vendredi 23 septembre 2011

UARS Re-Entry Expected Late Tonight, Early Saturday












NASA - Upper Atmosphere Research Satellite (UARS) Mission patch.

Sat, 24 Sep 2011

NASA's Upper Atmosphere Research Satellite, is expected to re-enter Earth's atmosphere expected late Friday, Sept. 23, or early Saturday, Sept. 24 (EDT). The risk to public safety or property is extremely small; safety is NASA's top priority.

As of 7 p.m. EDT on Sept. 23, 2011, the orbit of UARS was 90 miles by 95 miles (145 km by 150 km). Re-entry is expected between 11 p.m. Friday, Sept. 23, and 3 a.m., Sept. 24, Eastern Daylight Time (3 a.m. to 7 a.m. GMT). During that time period, the satellite will be passing over Canada, Africa and Australia, as well as vast areas of the Pacific, Atlantic and Indian oceans.

video
NASA UARS Satellite Reentry  

NASA's Upper Atmosphere Research Satellite, or UARS, is expected to re-enter Earth's atmosphere late Sept. 23 or early Sept. 24 Eastern Daylight Time, almost six years after the end of a productive scientific life. Although the spacecraft will break into pieces during re-entry, not all of it will burn up in the atmosphere.

The risk to public safety or property is extremely small, and safety is NASA's top priority. Since the beginning of the Space Age in the late-1950s, there have been no confirmed reports of an injury resulting from re-entering space objects. Nor is there a record of significant property damage resulting from a satellite re-entry.

It is still too early to say exactly when UARS will re-enter and what geographic area may be affected, but NASA is watching the satellite closely and will keep you informed. Visit this page for updates on the satellite's orbital track and predicted re-entry date.

› Re-Entry and Risk Assessment (498 KB PDF): http://www.nasa.gov/pdf/585584main_UARS_Status.pdf

› Frequently Asked Questions: Orbital Debris: http://www.nasa.gov/news/debris_faq.html

The updates posted here come from the Joint Space Operations Center of U.S. Strategic Command at Vandenberg Air Force Base, Calif., which works around the clock detecting, identifying and tracking all man-made objects in Earth orbit, including space junk.

The actual time of re-entry is difficult to predict because it depends on solar flux and the spacecraft's orientation as its orbit decays. As re-entry draws closer, predictions on the date will become more reliable.

Upper Atmosphere Research Satellite

Because the satellite's orbit is inclined 57 degrees to the equator, any surviving components of UARS will land within a zone between 57 degrees north latitude and 57 degrees south latitude. It is impossible to pinpoint just where in that zone the debris will land, but NASA estimates the debris footprint will be about 500 miles long.

If you find something you think may be a piece of UARS, do not touch it. Contact a local law enforcement official for assistance.

For more information about UARS, visit: http://www.nasa.gov/uars

Images, Video, Text, Credit: NASA / AGI.

Greetings, Orbiter.ch

Around the world – 50 000 times







ESA - ENVISAT Mission logo.

23 September 2011

ESA’s Envisat observation satellite yesterday completed its 50 000th circuit of Earth – travelling 2.25 billion km since its launch nearly a decade ago.

Envisat orbits our planet every 100 minutes, speeding along at more than seven kilometres per second.

During this milestone spin around the world on 22 September, the satellite passed from the Arctic to the Antarctic, catching glimpses of northern Greenland and New Zealand.

New Zealand

Launched on 28 February 2002, the lorry-sized Envisat is the largest Earth observation satellite ever built.

It is also the world’s most complex environmental satellite, with ten different instruments studying Earth’s land, oceans and atmosphere.

 Artist's impression of Envisat

They include the Medium Resolution Imaging Spectrometer, which captures images of ocean colour and land cover, like the above scene of New Zealand.

Greenland

The Advanced Synthetic Aperture Radar can be used day or night because it can see through clouds and darkness. This is particularly useful over polar regions, which are prone to long periods of bad weather and extended darkness.

Trace gases in the troposphere and stratosphere are measured globally by the Sciamachy imaging spectrometer, yielding maps of air pollution such as carbon dioxide, methane and nitrogen dioxide.

