vendredi 1 mars 2013

Second SpaceX Space Station Resupply Flight Liftoff














SpaceX - Commercial Resupply Services 2.

March 1, 2013


Image above: The SpaceX Falcon 9 rocket, with it's Dragon spacecraft onboard, lifts off from Launch Complex 40 at the Cape Canaveral Air Force Station in Florida. Image credit: NASA TV

The SpaceX Falcon 9 rocket carrying the Dragon spacecraft lifted off at 10:10 a.m. EST from Cape Canaveral Air Force Station in Florida, beginning its mission to resupply the International Space Station. The mission will mark the third trip by a Dragon capsule to the orbiting laboratory, following a demonstration flight in May 2012 and the first resupply mission in October 2012.

video
SpaceX Dragon Launches

SpaceX says all four of Dragon's four thruster pods are now online. Dragon is not expected to berth at the International Space Station tomorrow as planned. NASA and SpaceX are assessing the next steps and berthing opportunities.

Carried by a Falcon 9 rocket, the Dragon spacecraft will ferry 1,268 pounds of supplies for the space station crew and for experiments being conducted aboard the orbiting laboratory.

On March 2, Expedition 34 Commander Kevin Ford and Flight Engineer Tom Marshburn of NASA are scheduled use the station's robot arm to grapple Dragon following its rendezvous with the orbiting outpost. Ground commands will be sent to attach the spacecraft to the Earth-facing port of the station's Harmony module where it will remain for a few weeks while astronauts unload cargo. The crew then will load more than 2,600 pounds of experiment samples and equipment for return to Earth.

 
 SpaceX Dragon spacecraft

Dragon is scheduled for a parachute-assisted splashdown in the Pacific Ocean off the coast of Baja California on March 25.

This SpaceX flight is the second of at least 12 missions to the space station that the company will fly for NASA under the Commercial Resupply Services contract.

For more information about SpaceX, visit: http://www.spacex.com/

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

Greetings, Orbiter.ch

jeudi 28 février 2013

NASA's Van Allen Probes Discover a Surprise Circling Earth










NASA - Van Allen Probes Mission patch.

Feb. 28, 2013

video

Video above: Since their discovery over 50 years ago, the Earth’s Van Allen radiation belts have been considered to consist of two distinct zones of trapped, highly energetic charged particles. Observations from NASA’s Van Allen Probes reveal an isolated third ring in the outer radiation belt. Credit: NASA/Goddard Space Flight Center.

After most NASA science spacecraft launches, researchers wait patiently for months as instruments on board are turned on one at a time, slowly ramped up to full power, and tested to make sure they work at full capacity. It's a rite of passage for any new satellite in space, and such a schedule was in place for the Van Allen Probes when they launched on Aug. 30, 2012, to study two giant belts of radiation that surround Earth.

But a group of scientists on the mission made a case for changing the plan. They asked that the Relativistic Electron Proton Telescope (REPT) be turned on early – just three days after launch -- in order that its observations would overlap with another mission called SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer), that was soon going to de-orbit and re-enter Earth's atmosphere.

It was a lucky decision. Shortly before REPT turned on, solar activity on the sun had sent energy toward Earth that caused the radiation belts to swell. The REPT instrument worked well from the moment it was turned on Sep. 1. It made observations of these new particles trapped in the belts, recording their high energies, and the belts' increased size.

Then something happened no one had ever seen before: the particles settled into a new configuration, showing an extra, third belt extending out into space. Within mere days of launch, the Van Allen Probes showed scientists something that would require rewriting textbooks.

"By the fifth day REPT was on, we could plot out our observations and watch the formation of a third radiation belt," says Shri Kanekal, the deputy mission scientist for the Van Allen Probes at NASA's Goddard Space Flight Center in Greenbelt, Md. and a coauthor of a paper on these results. "We started wondering if there was something wrong with our instruments. We checked everything, but there was nothing wrong with them. The third belt persisted beautifully, day after day, week after week, for four weeks."

