vendredi 29 mars 2013

NASA's Swift Sizes Up Comet ISON












NASA - Swift Mission patch.

March 29, 2013

Astronomers from the University of Maryland at College Park (UMCP) and Lowell Observatory have used NASA's Swift satellite to check out comet C/2012 S1 (ISON), which may become one of the most dazzling in decades when it rounds the sun later this year.

Using images acquired over the last two months from Swift's Ultraviolet/Optical Telescope (UVOT), the team has made initial estimates of the comet's water and dust production and used them to infer the size of its icy nucleus.

"Comet ISON has the potential to be among the brightest comets of the last 50 years, which gives us a rare opportunity to observe its changes in great detail and over an extended period," said Lead Investigator Dennis Bodewits, an astronomer at UMCP.

video
Comet ISON's Path Through the Solar System

Video above: Comet ISON is now approaching the inner solar system. Discovered last year, the comet remains unusually active for its distance from the sun. If current trends continue, ISON could rank as one of the brightest comets in decades when it makes its close approach to the sun in late November. This animation shows the comet's approach and departure from the inner solar system from various perspectives. Credit: NASA's Goddard Space Flight Center Scientific Visualization Studio.

Additional factors, including an encounter with Mars followed by a scorching close approach to the sun, make comet ISON an object of special interest. In late February, at NASA's request, a team of comet experts initiated the Comet ISON Observing Campaign (CIOC) to assist ground- and space-based facilities in obtaining the most scientifically useful data.

Like all comets, ISON is a clump of frozen gases mixed with dust. Often described as "dirty snowballs," comets emit gas and dust whenever they venture near enough to the sun that the icy material transforms from a solid to gas, a process called sublimation. Jets powered by sublimating ice also release dust, which reflects sunlight and brightens the comet.

Typically, a comet's water content remains frozen until it comes within about three times Earth's distance to the sun. While Swift's UVOT cannot detect water directly, the molecule quickly breaks into hydrogen atoms and hydroxyl (OH) molecules when exposed to ultraviolet sunlight. The UVOT detects light emitted by hydroxyl and other important molecular fragments as well as sunlight reflected from dust.


Image above: The Ultraviolet/Optical Telescope aboard NASA's Swift imaged comet ISON (center) on Jan. 30, when it was located about 3.3 degrees from the bright star Castor in the constellation Gemini. At the time of this 5.5-minute optical exposure, ISON was about 5,000 times fainter than the limit of human vision. Credit: NASA/Swift/D. Bodewits, UMCP.

The Jan. 30 UVOT observations reveal that ISON was shedding about 112,000 pounds (51,000 kg) of dust, or about two-thirds the mass of an unfueled space shuttle, every minute. By contrast, the comet was producing only about 130 pounds (60 kg) of water every minute, or about four times the amount flowing out of a residential sprinkler system.

"The mismatch we detect between the amount of dust and water produced tells us that ISON's water sublimation is not yet powering its jets because the comet is still too far from the sun," Bodewits said. "Other more volatile materials, such as carbon dioxide or carbon monoxide ice, evaporate at greater distances and are now fueling ISON's activity."

At the time, the comet was 375 million miles (604 million km) from Earth and 460 million miles (740 million km) from the sun. ISON was at magnitude 15.7 on the astronomical brightness scale, or about 5,000 times fainter that the threshold of human vision.

Similar levels of activity were observed in February, and the team plans additional UVOT observations.

While the water and dust production rates are relatively uncertain because of the comet's faintness, they can be used to estimate the size of ISON's icy body. Comparing the amount of gas needed for a normal comet to blow off dust at the rate observed for ISON, the scientists estimate that the nucleus is roughly 3 miles (5 km) across, a typical size for a comet. This assumes that only the fraction of the surface most directly exposed to the sun, about 10 percent of the total, is actively producing jets.

An important question is whether ISON will continue to brighten at the same pace once water evaporation becomes the dominant source for its jets. Will the comet sizzle or fizzle?

"It looks promising, but that's all we can say for sure now," said Matthew Knight, an astronomer at Lowell Observatory in Flagstaff, Ariz., and a member of the Swift and CIOC teams. "Past comets have failed to live up to expectations once they reached the inner solar system, and only observations over the next few months will improve our knowledge of how ISON will perform."

(Click on the image for enlarge)

Image above: From now through October, comet ISON tracks through the constellations Gemini, Cancer and Leo as it falls toward the sun. Credit: NASA's Goddard Space Flight Center/Axel Mellinger.

Based on ISON's orbit, astronomers think the comet is making its first-ever trip through the inner solar system. Before beginning its long fall toward the sun, the comet resided in the Oort comet cloud, a vast shell of perhaps a trillion icy bodies that extends from the outer reaches of the planetary system to about a third of the distance to the star nearest the sun.

Formally designated C/2012 S1 (ISON), the comet was discovered on Sept. 21, 2012, by Russian astronomers Vitali Nevski and Artyom Novichonok using a telescope of the International Scientific Optical Network located near Kislovodsk.

The first of several intriguing observing opportunities occurs on Oct. 1, when the inbound comet passes about 6.7 million miles (10.8 million km) from Mars.

"During this close encounter, comet ISON may be observable to NASA and ESA spacecraft now working at Mars," said Michael Kelley, an astronomer at UMCP and also a Swift and CIOC team member. "Personally, I'm hoping we'll see a dramatic postcard image taken by NASA's latest Mars explorer, the Curiosity rover."