Nitrogen dioxide over China

Nitrogen dioxide – a mainly man-made gas – can cause lung damage and respiratory problems.

It also plays an important role in atmospheric chemistry because it leads to the production of ozone in the troposphere, the lowest part of the atmosphere.

Antarctic ozone hole

Envisat’s Michelson Interferometer for Passive Atmospheric Sounding monitors gases and pollutants. As one of three atmospheric instruments, it can map the levels of more than 20 trace gases, including ozone, as well as the pollutants that attack ozone.

The sensor is particularly useful for tracking the ozone hole over the Antarctic.

Mediterranean Sea

Other Envisat instruments include the Radar Altimeter, which measures surface height to an accuracy of a few centimetres, and the Advanced Along-Track Scanning Radiometer, which records global ground and sea-surface temperatures.

Related links:

Envisat Mission: http://envisat.esa.int/

Envisat images: http://www.esa.int/esa-mmg/mmg.pl?mission=Envisat&type=I

Envisat Earth Monitoring Live: http://envisat.esa.int/live/

Where is Envisat now?: http://envisat.esa.int/webcam/where_is_envisat.htm

MIRAVI: Earth live: http://miravi.eo.esa.int/en/

Images, Animation, Text, Credits: European Space Agency (ESA).

Best regards, Orbiter.ch

OPERA experiment invites scrutiny of unexpected results












CERN - European Organization for Nuclear Research logo.

23 Sep 2011


The OPERA experiment, which observes a neutrino beam from CERN 730 km away at Italy’s INFN Gran Sasso Laboratory, will present new results in a seminar at CERN today.

The OPERA result is based on the observation of over 15000 neutrino events measured at Gran Sasso, and appears to indicate that the neutrinos travel at a velocity 20 parts per million above the speed of light, nature’s cosmic speed limit. Given the potential far-reaching consequences of such a result, independent measurements are needed before the effect can either be refuted or firmly established. This is why the OPERA collaboration has decided to open the result to broader scrutiny.


Image above: A view of the OPERA detector in Gran Sasso, Italy. Neutrino beams from CERN in Switzerland are sent over 700km through the Earth's crust to the laboratory in Italy.

In order to perform this study, the OPERA Collaboration teamed up with experts in metrology from CERN and other institutions to perform a series of high precision measurements of the distance between the source and the detector, and of the neutrinos’ time of flight. The distance between the origin of the neutrino beam and OPERA was measured with an uncertainty of 20 cm over the 730 km travel path. The neutrinos’ time of flight was determined with an accuracy of less than 10 nanoseconds by using sophisticated instruments including advanced GPS systems and atomic clocks. The time response of all elements of the CNGS beam line and of the OPERA detector has also been measured with great precision.


"We have established synchronization between CERN and Gran Sasso that gives us nanosecond accuracy, and we’ve measured the distance between the two sites to 20 centimetres,” said Dario Autiero, the CNRS researcher who will give this afternoon’s seminar. “Although our measurements have low systematic uncertainty and high statistical accuracy, and we place great confidence in our results, we’re looking forward to comparing them with those from other experiments."

OPERA experiment site in Italy

“The potential impact on science is too large to draw immediate conclusions or attempt physics interpretations. My first reaction is that the neutrino is still surprising us with its mysteries.” said Ereditato. “Today’s seminar is intended to invite scrutiny from the broader particle physics community.”


The OPERA experiment was inaugurated in 2006, with the main goal of studying the rare transformation (oscillation) of muon neutrinos into tau neutrinos. One first such event was observed in 2010, proving the unique ability of the experiment in the detection of the elusive signal of tau neutrinos.

The OPERA1 experiment, which observes a neutrino beam from CERN2 730 km away at Italy’s INFN Gran Sasso Laboratory, will present new results in a seminar at CERN this afternoon at 16:00 CEST. The seminar will be webcast at http://webcast.cern.ch. Journalists wishing to ask questions may do so via twitter using the hash tag #nuquestions, or via the usual CERN press office channels.