The scientists published their results in a paper in the journal Science on Feb. 28, 2013. Incorporating this new configuration into their models of the radiation belts offers scientists new clues to what causes the changing shapes of the belts – a region that can sometimes swell dramatically in response to incoming energy from the sun, impacting satellites and spacecraft or pose potential threats to manned space flight.


Image above: Two giant swaths of radiation, known as the Van Allen Belts, surrounding Earth were discovered in 1958. In 2012, observations from the Van Allen Probes showed that a third belt can sometimes appear. The radiation is shown here in yellow, with green representing the spaces between the belts. Credit: NASA/Van Allen Probes/Goddard Space Flight Center.

The radiation belts, or Van Allen belts, were discovered with the very first launches of satellites in 1958 by James Van Allen. Subsequent missions have observed parts of the belts – including SAMPEX, which observed the belts from below – but what causes such dynamic variation in the belts has remained something of a mystery. Indeed, seemingly similar storms from the sun have at times caused completely different effects in the belts, or have sometimes led to no change at all.

The Van Allen Probes consist of two identical spacecraft with a mission to map out this region with exquisite detail, cataloguing a wide range of energies and particles, and tracking the zoo of magnetic waves that pulse through the area, sometimes kicking particles up to such frenzied speeds that they escape the belts altogether.

"We've had a long run of data from missions like SAMPEX," says Daniel Baker, who is the principal investigator for REPT at the University of Colorado in Boulder and first author on the Science paper. "But we've never been in the very throat of the accelerator operating a few hundred miles above our head, speeding these particles up to incredible velocities."

In its first six months in orbit, the instruments on the Van Allen Probes have worked exceptionally well and scientists are excited about a flood of observations coming in with unprecedented clarity. This is the first time scientists have been able to gather such a complete set of data about the belts, with the added bonus of watching from two separate spacecraft that can better show how events sweep across the area.

Spotting something new in space such as the third radiation belt has more implications than the simple knowledge that a third belt is possible. In a region of space that remains so mysterious, any observations that link certain causes to certain effects adds another piece of information to the puzzle.

Baker likes to compare the radiation belts to the particle storage rings in a particle physics accelerator. In accelerators, magnetic fields are used to hold the particles orbiting in a circle, while energy waves are used to buffet the particles up to ever faster speeds. In such accelerators, everything must be carefully tuned to the size and shape of that ring, and the characteristics of those particles. The Van Allen Belts depend on similar fine-tuning. Given that scientists see the rings only in certain places and at certain times, they can narrow down just which particles and waves must be causing that geometry. Every new set of observations helps narrow the field even further.

"We can offer these new observations to the theorists who model what's going on in the belts," says Kanekal. "Nature presents us with this event – it's there, it's a fact, you can't argue with it -- and now we have to explain why it's the case. Why did the third belt persist for four weeks? Why does it change? All of this information teaches us more about space."


Image above: On Aug. 31, 2012, a giant prominence on the sun erupted, sending out particles and a shock wave that traveled near Earth. This event may have been one of the causes of a third radiation belt that appeared around Earth a few days later, a phenomenon that was observed for the very first time by the newly-launched Van Allen Probes. This image of the prominence before it erupted was captured by NASA's Solar Dynamics Observatory (SDO). Credit: NASA/SDO/AIA/Goddard Space Flight Center.

Scientists already have theories about just what kind of waves sweep out particles in the "slot" region between the first two belts. Now they must devise models to find which waves have the right characteristics to sweep out particles in the new slot region as well. Another tantalizing observation to explore lies in tracking the causes of the slot region back even further: on Aug. 31, 2012, a long filament of solar material that had been hovering in the sun's atmosphere erupted out into space. Baker says that this might have caused the shock wave that led to the formation of the third ring a few days later. In addition, the new belt was virtually annihilated four weeks after it appeared by another powerful interplanetary shock wave from the sun. Being able to watch such an event in action provides even more material for theories about the Van Allen belts.