Fifty-eight days later, on Nov. 28, ISON will make a sweltering passage around the sun. The comet will approach within about 730,000 miles (1.2 million km) of its visible surface, which classifies ISON as a sungrazing comet. In late November, its icy material will furiously sublimate and release torrents of dust as the surface erodes under the sun's fierce heat, all as sun-monitoring satellites look on. Around this time, the comet may become bright enough to glimpse just by holding up a hand to block the sun's glare.

NASA's Swift satellite. Credit: NASA's Goddard Space Flight Center

Sungrazing comets often shed large fragments or even completely disrupt following close encounters with the sun, but for ISON neither fate is a forgone conclusion.

"We estimate that as much as 10 percent of the comet's diameter may erode away, but this probably won't devastate it," explained Knight. Nearly all of the energy reaching the comet acts to sublimate its ice, an evaporative process that cools the comet's surface and keeps it from reaching extreme temperatures despite its proximity to the sun.

Following ISON's solar encounter, the comet will depart the sun and move toward Earth, appearing in evening twilight through December. It will swing past Earth on Dec. 26, approaching within 39.9 million miles (64.2 million km) or about 167 times farther than the moon.

Whether we'll look back on ISON as a "comet of the century" or as an overhyped cosmic dud remains to be seen, but astronomers are planning to learn the most they can about this unusual visitor no matter what happens.

Related Links:

Download the video in HD formats and print-resolution images from NASA Goddard's Scientific Visualization Studio: http://svs.gsfc.nasa.gov/goto?11222

NASA's Comet ISON Observing Campaign: http://sungrazer.nrl.navy.mil/index.php?p=ison

"NASA's Deep Impact Spacecraft Eyes Comet ISON" (02.05.13): http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130205.html

Michael Kelley's blog: "Comet ISON is Coming": http://www.astro.umd.edu/~msk/blog/articles/comet-ison-jan13

Vitali Nevski and Artyom Novichonok: C/2012 S1 (ISON): http://www.cometchaser.de/discoverystories/Comet-discoverers.html#2012ISON

"NASA's Swift Monitors Departing Comet Garradd" (04.13.12): http://www.nasa.gov/mission_pages/swift/bursts/comet-garradd.html

Images (mentioned), Video (mentioned), Text, Credit: NASA's Goddard Space Flight Center / Francis Reddy.

Greetings, Orbiter.ch

New Crew Aboard Station After Express Flight










ISS - Expedition 35 Mission patch.

March 29, 2013

video
 New Crew on Station After Express Flight

The Soyuz TMA-08M spacecraft carrying three new Expedition 35 crew members docked with the International Space Station’s Poisk module at 10:28 p.m. EDT Thursday, completing its accelerated journey to the orbiting complex in less than six hours.

View video of docking:
http://www.nasa.gov/multimedia/videogallery/index.html?media_id=161382271

 Preparatives of the hatch opening. Image credits: NASA TV / Screen capture by Danielle Klomp

Soyuz Commander Pavel Vinogradov and Alexander Misurkin of the Russian Federal Space Agency (Roscosmos) and NASA astronaut Chris Cassidy, who launched from the Baikonur Cosmodrome in Kazakhstan at 4:43 p.m. (2:43 a.m. Friday, Baikonur time) are the first station crew members to take this expedited route to the orbiting laboratory. The Soyuz reached the station after only four orbits instead of the usual two-day launch-to-docking mission profile for a Russian spacecraft. While this is the first crewed spacecraft to employ this technique, Russian space officials successfully tested it with the last three Progress cargo vehicles.

Hatch opening. Image credits: NASA TV / Screen capture by Danielle Klomp

After the hatches opened at 12:35 a.m. Friday, Cassidy, Vinogradov and Misurkin joined Commander Chris Hadfield of the Canadian Space Agency and Flight Engineers Tom Marshburn of NASA and Roman Romanenko of Roscosmos who have been residing at the orbital laboratory since Dec. 21, 2012. All six crew members crew then participated in a welcome ceremony with family members and mission officials gathered at the Russian Mission Control Center in Star City near Moscow.

Hatch open. Image credits: NASA TV / Screen capture by Danielle Klomp

Expedition 35 will operate with its full six-person crew complement until May when Hadfield, Marshburn and Romanenko return to Earth aboard their Soyuz TMA-07M spacecraft. Their departure will mark the beginning of Expedition 36 under the command of Vinogradov, who along with crewmates Cassidy and Misurkin will maintain the station as a three-person crew until the launch of three additional flight engineers in late May. Cassidy, Vinogradov and Misurkin are scheduled to return to Earth in September.

Welcome ceremony. Image credits: NASA TV / Screen capture by Danielle Klomp

During the approximate six-month timeframe of Expeditions 35 and 36, 137 investigations will be performed on the U.S. operating segment of the station, and 44 on the Russian segment. More than 430 investigators from around the world are involved in the research. The investigations cover human research, biological and physical sciences, technology development, Earth observation, and education.

Read more about Expedition 35:
http://www.nasa.gov/mission_pages/station/expeditions/expedition35/index.html

For more information about the International Space Station (ISS), visit:
http://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Video, Text, Credits: NASA / NASA TV / Screen captures by Danielle Klomp (Roscosmos Fans Group member on Facebook) / Orbiter.ch Aerospace.

Greetings, Orbiter.ch

SolarImpulse ready to cross the USA








SolarImpulse 2013 Across America logo.

March 29, 2013

SolarImpulse is ready to cross the United States. The solar plane should leave San Francisco to New York on May 1.

The experimental Swiss aircraft SolarImpulse, powered by electric motors powered by solar energy, is ready to cross the United States from west to east. After several flights of preparation, Solar Impulse is expected to leave San Francisco to New York on May 1, said co-founder André Borschberg project.