More information:

Press release: OPERA experiment reports anomaly in flight time of neutrinos from CERN to Gran Sasso: http://press.web.cern.ch/press/PressReleases/Releases2011/PR19.11E.html

The OPERA collaboration's result is available on the preprint server arxiv.org: http://arxiv.org/abs/1109.4897

Quantum Diaries: Elementary, my dear neutrino: http://www.quantumdiaries.org/2011/09/23/elementary-my-dear-neutrino/

Images, Text, Credit: CERN / INFN / OPERA.

Greetings, Orbiter.ch

jeudi 22 septembre 2011

Aquarius Yields NASA'S First Global Map Of Ocean Salinity












NASA - Aquarius / SAC-D Mission patch.

Sep. 22, 2011

NASA's new Aquarius instrument has produced its first global map of the salinity of the ocean surface, providing an early glimpse of the mission's anticipated discoveries.

Aquarius, which is aboard the Aquarius/SAC-D (Satelite de Aplicaciones Científicas) observatory, is making NASA's first space observations of ocean surface salinity variations - a key component of Earth's climate. Salinity changes are linked to the cycling of freshwater around the planet and influence ocean circulation.


"Aquarius' salinity data are showing much higher quality than we expected to see this early in the mission," said Aquarius principal investigator Gary Lagerloef of Earth & Space Research in Seattle. "Aquarius soon will allow scientists to explore the connections between global rainfall, ocean currents and climate variations."

The new map, which shows a tapestry of salinity patterns, demonstrates Aquarius' ability to detect large-scale salinity distribution features clearly and with sharp contrast. The map is a composite of the data since Aquarius became operational on Aug. 25. The mission was launched June 10 from Vandenberg Air Force Base in California. Aquarius/SAC-D is collaboration between NASA and Argentina's space agency, Comision Nacional de Actividades Espaciales (CONAE).

"Aquarius/SAC-D already is advancing our understanding of ocean surface salinity and Earth's water cycle," said Michael Freilich, director of NASA's Earth Science Division at agency headquarters in Washington. "Aquarius is making continuous, consistent, global measurements of ocean salinity, including measurements from places we have never sampled before."

To produce the map, Aquarius scientists compared the early data with ocean surface salinity reference data. Although the early data contain some uncertainties, and months of additional calibration and validation work remain, scientists are impressed by the data's quality.

"Aquarius has exposed a pattern of ocean surface salinity that is rich in variability across a wide range of scales," said Aquarius science team member Arnold Gordon, professor of oceanography at Columbia University in New York and at Lamont-Doherty Earth Observatory of Columbia University in Palisades, N.Y. "This is a great moment in the history of oceanography. The first image raises many questions that oceanographers will be challenged to explain."

The map shows several well-known ocean salinity features such as higher salinity in the subtropics; higher average salinity in the Atlantic Ocean compared to the Pacific and Indian Oceans; and lower salinity in rainy belts near the equator, in the northernmost Pacific Ocean and elsewhere. These features are related to large-scale patterns of rainfall and evaporation over the ocean, river outflow and ocean circulation. Aquarius will monitor how these features change and study their link to climate and weather variations.

Aquarius satellite

Other important regional features are evident, including a sharp contrast between the arid, high-salinity Arabian Sea west of the Indian subcontinent, and the low-salinity Bay of Bengal to the east, which is dominated by the Ganges River and south Asia monsoon rains. The data also show important smaller details, such as a larger-than-expected extent of low-salinity water associated with outflow from the Amazon River.

Aquarius was built by NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., and the Goddard Space Flight Center in Greenbelt, Md., for NASA's Earth Systems Science Pathfinder Program. JPL is managing Aquarius through its commissioning phase and will archive mission data. Goddard will manage Aquarius mission operations and process science data. CONAE provided the SAC-D spacecraft and the mission operations center.

The new map is available at: http://photojournal.jpl.nasa.gov/catalog/PIA14786

For more information about Aquarius/SAC-D, visit: http://www.nasa.gov/aquarius  and http://www.conae.gov.ar/eng/principal.html

Images, Text, Credit: NASA / JPL / Goddard Space Flight Center.