Despite the 55 years since the radiation belts were first discovered, there is much left to investigate and explain, and within just a few days of launch the Van Allen Probes showed that the belts are still capable of surprises.

NASA's Van Allen Probes. Credit: NASA/Goddard Space Flight Center

"I consider ourselves very fortunate," says Baker. "By turning on our instruments when we did, taking great pride in our engineers and having confidence that the instruments would work immediately and having the cooperation of the sun to drive the system the way it did – it was an extraordinary opportunity. It validates the importance of this mission and how important it is to revisit the Van Allen Belts with new eyes."

The Johns Hopkins University Applied Physics Laboratory (APL) built and operates the twin Van Allen Probes. The Van Allen Probes comprise the second mission in NASA's Living With a Star (LWS) program to explore aspects of the connected sun-Earth system that directly affect life and society. The program is managed by NASA Goddard.

Related Links:

View NASA Press Release: http://www.nasa.gov/home/hqnews/2013/feb/HQ_13-065_Van_Allen_Probes_Belts.html

View briefing materials from the February 28, 2013 news conference: http://www.nasa.gov/mission_pages/rbsp/multimedia/20130228_briefing_materials.html

Images (mentioned), Video (mentioned), Text, Credit: NASA's Goddard Space Flight Center / Karen C. Fox.

Best regards, Orbiter.ch

Fermi's Motion Produces a Study in Spirograph











NASA - Fermi Gamma-ray Space Telescope logo.

Feb. 28, 2013


NASA's Fermi Gamma-ray Space Telescope orbits our planet every 95 minutes, building up increasingly deeper views of the universe with every circuit. This image compresses eight individual frames, from a movie showing 51 months of position and exposure data by Fermi's Large Area Telescope (LAT), into a single snapshot. The pattern reflects numerous motions of the spacecraft, including its orbit around Earth, the precession of its orbital plane, the manner in which the LAT nods north and south on alternate orbits, and more.

The LAT sweeps across the entire sky every three hours, capturing the highest-energy form of light -- gamma rays -- from sources across the universe. These range from supermassive black holes billions of light-years away to intriguing objects in our own galaxy, such as X-ray binaries, supernova remnants and pulsars.

For more information about Fermi Gamma-ray Space Telescope, visit: http://fermi.gsfc.nasa.gov/

Image, Text, Credit: NASA / DOE / Fermi LAT Collaboration.

Cheers, Orbiter.ch

The Birth of a Giant Planet?












ESO - European Southern Observatory logo.

28 February 2013

Candidate protoplanet spotted inside its stellar womb

Artist's impression of a gas giant planet forming in the disc around the young star HD 100546

Astronomers using ESO’s Very Large Telescope have obtained what is likely the first direct observation of a forming planet still embedded in a thick disc of gas and dust. If confirmed, this discovery will greatly improve our understanding of how planets form and allow astronomers to test the current theories against an observable target.

 VLT and Hubble images of the protoplanet system HD 100546

An international team led by Sascha Quanz (ETH Zurich, Switzerland) has studied the disc of gas and dust that surrounds the young star HD 100546, a relatively nearby neighbour located 335 light-years from Earth. They were surprised to find what seems to be a planet in the process of being formed, still embedded in the disc of material around the young star. The candidate planet would be a gas giant similar to Jupiter.

 VLT image of the protoplanet around the young star HD 100546

“So far, planet formation has mostly been a topic tackled by computer simulations,” says Sascha Quanz. “If our discovery is indeed a forming planet, then for the first time scientists will be able to study the planet formation process and the interaction of a forming planet and its natal environment empirically at a very early stage.”

 NASA/ESA Hubble Space Telescope view of the dust disc around the young star HD 100546

HD 100546 is a well-studied object, and it has already been suggested that a giant planet orbits about six times further from the star than the Earth is from the Sun. The newly found planet candidate is located in the outer regions of the system, about ten times further out [1].