Assembly of the aircraft completed, ready to fly

"We are now ready to fly across America," said co-founder of the project, Mr. Borschberg, during a press conference in Mountain View, California (west) in a shed next to the Solar Impulse .

However, the crossing will be five steps for security reasons, he said. He pointed out that the machine can technically do this nonstop but there can be only one pilot. It would take at least three days to cover the distance at 70 km / h, cruising speed of the aircraft of 1600 kg.

"We are constrained to fly up to 24 hours" each time, said André Borschberg, one of two pilots with Bertrand Piccard, initiator of the project and president of the firm. The first step is Phoenix (Arizona) and Dallas Fort Worth Texas and then either Atlanta (Georgia), Nashville (Tennessee) and St Louis (Missouri), he said.

SolarImpulse 2013 Across America (click on the image for enlarge)

The fourth stage will bring SolarImpulse Dulles Airport near Washington DC in mid-June and New York Kennedy Airport in early July, the final destination. The unit will remain between one week and ten days at each stage. The public, schoolchildren and students can see the plane and ask for pilots and other project participants.

Around the World in 2015

SolarImpulse, a project launched ten years ago, had its maiden flight in June 2009. In 2010, the solar aircraft whose wingspan is equivalent to a Boeing 747, was flown non-stop 26 hours. He had demonstrated its ability to accumulate enough electricity during the day to continue to fly at night.

SolarImpulse night flight

A year later, he made his first international flight between Belgium and France in June 2012, the first transcontinental journey of 2500 km between Madrid and Rabat, Morocco in 20 hours. Bertrand Piccard and André Borschberg planning a world tour in 2015 with an improved version of this device.

For more information about SolarImpulse, Visit: http://www.solarimpulse.com/

Images , Text, Credits: ATS / SolarImpulse / Translation: Orbiter.ch Aerospace.

Best regards, Orbiter.ch

jeudi 28 mars 2013

Soyuz TMA-08M Docks to International Space Station












ROSCOSMOS - Soyuz TMA-08M Mission patch.

March 28, 2013

Soyuz Completes Expedited Journey to Station

 

Images above: View of video monitor and display instruments and computers aboard Soyuz TMA-08M (ISS 600 meters distance).  Photo credit: NASA TV / Screen capture: Orbiter.ch Aerospace.

The Soyuz TMA-08M vehicle docked to the International Space Station at 10:28 p.m. EDT over the Pacific Ocean just west of Peru. Aboard the space station, Expedition 35 Commander Chris Hadfield of the Canadian Space Agency and Flight Engineers Tom Marshburn of NASA and Roman Romanenko of the Russian Federal Space Agency will welcome Soyuz crew members Chris Cassidy, Pavel Vinogradov and Alexander Misurkin when the hatches between the two spacecraft are opened.

video
Fast-Tracked Soyuz Docks to Station

The Soyuz TMA-08M spacecraft carrying three new Expedition 35 crew members docked with the International Space Station’s Poisk module at 10:32 p.m. EDT Thursday, completing an accelerated journey to the orbiting complex in less than six hours.


Image above: The Soyuz TMA-08M spacecraft approaches the International Space Station. Photo credit: NASA TV / Screen capture: Orbiter.ch Aerospace.

Soyuz Commander Pavel Vinogradov and Alexander Misurkin of the Russian Federal Space Agency (Roscosmos) and NASA astronaut Chris Cassidy, who launched from the Baikonur Cosmodrome in Kazakhstan at 4:43 p.m. EDT Thursday (2:43 a.m. Friday, Baikonur time) are the first station crew members to take this expedited route to the orbiting laboratory. The Soyuz reached the station after only four orbits instead of the usual two-day launch-to-docking mission profile for a Russian spacecraft. While this is the first crewed spacecraft to employ this technique, Russian space officials successfully tested it with the last three Progress cargo flights.

Soyuz TMA-08M Crew. Photo credit: ROSCOSMOS

After the hatches open at 12:10 a.m. Friday, Cassidy, Vinogradov and Misurkin will join Commander Chris Hadfield of the Canadian Space Agency and Flight Engineers Tom Marshburn of NASA and Roman Romanenko of Roscosmos who have been residing at the orbital laboratory since Dec. 21, 2012. All six crew members crew will then participate in a welcome ceremony with family members and mission officials gathered at the Russian Mission Control Center in Star City near Moscow.

Soyuz TMA-08M docked at ISS. Photo credit: NASA TV

NASA TV coverage of the hatch opening and welcome ceremony begins at 11:30 p.m. Watch NASA TV: http://www.nasa.gov/ntv

 
Image above: Soyuz TMA-M - A new series of the legendary Soyuz spacecrafts (description). Image credit: Rianovosti.

Expedition 35 will operate with its full six-person crew complement until May when Hadfield, Marshburn and Romanenko return to Earth aboard their Soyuz TMA-07M spacecraft. Their departure will mark the beginning of Expedition 36 under the command of Vinogradov, who along with crewmates Cassidy and Misurkin will maintain the station as a three-person crew until the launch of three additional flight engineers in late May. Cassidy, Vinogradov and Misurkin are scheduled to return to Earth in September.

Read more about Expedition 35: http://www.nasa.gov/mission_pages/station/expeditions/expedition35/index.html

For more information about the International Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Video, Text, Credits: ROSCOSMOS / ROSOSMOS TV / NASA / NASA TV / Orbiter.ch Aerospace / Rianovosti.

Greetings, Orbiter.ch

New Station Crew in Orbit, Docking Tonight












ROSCOSMOS - Soyuz TMA-08M Mission patch.