Cheers, Orbiter.ch

Exploring an asteroid with the Desert RATS










NASA - "Desert" RATS patch.

22 September 2011

Earlier this month, European scientists linked up with astronauts roaming over the surface of an asteroid. Desert RATS, NASA’s realistic simulation of a future mission, this year included a European dimension for the first time.

It was not really an asteroid, but a desert near Flagstaff in Arizona, USA. Since 1999, scientists, astronauts and engineers from various NASA establishments and universities have gathered once a year to simulate human missions to the Moon and Mars.

One of two vehicles used in Desert RATS

Desert RATS – Desert Research and Technology Studies – have tested rovers, habitats, spacesuits, instruments, robots, communication systems, research methods and other technical, scientific and operational aspects of future missions.

These realistic ‘missions’ in extreme environments help to guide planning for future space exploration and build valuable experience in complex operations.

Fly me to an asteroid

This time, the crew of astronauts and geologists ‘landed’ on a nearby asteroid and ventured out on field trips – by foot and on two Space Exploration Vehicles.

Desert RATS field trip by an astronaut and geologist

For two weeks, the crew lived in a Deep Space Habitat with realistic radio links to their mother craft and mission control on Earth.

They had to cope with a two-way communications delay of 100 seconds with Earth, and limited bandwidth.

Reproducing the low gravity on an asteroid was impossible, but the ‘spacewalkers’ acted as though they were on a small body.

For instance, they had to attach themselves to the ground when they used their hammers to take geological samples – otherwise, the recoil would have sent them spinning into space.

Europe comes aboard

In last year’s DRATS, William Carey, an ESA specialist in future exploration operations strategies, was the only European in Arizona but this year a full science team was active in Europe.


Image above: Multimedia library of the Erasmus centre at ESTEC served as a base for European Desert RATS 'science backroom'.

“The simulation is similar to a cricket game: long periods of inactivity punctuated by periods of intense concentration,” explained William, referring to the long preparations.

“When the extravehicular activities began, everyone’s hearts started to beat faster.”

This was especially so in the two ‘science backrooms’, each with a team of scientists and engineers supporting one vehicle and its crew. The European scientists worked in the Erasmus backroom at ESA’s ESTEC technical centre in Noordwijk, the Netherlands which normally support science operations for the ISS.

Happy team of the ESTEC 'science backroom'

The team of 11 from Italy, France, the Netherlands, ESA and NASA communicated with the crews out in Arizona, just like a backroom would on a real asteroid mission.

“These scientists were the backup eyes and the extra brain power of the crew,” said Sylvie Espinasse, coordinator for the undertaking in ESA.

“Operating with access to real-time audio and video feeds, we could monitor astronauts and geologists in the field and communicate with them taking into account the delay.”

During the two intense days when ESTEC was online, the team tracked everything on the asteroid surface, observing what the crew was doing, trying to make geological sense of it and helping the explorers to squeeze all they could from the limited spacewalking time.

Goro Komatsu

“I enjoyed this different type of exploration tremendously,” said Goro Komatsu, a field geologist from the International Research School of Planetary Science, Italy.

He was excited when the action was interrupted during the second day by a thunderstorm: “It was very useful to learn how to face the unexpected!”

After all, on a real mission to an asteroid, there might be solar storms, hampering communications and forcing the astronauts to protect themselves.

Related links:

Desert RATS (NASA): http://www.nasa.gov/exploration/analogs/desertrats/index.html

Institut des Sciences de la Terre d'Orléans (CNRS, France): http://www.isto.cnrs-orleans.fr/

International Research School of Planetary Science (Pescara, Italy): http://www.irsps.unich.it/

Department of Petrology, Vrije Universiteit (Amsterdam, the Netherlands): http://www.falw.vu.nl/en/research/earth-sciences/petrology/index.asp

Images, Text, Credits: ESA / NASA  / F. Didot / C. Dekker / J. Myrrhe.

Greetings, Orbiter.ch

mercredi 21 septembre 2011

Liftoff of Ariane 5 with Arabsat-5C & SES-2


















Arianespace Flight VA 204 - Ariane 5 ECA – Arabsat 5C – SES-2 poster.