 The young star HD 100546 in the southern constellation of Musca

The planet candidate around HD 100546 was detected as a faint blob located in the circumstellar disc revealed thanks to the NACO adaptive optics instrument on ESO’s VLT, combined with pioneering data analysis techniques. The observations were made using a special coronagraph in NACO, which operates at near-infrared wavelengths and suppresses the brilliant light coming from the star at the location of the protoplanet candidate [2].

 Wide-field view of the sky around the young star HD 100546

According to current theory, giant planets grow by capturing some of the gas and dust that remains after the formation of a star [3]. The astronomers have spotted several features in the new image of the disc around HD100546 that support this protoplanet hypothesis. Structures in the dusty circumstellar disc, which could be caused by interactions between the planet and the disc, were revealed close to the detected protoplanet. Also, there are indications that the surroundings of the protoplanet are potentially heated up by the formation process.

video
Flying through the HD 100546 system

Adam Amara, another member of the team, is enthusiastic about the finding. “Exoplanet research is one of the most exciting new frontiers in astronomy, and direct imaging of planets is still a new field, greatly benefiting from recent improvements in instruments and data analysis methods. In this research we used data analysis techniques developed for cosmological research, showing that cross-fertilisation of ideas between fields can lead to extraordinary progress.”

Although the protoplanet is the most likely explanation for the observations, the results of this study require follow-up observations to confirm the existence of the planet and discard other plausible scenarios. Among other explanations, it is possible, although unlikely, that the detected signal could have come from a background source. It is also possible that the newly detected object might not be a protoplanet, but a fully formed planet which was ejected from its original orbit closer to the star. When the new object around HD 100546 is confirmed to be a forming planet embedded in its parent disc of gas and dust, it will become an unique laboratory in which to study the formation process of a new planetary system.

Notes:

[1] The protoplanet candidate orbits about 70 times further from its star than the Earth does from the Sun. This distance is comparable to the size of the orbits of outer Solar System dwarf planets such as Eris and Makemake. This location is controversial, as it does not fit well with current theories of planet formation. It is unclear at present whether the newfound planet candidate has been in its current position for the whole time since it formed or whether it could have migrated from the inner regions.

[2] The team made use of a special feature called an apodised phase plate that increases the contrast of the image close to the star.

[3] To study planet formation, astronomers cannot look at the Solar System, as all the planets in our neighborhood were formed more than four billion years ago. But for many years, theories about planet formation were strongly influenced by what astronomers could see in our local surroundings, as no other planets were known. Since 1995, when the first exoplanet around a sunlike star was discovered, several hundred planetary systems have been found, opening up new opportunities for scientists studying planetary formation. Up to now however, none have been “caught in the act” in the process of being formed, whilst still embedded in the disc of material around their young parent star.

More information:

This research was presented in a paper “A Young Protoplanet Candidate Embedded in the Circumstellar disc of HD 100546”, by S. P. Quanz et al., to appear online in the 28 February 2013 issue of Astrophysical Journal Letters.

The team is composed of Sascha P. Quanz (ETH Zurich, Switzerland), Adam Amara (ETH), Michael R. Meyer (ETH), Matthew A. Kenworthy (Sterrewacht Leiden, Netherlands), Markus Kasper (ESO, Garching, Germany) and Julien H. Girard (ESO, Santiago, Chile).

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”.

Links:

Research paper: http://www.eso.org/public/archives/releases/sciencepapers/eso1310/eso1310a.pdf

Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/

Images, Text, Credits: ESO/L. Calçada/NASA/ESA/Ardila et al./IAU and Sky & Telescope/Digitized Sky Survey 2. Acknowledgement: Davide De Martin / Video: ESO/L. Calçada.

Greetings, Orbiter.ch

mercredi 27 février 2013

NASA's NuSTAR & ESA's XMM-Newton Helps Solve Riddle of Black Hole Spin














NASA - NuStar Mission patch / ESA - XMM-Newton Mission patch.