March 28, 2013

NASA's Chris Cassidy and Russian cosmonauts Pavel Vinogradov and Alexander Misurkin are now in orbit after launching from the Baikonur Cosmodrome in Kazakhstan.


Image aboove: The Soyuz TMA-08 spacecraft launches from the Baikonur Cosmodrome in Kazakhstan. Photo credit: NASA TV.

Cassidy, Vinogradov and Misurkin will dock their Soyuz capsule with the International Space Station at 10:31 p.m. EDT tonight, the first time a crew has docked to the station the same day they left Earth.

video
Soyuz Launches to Space Station 

Soyuz Commander Pavel Vinogradov and Alexander Misurkin of the Russian Federal Space Agency (Roscosmos) and NASA astronaut Chris Cassidy are the first station crew members to take this expedited route to the orbiting laboratory. They are scheduled to rendezvous and dock with the station after only four orbits instead of the standard two-day flight required to reach the complex. While this is the first crewed spacecraft to employ this technique, Russian space officials have successfully tested it with the last three Progress cargo flights.

Cassidy, Vinogradov and Misurkin will dock with the station’s Poisk module at 10:32 p.m. After the hatches open at 12:10 a.m. Friday, the new trio will join Commander Chris Hadfield of the Canadian Space Agency and Flight Engineers Tom Marshburn of NASA and Roman Romanenko of Roscosmos who have been residing at the orbital laboratory since Dec. 21, 2012. All six crew members crew will then participate in a welcome ceremony with family members and mission officials gathered at the Russian Mission Control Center in Star City near Moscow.

Interior view of Soyuz TMA-08M in flight

NASA TV coverage of the docking begins at 9:30 p.m. and returns at 11:30 for the hatch opening and welcome ceremony.

Expedition 35 will operate with its full six-person crew complement until May when Hadfield, Marshburn and Romanenko return to Earth aboard their Soyuz TMA-07M spacecraft. Their departure will mark the beginning of Expedition 36 under the command of Vinogradov, who along with crewmates Cassidy and Misurkin will maintain the station as a three-person crew until the launch of three additional flight engineers in late May. Cassidy, Vinogradov and Misurkin are scheduled to return to Earth in September.

During the approximate six-month timeframe of Expeditions 35 and 36, 137 investigations will be performed on the U.S. operating segment of the station, and 44 on the Russian segment. More than 430 investigators from around the world are involved in the research. The investigations cover human research, biological and physical sciences, technology development, Earth observation, and education.


Image above: Expedition 35 Chris Cassidy of NASA, along with Pavel Vinogradov and Alexander Misurkin of the Russian Federal Space Agency (Roscosmos). Photo credit: NASA/Victor Zelentsov.

Cassidy, a commander in the U.S. Navy, is making his second spaceflight. His first visit to the station was as an STS-127 mission specialist aboard space shuttle Endeavour in July 2009. During that mission Cassidy performed three spacewalks, spending more than 18 hours outside the orbiting complex.

This is the third space mission for Vinogradov, a former design engineer. Previously, Vinogradov was a crew member aboard space station Mir for 197 days in 1997-98 and spent 182 days aboard the International Space Station in 2006 as an Expedition 13 flight engineer.

A retired lieutenant colonel in the Russian Air Force, Misurkin will be making his first spaceflight. He was selected as a cosmonaut candidate in 2006 and qualified as a test-cosmonaut in 2009.

Read more about Expedition 35: http://www.nasa.gov/mission_pages/station/expeditions/expedition35/index.html

For more information about the International Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/index.html

Images, Video, Text, Credits: ROSCOSMOS / ROSCOSMOS TV / NASA TV / Orbiter.ch Aerospace.

Best regards, Orbiter.ch

Hubble observes the hidden depths of Messier 77












ESA - Hubble Space Telescope logo.

28 March 2013

 Hubble image of Messier 77

The NASA/ESA Hubble Space Telescope has captured this vivid image of spiral galaxy Messier 77, one of the most famous and well-studied galaxies in the sky. The patches of red across this image highlight pockets of star formation along the pinwheeling arms, with dark dust lanes stretching across the galaxy’s energetic centre.

Messier 77 is a galaxy in the constellation of Cetus, some 45 million light-years away from us. Also known as NGC 1068, it is one of the most famous and well-studied galaxies. It is a real star among galaxies, with more papers written about it than many other galaxies put together!

 Wide-field image of Messier 77 (ground-based image)

Despite its current fame and striking swirling appearance, the galaxy has been a victim of mistaken identity a couple of times; when it was initially discovered in 1780, the distinction between gas clouds and galaxies was not known, causing finder Pierre Méchain to miss its true nature and label it as a nebula. It was misclassified again when it was subsequently listed in the Messier Catalogue as a star cluster.

Now, however, it is firmly categorised as a barred spiral galaxy, with loosely wound arms and a relatively small central bulge. It is the closest and brightest example of a particular class of galaxies known as Seyfert galaxies — galaxies that are full of hot, highly ionised gas that glows brightly, emitting intense radiation.

video
  Zooming in on Messier 77

Strong radiation like this is known to come from the heart of Messier 77 — caused by a very active black hole that is around 15 million times the mass of our Sun. Material is dragged towards this black hole and circles around it, heating up and glowing strongly. This region of a galaxy alone, although comparatively small, can be tens of thousands of times brighter than a typical galaxy.