September 21, 2011

Ariane Flight VA204

Arianespace’s mission with a dual-satellite payload of Arabsat-5C and SES-2 is now underway following the fifth liftoff of an Ariane 5 from Europe’s Spaceport in 2011.

video
Liftoff of Ariane 5 with Arabsat-5C & SES-2

Total lift performance for today’s launch is approximately 8,975 kg., with the spacecraft to be deployed during a flight lasting 35 minutes.

SES-2 will be utilized by European satellite telecommunications operator SES, and was manufactured by Orbital Sciences Corporation of the U.S.  Carrying 24 C-band and 24 Ku-band transponders, the satellite is to generate approximately five kilowatts of payload power, and will replace SES’ AMC-3 spacecraft at 87 deg. West for coverage over North America and the Caribbean.

SES-2 satellite
The SES-2 platform also is equipped with the Commercially Hosted Infrared Payload (CHIRP) sensor for the U.S. Air Force – which integrates a wide-field of view sensor.

Arabsat-5C satellite

Arabsat-5C is a multi-mission spacecraft for the Arab Satellite Communications Organization (Arabsat), designed to deliver capacity in both the C- and Ka-bands for a range of communications services.  It was manufactured in a joint effort by Europe’s EADS Astrium and Thales Alenia Space, and will be located at Arabsat’s 20 deg. East orbital position.

Related links:

EADS Astrium: http://www.astrium.eads.net/

Arabsat: http://www.arabsat.com/

SES: http://www.ses.com/

Thales Alenia Space: http://www.thalesgroup.com/Markets/Space/Home

Orbital Sciences Corporation: http://www.orbital.com/

Images, Video, Text, Credits: ARIANESPACE / Thales Alenia Space / EADS Astrium.

Greetings, Orbiter.ch

An Angry Bird in the Sky












ESO - European Southern Observatory logo.

21 September 2011

New ESO image of the Lambda Centauri Nebula

The Running Chicken Nebula

A new image from the Wide Field Imager on the MPG/ESO 2.2-metre telescope reveals the Lambda Centauri Nebula, a cloud of glowing hydrogen and newborn stars in the constellation of Centaurus (The Centaur). The nebula, also known as IC 2944, is sometimes nicknamed the Running Chicken Nebula, from a bird-like shape some people see in its brightest region.

In the nebula, which lies around 6500 light-years from Earth, hot newborn stars that formed from clouds of hydrogen gas shine brightly with ultraviolet light. This intense radiation in turn excites the surrounding hydrogen cloud, making it glow a distinctive shade of red. This red shade is typical of star-forming regions, another famous example being the Lagoon Nebula (eso0936).

Some people see a chicken shape in pictures of this red star-forming region, giving the nebula its nickname — though there is some disagreement over exactly which part of the nebula is chicken shaped, with various bird-like features in evidence across the picture [1].
The Running Chicken Nebula in the constellation of Centaurus

Aside from the glowing gas, another sign of star formation in IC 2944 is the series of opaque black clumps silhouetted against the red background in part of this image. These are examples of a type of object called Bok globules. They appear dark as they absorb the light from the luminous background. However, observations of these dark clouds using infrared telescopes, which are able to see through the dust that normally blocks visible light, have revealed that stars are forming within many of them.

The most prominent collection of Bok globules in this image is known as Thackeray’s Globules, after the South African astronomer who discovered them in the 1950s. Visible among a group of bright stars in the upper right part of the image, these globules feature in a famous image taken by the NASA/ESA Hubble Space Telescope (link).

video
Zooming in on the Running Chicken Nebula

While Hubble offers greater detail in its image of this small area, the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory captures a much larger panorama in its images, covering an area of sky roughly the size of the full Moon [2]. Much like a zoom lens on a camera lets a photographer choose the most appropriate field of view when taking a picture, the dramatically different viewpoints offered by different telescopes can offer complementary data to scientists studying astronomical objects which cover an extended area of the sky.