Feb. 27, 2013


This artist's concept illustrates a supermassive black hole with millions to billions times the mass of our sun. Supermassive black holes are enormously dense objects buried at the hearts of galaxies. Image credit: NASA/JPL-Caltech.

Two X-ray space observatories, NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Space Agency's XMM-Newton, have teamed up to measure definitively, for the first time, the spin rate of a black hole with a mass 2 million times that of our sun.

The supermassive black hole lies at the dust- and gas-filled heart of a galaxy called NGC 1365, and it is spinning almost as fast as Einstein's theory of gravity will allow. The findings, which appear in a new study in the journal Nature, resolve a long-standing debate about similar measurements in other black holes and will lead to a better understanding of how black holes and galaxies evolve.

"This is hugely important to the field of black hole science," said Lou Kaluzienski, a NuSTAR program scientist at NASA Headquarters in Washington.

NASA's Nuclear Spectroscopic Telescope Array (NuSTAR). Image credit: NASA/JPL-Caltech

The observations also are a powerful test of Einstein's theory of general relativity, which says gravity can bend space-time, the fabric that shapes our universe, and the light that travels through it.

"We can trace matter as it swirls into a black hole using X-rays emitted from regions very close to the black hole," said the coauthor of a new study, NuSTAR principal investigator Fiona Harrison of the California Institute of Technology in Pasadena. "The radiation we see is warped and distorted by the motions of particles and the black hole's incredibly strong gravity."

NuSTAR, an Explorer-class mission launched in June 2012, is designed to detect the highest-energy X-ray light in great detail. It complements telescopes that observe lower-energy X-ray light, such as XMM-Newton and NASA's Chandra X-ray Observatory. Scientists use these and other telescopes to estimate the rates at which black holes spin.


Image above: Scientists measure the spin rates of supermassive black holes by spreading the X-ray light into different colors. Image credit: NASA/JPL-Caltech.

Until now, these measurements were not certain because clouds of gas could have been obscuring the black holes and confusing the results. With help from XMM-Newton, NuSTAR was able to see a broader range of X-ray energies and penetrate deeper into the region around the black hole. The new data demonstrate that X-rays are not being warped by the clouds, but by the tremendous gravity of the black hole. This proves that spin rates of supermassive black holes can be determined conclusively.

"If I could have added one instrument to XMM-Newton, it would have been a telescope like NuSTAR," said Norbert Schartel, XMM-Newton Project Scientist at the European Space Astronomy Center in Madrid. "The high-energy X-rays provided an essential missing puzzle piece for solving this problem."

Measuring the spin of a supermassive black hole is fundamental to understanding its past history and that of its host galaxy.

ESA's XMM-Newton spacecraft. Image credit: ESA

"These monsters, with masses from millions to billions of times that of the sun, are formed as small seeds in the early universe and grow by swallowing stars and gas in their host galaxies, merging with other giant black holes when galaxies collide, or both," said the study's lead author, Guido Risaliti of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and the Italian National Institute for Astrophysics.

Supermassive black holes are surrounded by pancake-like accretion disks, formed as their gravity pulls matter inward. Einstein's theory predicts the faster a black hole spins, the closer the accretion disk lies to the black hole. The closer the accretion disk is, the more gravity from the black hole will warp X-ray light streaming off the disk.

Astronomers look for these warping effects by analyzing X-ray light emitted by iron circulating in the accretion disk. In the new study, they used both XMM-Newton and NuSTAR to simultaneously observe the black hole in NGC 1365. While XMM-Newton revealed that light from the iron was being warped, NuSTAR proved that this distortion was coming from the gravity of the black hole and not gas clouds in the vicinity. NuSTAR's higher-energy X-ray data showed that the iron was so close to the black hole that its gravity must be causing the warping effects.

