 contained no lithium, and some astronomers were concerned that this might mean we had misunderstood something important about the Big Bang and the origin of the Universe.”

New and more detailed observations of the peculiar stars were made with the 4.2-metre-diameter William Herschel Telescope. Using high precision equipment, the team found that most of the stars without lithium were spinning very fast. “Measuring the spin speed of stars is very difficult,” said Dr Ryan, “this is why no-one had seen this before. Most 14-billion-year-old stars do not spin very fast at all but these ones had up to 16 times as much spin energy as the Sun, our nearest star. We knew that the extra energy could come from only one source; another star.”

Dr Ulrich Kolb, an OU astronomer who specialises in interacting stars, explained what happened. “When these stars formed out of the gas clouds, not just one but two stars formed very near one another. Fatally, they were too close together for their own good. As they grew older, the smaller one captured the outer layers of the larger one. Very little now remains of what was the larger star; it has been cannibalised by its companion.”

The material captured by the companion carried orbital energy that was converted into spin energy. It was the discovery of the excessive spin energy that revealed the history of the objects.

The scientists believe that the lithium was destroyed in nuclear reactions shortly before the star-eating episode occurred.

Dr Ryan said:

“It’s rather a relief that we have discovered why the lithium-depleted stars are so different to most others. Knowing that the Big Bang theory tells us correctly how much lithium was produced gives us confidence that we really do understand much about the origin of the entire universe. Hydrogen that was formed in the Big Bang powers the Sun, which in turn provides energy to the Earth. It is also a vital component of pure water, which is so essential to life. Also we now know more about what happens when stars feed on one another.”

Using a technique called Doppler spectroscopy, the observations were made by measuring the speeds at which the stars are moving. This is similar to the way traffic speeds are measured on roads, but with stars clocking up many kilometres per second, not just a few kilometres per hour. The William Herschel Telescope on which the observations were made is one of the UK’s major telescopes. It is co-funded and operated by the Particle Physics and Astronomy Council (PPARC). It is located under the clear skies of the Canary Islands, where observing conditions are much better than in Great Britain. The telescope is shared with Dutch and Spanish astronomers. Dr Sean Ryan will be observing from the Canary Islands on 22-24 May.

Original Source: PPARC News Release

Posted on by Fraser Cain

NASA Selects Two Planet Finding Concepts

Image credit: NASA

NASA has selected two new concepts to advance the search for extrasolar planets; one of the technologies will eventually be selected for the Terrestrial Planet Finder mission. The first choice involves the use of an Infrared Interferometer, where multiple spacecraft will simulate a much larger observatory and search for the infrared signature of a planet around a distant star. The other concept is a Visible Light Coronagraph; a telescope 4 times as large and 10 times as powerful as Hubble, capable of imaging distant planets directly. NASA will choose one path in 2005-2006.

As part of its quest to find Earth-sized planets around stars and look for telltale chemical signatures of life, NASA has chosen two mission architecture concepts for further study and technology development.

The two architectures are being explored for the Terrestrial Planet Finder mission. Each would use a different means to achieve the same goal ? to block the light from a parent star in order to see its much smaller, dimmer planets. That technology challenge has been likened to finding a firefly near the beam of a brilliant searchlight from far away. Additional goals of the mission would include characterizing the surfaces and atmospheres of newfound planets, and looking for the chemical signatures of life.

The two candidate architectures are:

— Infrared Interferometer: Multiple small telescopes on a fixed structure or on separated spacecraft flying in precision formation would simulate a much larger, very powerful telescope. The interferometer would utilize a technique called nulling to reduce the starlight by a factor of one million, thus enabling the detection of the very dim infrared emission from the planets.

— Visible Light Coronagraph: A large optical telescope, with a mirror three to four times bigger and at least 10 times more precise than the Hubble Space Telescope, would collect starlight and the very dim reflected light from the planets. The telescope would have special optics to reduce the starlight by a factor of one billion, thus enabling astronomers to detect the faint planets.

The Terrestrial Planet Finder project at NASA?s Jet Propulsion Laboratory, Pasadena, Calif., selected the two candidates based on results from four industrial-academic teams that conducted a 2-1/2 year study of more than 60 possible designs. The two architectures were determined to be sufficiently realistic to warrant further study and technological development in support of a launch of Terrestrial Planet Finder by the middle of the next decade.

NASA and JPL will issue calls for proposals seeking input on the development and demonstration of technologies to implement the two architectures, and on scientific research relevant to planet finding. It is anticipated that one of the two architectures will be selected in 2005 or 2006 to be implemented for the mission, which may include international collaboration.

Terrestrial Planet Finder is part of NASA?s Origins Program, a series of missions to study the formation of galaxies, stars and planets, and to search for life. The program seeks to answers the questions: Where did we come from? Are we alone?

More information on the Terrestrial Planet Finder is available at http://tpf.jpl.nasa.gov/ .

More information on the Origins Program is available at http://origins.jpl.nasa.gov . Additional information on JPL?s planet-finding missions is available at http://planetquest.jpl.nasa.gov/ .

JPL manages the Terrestrial Planet Finder mission and the Origins Program for NASA’s Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.

Original Source: NASA News Release