Although no competition for the intense centre, Messier 77’s spiral arms are also very bright regions. Dotted along each arm are knotty red clumps — a signal that new stars are forming. These baby stars shine strongly, ionising nearby gas which then glows a deep red colour as seen in the image above. The dust lanes stretching across this image appear as a rusty, brown-red colour due to a phenomenon known as reddening; the dust absorbs more blue light than red light, enhancing its apparent redness.

video
 Panning across Messier 77

A version of this image won second place in the Hubble’s Hidden Treasures Image Processing Competition, entered by contestant Andre van der Hoeven [1].

Notes:

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

[1] Hidden Treasures is an initiative to invite astronomy enthusiasts to search the Hubble archive for stunning images that have never been seen by the general public. The competition is now closed, and the list of winners, including André’s image of Messier 77, is available here.

Links:

    Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/

    Hubble’s Hidden Treasures: http://www.spacetelescope.org/projects/hiddentreasures/contest/

Images, Text, Credits: NASA / ESA & A. van der Hoeven / Digitized Sky Survey 2 / Videos: NASA, ESA, Digitized Sky Survey 2. Acknowledgement: A. van der Hoeven.

Greetings, Orbiter.ch

mercredi 27 mars 2013

Saturn is Like an Antiques Shop, Cassini Suggests












NASA / ESA - Cassini Mission to Saturn patch.

March 27, 2013

 Bright Moons

Image above: The Cassini spacecraft observes three of Saturn's moons set against the darkened night side of the planet. Image credit: NASA/JPL-Caltech/Space Science Institute.

A new analysis of data from NASA's Cassini spacecraft suggests that Saturn's moons and rings are gently worn vintage goods from around the time of our solar system's birth.

Though they are tinted on the surface from recent “pollution,” these bodies date back more than 4 billion years. They are from around the time that the planetary bodies in our neighborhood began to form out of the protoplanetary nebula, the cloud of material still orbiting the sun after its ignition as a star. The paper, led by Gianrico Filacchione, a Cassini participating scientist at Italy's National Institute for Astrophysics, Rome, has just been published online by the Astrophysical Journal.

"Studying the Saturnian system helps us understand the chemical and physical evolution of our entire solar system," said Filacchione. "We know now that understanding this evolution requires not just studying a single moon or ring, but piecing together the relationships intertwining these bodies."

Global View of Iapetus' Dichotomy

Image above: These two global images of Iapetus show the extreme brightness dichotomy on the surface of this peculiar Saturnian moon. Image credit: NASA/JPL-Caltech/Space Science Institute.

Data from Cassini's visual and infrared mapping spectrometer (VIMS) have revealed how water ice and also colors -- which are the signs of non-water and organic materials --are distributed throughout the Saturnian system. The spectrometer’s data in the visible part of the light spectrum show that coloring on the rings and moons generally is only skin-deep.

Using its infrared range, VIMS also detected abundant water ice – too much to have been deposited by comets or other recent means. So the authors deduce that the water ices must have formed around the time of the birth of the solar system, because Saturn orbits the sun beyond the so-called "snow line." Out beyond the snow line, in the outer solar system where Saturn resides, the environment is conducive to preserving water ice, like a deep freezer. Inside the solar system's "snow line," the environment is much closer to the sun's warm glow, and ices and other volatiles dissipate more easily.

The colored patina on the ring particles and moons roughly corresponds to their location in the Saturn system. For Saturn's inner ring particles and moons, water-ice spray from the geyser moon Enceladus has a whitewashing effect.

Affecting Two Rings

Image above: The effects of the small moon Prometheus loom large on two of Saturn's rings in this image taken a short time before Saturn's August 2009 equinox. Image credit: NASA/JPL-Caltech/Space Science Institute.

Farther out, the scientists found that the surfaces of Saturn's moons generally were redder the farther they orbited from Saturn. Phoebe, one of Saturn's outer moons and an object thought to originate in the far-off Kuiper Belt, seems to be shedding reddish dust that eventually rouges the surface of nearby moons, such as Hyperion and Iapetus.

A rain of meteoroids from outside the system appears to have turned some parts of the main ring system – notably the part of the main rings known as the B ring -- a subtle reddish hue. Scientists think the reddish color could be oxidized iron -- rust -- or polycyclic aromatic hydrocarbons, which could be progenitors of more complex organic molecules.

One of the big surprises from this research was the similar reddish coloring of the potato-shaped moon Prometheus and nearby ring particles. Other moons in the area were more whitish.

Cassini spacecraft. Image credit: NASA/JPL-Caltech

"The similar reddish tint suggests that Prometheus is constructed from material in Saturn's rings," said co-author Bonnie Buratti, a VIMS team member based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Scientists had been wondering whether ring particles could have stuck together to form moons -- since the dominant theory was that the rings basically came from satellites being broken up. The coloring gives us some solid proof that it can work the other way around, too."

"Observing the rings and moons with Cassini gives us an amazing bird's-eye view of the intricate processes at work in the Saturn system, and perhaps in the evolution of planetary systems as well," said Linda Spilker, Cassini project scientist, based at JPL. "What an object looks like and how it evolves depends a lot on location, location, location."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The visual and infrared mapping spectrometer team is based at the University of Arizona, Tucson.

For more information about the Cassini-Huygens mission visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov and http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Images (mentioned), Text, Credits: NASA / JPL / Jia-Rui Cook.

Cheers, Orbiter.ch

Hunting High-Mass Stars With Herschel












ESA - Herschel Mission patch.

27 March 2013

 W3

In this new view of a vast star-forming cloud called W3, ESA’s Herschel space observatory tells the story of how massive stars are born.

W3 is a giant molecular cloud containing an enormous stellar nursery, some 6200 light-years away in the Perseus Arm, one of our Milky Way Galaxy’s main spiral arms.