With the possibility of obscuring clouds ruled out, scientists can now use the distortions in the iron signature to measure the black hole's spin rate. The findings apply to several other black holes as well, removing the uncertainty in the previously measured spin rates.

The California Institute of Technology in Pasadena manages JPL for NASA.

For more information on NASA's NuSTAR mission, visit: http://www.nasa.gov/nustar

For more information on ESA's XMM-Newton mission, visit: http://www.esa.int/Our_Activities/Space_Science/XMM-Newton_overview

Images, (mentioned), Text, Credits: NASA / J.D. Harrington / JPL / Whitney Clavin / ESA.

Best regards, Orbiter.ch

NASA's Aquarius Sees Salty Shifts












NASA - Aquarius (SAC-D) Mission patch.

Feb. 27, 2013

video

This video provides a global tour of sea surface salinity using measurements taken by NASA’s Aquarius instrument aboard the Aquarius/SAC-D spacecraft, from December 2011 through December 2012. Red represents areas of high salinity, while blue represents areas of low salinity. Aquarius is a focused effort to measure sea surface salinity and will provide the global view of salinity variability needed for climate studies. The mission is a collaboration between NASA and the Space Agency of Argentina (Comisión Nacional de Actividades Espaciales).

The colorful images chronicle the seasonal stirrings of our salty world: Pulses of freshwater gush from the Amazon River’s mouth; an invisible seam divides the salty Arabian Sea from the fresher waters of the Bay of Bengal; a large patch of freshwater appears in the eastern tropical Pacific in the winter. These and other changes in ocean salinity patterns are revealed by the first full year of surface salinity data captured by NASA’s Aquarius instrument.

“With a bit more than a year of data, we are seeing some surprising patterns, especially in the tropics,” said Aquarius Principal Investigator Gary Lagerloef, of Earth & Space Research in Seattle. “We see features evolve rapidly over time.”


Image above: NASA¹s Aquarius instrument has been orbiting the Earth for a year, measuring changes in salinity, or salt concentration, in the surface of the oceans. The Aquarius team released last September this first global map of ocean saltiness, a composite of the first two and a half weeks of data since the instrument became operational on August 25. Credit: NASA/GSFC/JPL-Caltech.

Launched June 10, 2011, aboard the Argentine spacecraft Aquarius/Satélite de Aplicaciones Científicas (SAC)-D, Aquarius is NASA’s first satellite instrument specifically built to study the salt content of ocean surface waters. Salinity variations, one of the main drivers of ocean circulation, are closely connected with the cycling of freshwater around the planet and provide scientists with valuable information on how the changing global climate is altering global rainfall patterns.


Image above: A Delta II rocket carrying the international Aquarius/SAC-D observatory launched from Vandenberg Air Force Base in California, on June 10, 2011. Credit: NASA/Bill Ingalls.

The salinity sensor detects the microwave emissivity of the top 1 to 2 centimeters (about an inch) of ocean water – a physical property that varies depending on temperature and saltiness. The instrument collects data in 386 kilometer-wide (240-mile) swaths in an orbit designed to obtain a complete survey of global salinity of ice-free oceans every seven days.

The Changing Ocean

The animated version of Aquarius’ first year of data unveils a world of varying salinity patterns. The Arabian Sea, nestled up against the dry Middle East, appears much saltier than the neighboring Bay of Bengal, which gets showered by intense monsoon rains and receives freshwater discharges from the Ganges and other large rivers. Another mighty river, the Amazon, releases a large freshwater plume that heads east toward Africa or bends up north to the Caribbean, depending on the prevailing seasonal currents. Pools of freshwater carried by ocean currents from the central Pacific Ocean’s regions of heavy rainfall pile up next to Panama’s coast, while the Mediterranean Sea sticks out in the Aquarius maps as a very salty sea.