If the stars cocooned in Thackeray’s Globules are still gestating, then the stars of cluster IC 2948, embedded within the nebula, are their older siblings. Still young in stellar terms, at just a few million years old, these stars shine brightly, and their ultraviolet radiation provides much of the energy that lights up the nebula. These glowing nebulae are relatively short-lived in astronomical terms (typically a few million years), meaning that the Lambda Centauri Nebula will eventually fade away as it loses both its gas and its supply of ultraviolet radiation.

Notes:

[1] Ideas for where the chicken outline lies on the picture can be submitted through the Your ESO Pictures Flickr group for a chance to win some interesting prizes.

[2] This image was produced as part of the ESO Cosmic Gems programme. This is a new initiative to produce images of interesting, intriguing or visually attractive objects using ESO telescopes, for the purposes of education and public outreach. The programme makes use of small amounts of observing time, combined with otherwise unused time on the telescopes’ schedules so as to minimise the impact on science observations. All data collected are also made available to astronomers through ESO’s science archive.

More information:

ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links:

    Hubble Space Telescope closeup of Thackeray’s Globules in the Running Chicken Nebula:    http://www.spacetelescope.org/images/opo0201a/

    ESO Cosmic Gems page: http://www.eso.org/public/outreach/gems.html

Images, Text, Credits: ESO / IAU and Sky & Telescope / Richard Hook / Video: ESO / N. Risinger (skysurvey.org) / Music: John Dyson (from the album Moonwind).

Greetings, Orbiter.ch

mardi 20 septembre 2011

NASA'S WISE Mission Captures Black Hole's Wildly Flaring Jet









NASA - WISE Mission patch.

Sept. 20, 2011

Astronomers using NASA's Wide-field Infrared Survey Explorer (WISE) have captured rare data of a flaring black hole, revealing new details about these powerful objects and their blazing jets.

Scientists study jets to learn more about the extreme environments around black holes. Much has been learned about the material feeding black holes, called accretion disks, and the jets themselves through studies using X-rays, gamma rays and radio waves. But key measurements of the brightest part of the jets, located at their bases, have been difficult despite decades of work. WISE is offering a new window into this missing link through its infrared observations.


This artist's concept illustrates what the flaring black hole called GX 339-4 might look like. Image credit: NASA.

"Imagine what it would be like if our sun were to undergo sudden, random bursts, becoming three times brighter in a matter of hours, and then fading back again. That's the kind of fury we observed in this jet," said Poshak Gandhi, a scientist with the Japan Aerospace Exploration Agency (JAXA). He is lead author of a new study on the results appearing in the Astrophysical Journal Letters. "With WISE's infrared vision, we were able to zoom in on the inner regions near the base of the stellar-mass black hole's jet for the first time and the physics of jets in action."

The black hole, called GX 339-4, had been observed previously. It lies more than 20,000 light-years away from Earth near the center of our galaxy. It has a mass at least six times greater than the sun. Like other black holes, it is an ultra-dense collection of matter, with gravity that is so great even light cannot escape. In this case, the black hole is orbited by a companion star that feeds it. Most of the material from the companion star is pulled into the black hole, but some of it is blasted away as a jet flowing at nearly the speed of light.

"To see bright flaring activity from a black hole you need to be looking at the right place at the right time," said Peter Eisenhardt, the project scientist for WISE at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "WISE snapped sensitive infrared pictures every 11 seconds for a year, covering the whole sky, allowing it to catch this rare event."

Observing the jet's variability was possible because of images taken of the same patch of sky over time, a feature of NEOWISE, the asteroid-hunting portion of the WISE mission. WISE data enabled the team to zoom in on the very compact region around the base of the jet streaming from the black hole. The size of the region is equivalent to the width of a dime seen at the distance of our sun.

The results surprised the team, showing huge and erratic fluctuations in the jet activity on timescales ranging from 11 seconds to a few hours. The observations are like a dance of infrared colors and show the size of the jet's base varies. Its radius is approximately 15,000 miles (24,140 kilometers) with dramatic changes by as large as a factor of 10 or more.


WISE images showing strong bursts and dimming of infrared light in the black hole GX 339-4. The data cover a period of approximately 1 day, speeded up. Infrared light has a wavelength about 15 times longer than the eye can see. Animation made by Poshak Gandhi (JAXA) using WISE images.