Spanning almost 200 light-years, W3 is one of the largest star-formation complexes in the outer Milky Way, hosting the formation of both low- and high-mass stars. The distinction is drawn at eight times the mass of our own Sun: above this limit, stars end their lives as supernovas.

Dense, bright blue knots of hot dust marking massive star formation dominate the upper left of the image in the two youngest regions in the scene: W3 Main and W3 (OH). Intense radiation streaming away from the stellar infants heats up the surrounding dust and gas, making it shine brightly in Herschel’s infrared-sensitive eyes.

Older high-mass stars are also seen to be heating up dust in their environments, appearing as the blue regions labelled AFGL 333 in the lower left of the annotated version of the image, and the loop of KR 140, at bottom right.

W3 annotated

Extensive networks of much colder gas and dust weave through the scene in the form of red filaments and pillar-like structures. Several of these cold cores conceal low-mass star formation, hinted at by tiny yellow knots of emission.

By studying the two regions of massive star formation – W3 Main and W3 (OH) – scientists have made progress in solving one of the major conundrums in the birth of massive stars. That is, even during their formation, the radiation blasting away from these stars is so powerful that they should push away the very material they are feeding from. If this is the case, how can massive stars form at all?

Observations of W3 point toward a possible solution: in these very dense regions, there appears to be a continuous process by which the raw material is moved around, compressed and confined, under the influence of clusters of young, massive protostars.

Herschel spacecraft, the ESA's giant infrared observatory

Through their strong radiation and powerful winds, populations of young high-mass stars may well be able to build and maintain localised clumps of material from which they can continue to feed during their earliest and most chaotic years, despite their incredible energy output.

Related links:

Herschel: ESA's giant infrared observatory: http://www.esa.int/Our_Activities/Space_Science/Herschel

Herschel postcard gallery: http://archives.esac.esa.int/hsa/aio/doc/postcardGallery.html

The Milky Way Project: http://www.milkywayproject.org/

Herschel overview: http://www.esa.int/Our_Activities/Space_Science/Herschel

Online Showcase of Herschel Images OSHI: http://oshi.esa.int/

Herschel operations: http://www.esa.int/Our_Activities/Operations/Herschel_operations

Herschel in depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=16

Herschel Science Centre: http://herschel.esac.esa.int/

Images, Text, Credits: ESA / PACS & SPIRE consortia, A. Rivera-Ingraham & P.G. Martin, Univ. Toronto, HOBYS Key Programme (F. Motte).

Best regards, Orbiter.ch

Young, Hot and Blue












ESO - European Southern Observatory logo.

27 March 2013

Stars in the cluster NGC 2547

Young stars in the open star cluster NGC 2547

This pretty sprinkling of bright blue stars is the cluster NGC 2547, a group of recently formed stars in the southern constellation of Vela (The Sail). This image was taken using the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile.

The Universe is an old neighbourhood — roughly 13.8 billion years old. Our galaxy, the Milky Way, is also ancient — some of its stars are more than 13 billion years old (eso0425*). Nevertheless, there is still a lot of action: new objects form and others are destroyed. In this image, you can see some of the newcomers, the young stars forming the cluster NGC 2547.

The open star cluster NGC 2547 in the constellation of Vela

But, how young are these cosmic youngsters really? Although their exact ages remain uncertain, astronomers estimate that NGC 2547’s stars range from 20 to 35 million years old. That doesn't sound all that young, after all. However, our Sun is 4600 million years old and has not yet reached middle age. That means that if you imagine that the Sun as a 40 year-old person, the bright stars in the picture are three-month-old babies.

Most stars do not form in isolation, but in rich clusters with sizes ranging from several tens to several thousands of stars. While NGC 2547 contains many hot stars that glow bright blue, a telltale sign of their youth, you can also find one or two yellow or red stars which have already evolved to become red giants. Open star clusters like this usually only have comparatively short lives, of the order of several hundred million years, before they disintegrate as their component stars drift apart.

Wide-field view of the open star cluster NGC 2547

Clusters are key objects for astronomers studying how stars evolve through their lives. The members of a cluster were all born from the same material at about the same time, making it easier to determine the effects of other stellar properties.

The star cluster NGC 2547 lies in the southern constellation of Vela (The Sail), about 1500 light-years from Earth, and is bright enough to be easily seen using binoculars. It was discovered in 1751 by the French astronomer Nicolas-Louis de Lacaille during an astronomical expedition to the Cape of Good Hope in South Africa, using a tiny telescope of less than two centimetres aperture.

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Zooming into the open star cluster NGC 2547

Between the bright stars in this picture you can see plenty of other objects, especially when zooming in. Many are fainter or more distant stars in the Milky Way, but some, appearing as fuzzy extended objects, are galaxies, located millions of light-years beyond the stars in the field of view.

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A close look at the young stars in the open star cluster NGC 2547

More information:

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. 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 the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

*eso0425: http://www.eso.org/public/news/eso0425/

Images, Text, Credits: ESO / Richard Hook / IAU and Sky & Telescope / Digitized Sky Survey 2. Acknowledgement: Davide De Martin / Videos: ESO/Nick Risinger (skysurvey.org) Music: movetwo.

For more information about the European Southern Observatory (ESO), visit: http://www.eso.org/public/

Greetings, Orbiter.ch

mardi 26 mars 2013

MAVEN Mars Magnetometer






NASA - MAVEN Mission logo labeled.