One of the features that stand out most clearly is a large patch of highly saline water across the North Atlantic. This area, the saltiest anywhere in the open ocean, is analogous to deserts on land, where little rainfall and a lot of evaporation occur. A NASA-funded expedition, the Salinity Processes in the Upper Ocean Regional Study (SPURS), traveled to the North Atlantic’s saltiest spot last fall to analyze the causes behind this high salt concentration and to validate Aquarius measurements.

“My conclusion after five weeks out at sea and analyzing five weekly maps of salinity from Aquarius while we were there was that indeed, the patterns of salinity variation seen from Aquarius and by the ship were similar,” said Eric Lindstrom, NASA’s physical oceanography program scientist, of NASA Headquarters, Washington, and a participant of the SPURS research cruise.

video
 Animation of how Aquarius works

Future goals

“The Aquarius prime mission is scheduled to run for three years but there is no reason to think that the instrument could not be able to provide valuable data for much longer than that,” said Gene Carl Feldman, Aquarius project manager at NASA’s Goddard Space Flight Center in Greenbelt, Md. “The instrument has been performing flawlessly and our colleagues in Argentina are doing a fantastic job running the spacecraft, providing us a nice, stable ride.”

In future years, one of the main goals of the Aquarius team is to figure out ways to fine-tune the readings and retrieve data closer to the coasts and the poles. Land and ice emit very bright microwave emissions that swamp the signal read by the satellite. At the poles, there’s the added complication that cold polar waters require very large changes in their salt concentration to modify their microwave signal.

Still, the Aquarius team was surprised by how close to the coast the instrument is already able to collect salinity measurements.

“The fact that we’re getting areas, particularly around islands in the Pacific, that are not obviously badly contaminated is pretty remarkable. It says that our ability to screen out land contamination seems to be working quite well,” Feldman said.

Another factor that affects salinity readings is intense rainfall. Heavy rain can affect salinity readings by attenuating the microwave signal Aquarius reads off the ocean surface as it travels through the soaked atmosphere. Rainfall can also create roughness and shallow pools of fresh water on the ocean surface. In the future, the Aquarius team wants to use another instrument aboard Aquarius/SAC-D, the Argentine-built Microwave Radiometer, to gauge the presence of intense rain simultaneously to salinity readings, so that scientists can flag data collected during heavy rainfall.

video

This visualization shows changes in global sea surface salinity, as measured by NASA’s Aquarius instrument aboard the Aquarius/SAC-D spacecraft, from December 2011 through December 2012. Red represents areas of high salinity, while blue represents areas of low salinity. Aquarius is a focused effort to measure sea surface salinity and will provide the global view of salinity variability needed for climate studies. The mission is a collaboration between NASA and the Space Agency of Argentina (Comisión Nacional de Actividades Espaciales).

An ultimate goal is combining the Aquarius measurements to those of its European counterpart, the Soil Moisture and Ocean Salinity satellite (SMOS) to produce more accurate and finer maps of ocean salinity. In addition, the Aquarius team, in collaboration with researchers at the U.S. Department of Agriculture, is about to release its first global soil moisture dataset, which will complement SMOS’ soil moisture measurements.

“The first year of the Aquarius mission has mostly been about understanding how the instruments and algorithms are performing,” Feldman said. “Now that we have overcome the major hurdles, we can really begin to focus on understanding what the data are telling us about how the ocean works, how it affects weather and climate, and what new insights we can gain by having these remarkable salinity measurements.”

Aquarius was built by NASA's Jet Propulsion Laboratory, and Goddard. JPL managed Aquarius through its commissioning phase and is archiving mission data. Goddard now manages Aquarius mission operations and processes science data. Argentina's space agency, Comisión Nacional de Actividades Espaciales (CONAE), provided the SAC-D spacecraft, optical camera, thermal camera with Canada, microwave radiometer, sensors from various Argentine institutions and the mission operations center. France and Italy also contributed instruments.

For more information about Aquarius Mission, visit: http://aquarius.nasa.gov/

Images (mentioned), Videos (mentioned), Text, Credit: NASA's Goddard Space Flight Center/Maria-Jose Vinas.