"If you think of the black hole's jet as a firehose, then it's as if we've discovered the flow is intermittent and the hose itself is varying wildly in size," Poshak said.

The new data also allowed astronomers to make the best measurements yet of the black hole's magnetic field, which is 30,000 times more powerful than the one generated by Earth at its surface. Such a strong field is required for accelerating and channeling the flow of matter into a narrow jet. The WISE data are bringing astronomers closer than ever to understanding how this exotic phenomenon works.

JPL manages and operated WISE for NASA's Science Mission Directorate in Washington. The spacecraft was put into hibernation mode after it scanned the sky twice, completing its main objectives. The mission was selected under NASA's Explorers Program, which is managed by the agency's Goddard Space Flight Center in Greenbelt, Md.

The science instrument was built by the Space Dynamics Laboratory in Logan, Utah; and the spacecraft was built by Ball Aerospace and Technologies Corp., in Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena.

Related links:

Image gallery: http://www.nasa.gov/mission_pages/WISE/multimedia/gallery/gallery-index.html

Solar system safari: http://www.nasa.gov/mission_pages/WISE/multimedia/gallery/neowise/gallery-index.html

For more WISE information,visit: http://www.nasa.gov/wise, http://wise.astro.ucla.edu and http://jpl.nasa.gov/wise

Images (mentioned), Text, Credits: NASA / Jet Propulsion Laboratory / Whitney Clavin / Trent J. Perrotto.

Best regards, Orbiter.ch

China to Launch Space Station Test Module Next Week








CNSA - China National Space Administration logo.

Sept. 20, 2011

China will launch a test module for its first space station next week between Sept. 27 and Sept. 30, state media reported today (Sept. 20).

The unmanned module, called Tiangong-1 (which means "Heavenly Palace") will test autonomous docking procedures and other space operations in preparation for China's plan to build a 60-ton space station by the year 2020.

The Chinese Long March 2F rocket set to launch Tiangong-1 has already been rolled out to its launch platform at the Jiuquan Satellite Launch Center in northwest China's Gansu Province, according to state-run news service Xinhua.


Image above: China is developing its first full-fledged space station, called Tiangong (Heavenly Palace). Early tests of China’s skills at rendezvous and docking, shown in this artist's illustration, are set to begin in 2011.
Credit: China Manned Space Engineering Office.

The liftoff was delayed last month when a Long March 2C booster, similar to the rocket that will loft Tiangong-1, failed to deliver an experimental unmanned satellite to orbit. However, after an investigation into the accident, China successfully launched a military satellite aboard a related Long March 3B/E rocket on Sunday (Sept. 18), clearing the way for the Tiangong liftoff.

Long March 2F rocket

Final tests of the spacecraft and its booster will take place over the next few days, a project spokesperson told Xinhua.

"Every main system is standing by and the final preparations are running smoothly," Xinhua reported.

The 8.5-ton Tiangong-1 is slated to dock with the unmanned Shenzhou 8 spacecraft, which will launch at a later date. It will be the first docking between Chinese spacecraft, and will represent a significant step forward in the nation's space capabilities, experts have said. Medical and engineering experiments will also be carried aboard Tiangong-1.


China is only the third country, after the Soviet Union and the United States, to launch a person to orbit. The first Chinese manned mission, Shenzhou 5, launched astronaut Yang Liwei in 2003. Two more manned missions followed, including a flight that featured the nation's first spacewalk in 2008.

Images, Text, Credits: CNSA / Space.com / Clara Moskowitz / China Daily.

Greetings, Orbiter.ch

lundi 19 septembre 2011

NASA's Wise Raises Doubt About Asteroid Family Believed Responsible for Dinosaur Extinction







NASA - WISE Mission logo.

Sept. 19, 2011

Observations from NASA's Wide-field Infrared Survey Explorer (WISE) mission indicate the family of asteroids some believed was responsible for the demise of the dinosaurs is not likely the culprit, keeping the case open on one of Earth's greatest mysteries.