March 26, 2013

MAVEN spacecraft in orbit around Mars

When you navigate with a compass you can orient yourself thanks to Earth’s global magnetic field. But on Mars, if you were to walk around with a compass it would haphazardly point from one anomaly to another, because the Red Planet does not possess a global magnetosphere. Scientists think that this lack of a protective magnetic field may have allowed the solar wind to strip away the Martian atmosphere over billions of years, and now NASA’s MAVEN spacecraft will study this process in detail with its pair of ring core fluxgate magnetometers.

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MAVEN Magnetometer

MAVEN’s dual magnetometers will allow scientists to study the interaction between the solar wind and the Martian atmosphere, giving us a better understanding of how Mars has evolved from a warm, wet climate to the cold, arid one we see today.

For more information about MAVEN mission, visit: http://science.nasa.gov/missions/maven/

NASA - Mars Atmosphere and Volatile EvolutioN (MAVEN) mission: http://www.nasa.gov/mission_pages/maven/main/index.html

Image, Video, Text, Credit: NASA's Goddard Space Flight Center.

Best regards, Orbiter.ch

Curiosity Resumes Science Investigations












NASA - Mars Science Laboratory (MSL) patch.

March 26, 2013


This view of Curiosity's left-front and left-center wheels and of marks made by wheels on the ground in the "Yellowknife Bay" area comes from one of six cameras used on Mars for the first time more than six months after the rover landed. Image credit: NASA/JPL-Caltech.

NASA's Mars rover Curiosity has resumed science investigations after recovery from a computer glitch that prompted the engineers to switch the rover to a redundant main computer on Feb. 28.

The rover has been monitoring the weather since March 21 and delivered a new portion of powdered-rock sample for laboratory analysis on March 23, among other activities.

"We are back to full science operations," said Curiosity Deputy Project Manager Jim Erickson of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

The powder delivered on Saturday came from the rover's first full drilling into a rock to collect a sample. The new portion went into the Sample Analysis at Mars (SAM) instrument inside the rover, which began analyzing this material and had previously analyzed other portions from the same drilling. SAM can analyze samples in several different ways, so multiple portions from the same drilling are useful.

The Rover Environmental Monitoring Station (REMS) is recording weather variables. The Radiation Assessment Detector (RAD) is checking the natural radiation environment at the rover's location inside Gale Crater.

Like many spacecraft, Curiosity carries a pair of main computers, redundant to each other, to have a backup available if one fails. Each of the computers, A-side and B-side, also has other redundant subsystems linked to just that computer. Curiosity is now operating on its B-side, as it did during part of the flight from Earth to Mars. The A-side was most recently used starting a few weeks before landing and continuing until Feb. 28, when engineers commanded a switch to the B-side in response to a memory glitch on the A-side. The A-side now is available as a backup if needed.

Bluish Color in Broken Rock in 'Yellowknife Bay'

Image above: The Mast Camera (Mastcam) on NASA's Mars rover Curiosity showed researchers interesting internal color in this rock called "Sutton_Inlier," which was broken by the rover driving over it. The Mastcam took this image during the 174th Martian day, or sol, of the rover's work on Mars (Jan. 31, 2013). The rock is about 5 inches (12 centimeters) wide at the end closest to the camera. This view is calibrated to estimated "natural" color, or approximately what the colors would look like if we were to view the scene ourselves on Mars. The inside of the rock, which is in the "Yellowknife Bay" area of Gale Crater, is much less red than typical Martian dust and rock surfaces, with a color verging on grayish to bluish. Image credit: NASA/JPL-Caltech/MSSS/ASU.

One aspect of ramping-up activities after switching to the B-side computer has been to check the six engineering cameras that are hard-linked to that computer. The rover's science instruments, including five science cameras, can each be operated by either the A-side or B-side computer, whichever is active. However, each of Curiosity's 12 engineering cameras is linked to just one of the computers. The engineering cameras are the Navigation Camera (Navcam), the Front Hazard-Avoidance Camera (Front Hazcam) and Rear Hazard-Avoidance Camera (Rear Hazcam). Each of those three named cameras has four cameras on it: two stereo pairs of cameras, with one pair linked to each computer. Only the pairs linked to the active computer can be used, and the A-side computer was active from before landing, in August, until Feb. 28.

"This was the first use of the B-side engineering cameras since April 2012, on the way to Mars," said JPL's Justin Maki, team lead for these cameras. "Now we've used them on Mars for the first time, and they've all checked out OK."

Rear view of Mars Science Laboratory (MSL) "Curiosity". Image credit: NASA/JPL-Caltech

Engineers quickly diagnosed a software issue that prompted Curiosity to put itself into a precautionary standby "safe mode" on March 16, and they know how to prevent it from happening again. The rover stayed on its B-side while it was in safe mode and subsequently as science activities resumed.

Upcoming activities include preparations for a moratorium on transmitting commands to Curiosity from April 4 to May 1, while Mars will be passing nearly directly behind the sun from Earth's perspective. The moratorium is a precaution against possible interference by the sun corrupting a command sent to the rover.

NASA's Mars Science Laboratory project is using Curiosity and the rover's 10 science instruments to investigate the environmental history within Gale Crater, a location where the project has found that conditions were long ago favorable for microbial life. JPL, a division of the California Institute of Technology in Pasadena, manages the project for NASA's Science Mission Directorate in Washington.

More information about Curiosity is online at http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ . You can follow the mission on Facebook at: http://www.facebook.com/marscuriosity and on Twitter at: http://www.twitter.com/marscuriosity

Images (mentioned), Text, Credit: NASA / JPL / Guy Webster.

Greetings, Orbiter.ch

Dragon Spacecraft Returns to Earth












SpaceX - Commercial Resupply Services "Dragon" SpX-2 patch.