While scientists are confident a large asteroid crashed into Earth approximately 65 million years ago, leading to the extinction of dinosaurs and some other lifeforms on our planet, they do not know exactly where the asteroid came from or how it made its way to Earth. A 2007 study using visible-light data from ground-based telescopes first suggested the remnant of a huge asteroid, known as Baptistina, as a possible suspect.

According to that theory, Baptistina crashed into another asteroid in the main belt between Mars and Jupiter about 160 million years ago. The collision sent shattered pieces as big as mountains flying. One of those pieces was believed to have impacted Earth, causing the dinosaurs' extinction.

Since this scenario was first proposed, evidence developed that the so-called Baptistina family of asteroids was not the responsible party. With the new infrared observations from WISE, astronomers say Baptistina may finally be ruled out.

This artist's concept shows a broken-up asteroid. Image credit: NASA / JPL-Caltech

"As a result of the WISE science team's investigation, the demise of the dinosaurs remains in the cold case files," said Lindley Johnson, program executive for the Near Earth Object (NEO) Observation Program at NASA Headquarters in Washington. "The original calculations with visible light estimated the size and reflectivity of the Baptistina family members, leading to estimates of their age, but we now know those estimates were off. With infrared light, WISE was able to get a more accurate estimate, which throws the timing of the Baptistina theory into question."

WISE surveyed the entire celestial sky twice in infrared light from January 2010 to February 2011. The asteroid-hunting portion of the mission, called NEOWISE, used the data to catalogue more than 157,000 asteroids in the main belt and discovered more than 33,000 new ones.

Visible light reflects off an asteroid. Without knowing how reflective the surface of the asteroid is, it's hard to accurately establish size. Infrared observations allow a more accurate size estimate. They detect infrared light coming from the asteroid itself, which is related to the body's temperature and size. Once the size is known, the object's reflectivity can be re-calculated by combining infrared with visible-light data.

The NEOWISE team measured the reflectivity and the size of about 120,000 asteroids in the main belt, including 1,056 members of the Baptistina family. The scientists calculated the original parent Baptistina asteroid actually broke up closer to 80 million years ago, half as long as originally proposed.

This calculation was possible because the size and reflectivity of the asteroid family members indicate how much time would have been required to reach their current locations -- larger asteroids would not disperse in their orbits as fast as smaller ones. The results revealed a chunk of the original Baptistina asteroid needed to hit Earth in less time than previously believed, in just about 15 million years, to cause the extinction of the dinosaurs.

"This doesn't give the remnants from the collision very much time to move into a resonance spot, and get flung down to Earth 65 million years ago," said Amy Mainzer, a study co-author and the principal investigator of NEOWISE at NASA's Jet Propulsion Laboratory (JPL) in Pasadena. Calif. "This process is thought to normally take many tens of millions of years." Resonances are areas in the main belt where gravity nudges from Jupiter and Saturn can act like a pinball machine to fling asteroids out of the main belt and into the region near Earth.

The asteroid family that produced the dinosaur-killing asteroid remains at large. Evidence that a 10-kilometer asteroid impacted Earth 65 million years ago includes a huge, crater-shaped structure in the Gulf of Mexico and rare minerals in the fossil record, which are common in meteorites but seldom found in Earth's crust. In addition to the Baptistina results, the NEOWISE study shows various main belt asteroid families have similar reflective properties. The team hopes to use NEOWISE data to disentangle families that overlap and trace their histories.

"We are working on creating an asteroid family tree of sorts," said Joseph Masiero, the lead author of the study. "We are starting to refine our picture of how the asteroids in the main belt smashed together and mixed up."

JPL manages and operated WISE for NASA's Science Mission Directorate. The spacecraft was put into hibernation mode after it scanned the entire sky twice, completing its main objectives. The principal investigator, astronomer Edward Wright, is at UCLA.

The mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan.

The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

For more information about WISE, visit: http://www.nasa.gov/wise

NEOWISE image gallery: http://www.nasa.gov/mission_pages/WISE/multimedia/gallery/neowise/gallery-index.html

Image, Text, Credit: NASA / JPL-Caltech.

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