March 26, 2013

The SpaceX Dragon fired its engines for the last time Tuesday at 11:42 a.m. EDT sending it through the Earth’s atmosphere for a splashdown in the Pacific Ocean at 12:34 p.m. A team of SpaceX engineers, technicians and divers will recover the vehicle and its scientific cargo off the coast of Baja, California, for the journey back to shore which will take about 30 hours.

Dragon's release from Canadarm2 occurred at 6:56 a.m. The Expedition 35 crew commanded the spacecraft to slowly depart from the International Space Station. Ground controllers earlier sent commands to the Canadarm2 to unberth Dragon from the Harmony node at 4:10 a.m.

The SpaceX Dragon spacecraft just prior to splashdown in the Pacific Ocean. Credit: SpaceX

Dragon's return date, originally scheduled for March 25, was postponed due to inclement weather developing near its targeted splashdown site in the Pacific Ocean. The additional day spent attached to the orbiting laboratory will not affect science samples scheduled to return aboard the spacecraft. NASA Television will provide coverage of Dragon's departure beginning at 4 a.m. EDT.

The Dragon spacecraft launched atop the Falcon 9 rocket on the SpaceX-2 commercial resupply mission March 1 from Cape Canaveral Air Force Station in Florida. Two days later Flight Engineer Tom Marshburn captured the Dragon just 32 feet away from the station with the Canadarm2. Ground controllers then took over Canadarm2 operations and berthed Dragon to the Harmony node.

Hatches to the commercial cargo craft were opened about four hours later beginning three weeks of cargo transfer activities. Station crew members swapped 1,200 pounds of cargo delivered to the station with 2,600 pounds of gear to be returned to Earth.

Read about the research gear delivered aboard Dragon: http://www.nasa.gov/mission_pages/station/research/news/research_rides_dragon.html

Experiment gear and space hardware were delivered for NASA and its Russian, Canadian, European and Japanese space station partners. Over twice as much gear was returned including trash, station hardware and biological samples collected and stored in freezers during the course of research for analysis on the ground.


Image above: The SpaceX Dragon is unberthed from the station's Harmony node as the sun begins to rise over the Earth. Credit: NASA.

Dragon is the only space station resupply spacecraft able to return a significant amount of cargo to Earth. It returned about 2,668 pounds (1,210 kilograms) of science samples, equipment and education activities.

Investigations included among the returned cargo could aid in food production during future long-duration space missions and enhance crop production on Earth. Others could help in the development of more efficient solar cells, detergents and semiconductor-based electronics.

Among the returned investigations was the Coarsening in Solid-Liquid Mixtures (CSLM-3) experiment, which also launched to space aboard this Dragon. CLSM-3 studies how crystals known as dendrites form as a metal alloy becomes solid. The research could help engineers develop stronger materials for use in automobile, aircraft and spacecraft parts.

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Dragon Released for Departure, Prepares for Splashdown

Dragon’s rendezvous with the station was delayed by a day after three of four thrusters did not fire as commanded. SpaceX engineers resolved the problem and continued Dragon’s mission to the station after consultation with NASA managers.

A third SpaceX commercial resupply services mission is targeted for launch at the end of September.

Dragon originally performed two demonstration flights, the first in December 2010 for just two orbits and the second in May 2012. The second Dragon demonstration mission actually arrived at the space station, delivered non-essential cargo and stayed for six days after three days of approach and rendezvous tests. Its first official resupply mission under NASA’s Commercial Resupply Services contract was in October 2012 during Expedition 33 and lasted three weeks.

Watch an interview about the CSLM-3 experiment: http://www.nasa.gov/multimedia/videogallery/index.html?media_id=161134741

View the SpaceX Dragon cargo manifest (PDF 93KB): http://www.nasa.gov/pdf/729030main_spacex_2_cargo_manifest.pdf

Images, Video, Text, Credits: SpaceX / NASA / NASA TV.

Cheers, Orbiter.ch

Successful liftoff of the ILS Proton M Breeze M rocket and the SatMex_8


















ILS - SatMex_8 launch poster.


March 26, 2013

 Proton M Breeze M rocket launch

Baikonur Cosmodrome, Kazakhstan, 23:06:48 MSK (Moscow Time) 3:13 pm (GMT) from the launch complex of the platform 200, liftoff of the Proton M Breeze M rocket and the Satmex 8 satellite.

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Launch of SatMex_8 on Proton-M

Successful liftoff of the ILS Proton M Breeze M rocket, which is carrying the Satmex 8 satellite onboard. The three stages of the proton vehicle have performed as planned, and it is up to the Breeze M upper stage to complete the mission.

The Satellite

    Satellite Operator: Satélites Mexicanos S.A. de C.V.
    Satellite Manufacturer: Space Systems/Loral
    Purpose: C- and Ku-band Services
    Platform: SS/L 1300
    Separated Mass: ~5,474 kg
    Satellite Design Life: 15 years

Satmex_8 satellite

Highlights

    1st Satmex Satellite Launched on ILS Proton
    78th ILS Proton Launch Overall
    1st ILS Proton Launch in 2013
    25th Space Systems/Loral Satellite Launched on ILS Proton

An International Launch Services Proton rocket with a Breeze M upper stage will deploy the Satmex 8 satellite. Satmex 8 will provide video distribution, broadband, cellular backhaul and distance learning services in North America and South America.

For more information about International Launch Services (ILS), visit: http://www.ilslaunch.com/

Roscosmos PAO press release: http://www.federalspace.ru/main.php?id=2&nid=19977

Images, Video, Text, Credits: ILS / Roscosmos TV / ILS TV.

Greetings, Orbiter.ch