Greetings, Orbiter.ch

mardi 26 février 2013

ISRO - Success launch for PSLV-C20 / SARAL Mission











ISRO logo.


February 25, 2013

 PSLV-C20 / SARAL launch

An Indian Polar Satellite Launch Vehicle (PSLV) rocket successfully launched on February 25th 2013 at 12:31 UTC carrying Saral and 6 commercial secondary payloads into orbit from the Satish Dhawan Space Centre.

video
Launch of Indian PSLV Rocket with Saral

ISRO's Polar Satellite Launch Vehicle, PSLV-C20, successfully launched the joint Indo-French Satellite, SARAL, today in its twenty third flight from Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota. Six other satellites, namely, UNIBRITE (NLS 8.1) and BRITE (NLS 8.2) from Austria, SAPPHIRE and NEOSSAT from Canada, AAUSAT-3 (NLS 8.3) from Denmark; and STRaND-1 from the United Kingdom, have also been launched into their planned orbits along with SARAL.

At the completion of the countdown, PSLV-C20 lifted off from the First Launch Pad at SDSC SHAR, at 1801 hrs (IST) with the ignition of the first stage of the launch vehicle. The important flight events, namely, stage ignitions, heat-shield separation, stage separations and satellite injections took place exactly as planned.

After a flight of 17 minutes 55 seconds, the main payload, SARAL, weighing 407 kg was injected to an orbit very close to the intended orbit. Following this, the six auxiliary satellites were also successfully injected.

SARAL ocean altimetry satellite

This has been the twenty second successive successful launch of ISRO's workhorse launch vehicle PSLV. Since its first successful launch in 1994, PSLV has launched 27 Indian satellites and 35 satellites for customers from abroad, including the satellites launched today. It has also launched India's geosynchronous satellites, Kalpana-1 and GSAT-12, thereby proving its versatility. PSLV also launched India's first spacecraft mission to moon, Chandrayaan-1, in 2008. It is scheduled to launch India's first interplanetary mission, the Mars Orbiter Mission (MOM) spacecraft, by the end of this year.

Satellite with Argos and Altika (SARAL) is an oceanographic satellite jointly developed by ISRO and the French Space Agency CNES. The satellite is built by ISRO, whereas CNES contributed the ARGOS and ALTIKA payloads. Data from SARAL will be useful for researchers besides having many practical applications like marine meteorology and sea state forecasting, climate monitoring, continental ice studies, environmental monitoring, protection of biodiversity and improvement in maritime security.

ISRO Telemetry, Tracking and Command Network (ISTRAC) in Bangalore took over the SARAL's monitoring and control operations immediately after its injection. Following the automatic deployment of SARAL's solar panels, shortly after reaching orbit, all the subsequent operations are proceeding normally.

For more information about ISRO, visit: http://www.isro.org/

Images, Video, Text, Credits: Indian Space Research Organization (ISRO) / CNES.

Greetings, Orbiter.ch

lundi 25 février 2013

Saturn's North Polar Hexagon










NASA / ESA - Cassini Mission International patch.

Feb. 25, 2013


Saturn's north polar hexagon basks in the Sun's light now that spring has come to the northern hemisphere. Many smaller storms dot the north polar region and Saturn's signature rings, which appear to disappear on account of Saturn's shadow, put in an appearance in the background.

The image was taken with the Cassini spacecraft's wide-angle camera on Nov. 27, 2012 using a spectral filter sensitive to wavelengths of near-infrared light centered at 750 nanometers.

The view was acquired at a distance of approximately 403,000 miles (649,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 21 degrees. Image scale is 22 miles (35 kilometers) per pixel.

For information about Cassini, visit: http://www.nasa.gov/cassini and http://www.esa.int/esaMI/Cassini-Huygens/

Image, Text, Credits:  Credit: NASA / ESA / JPL-Caltech / Space Science Institute.

Greetings, Orbiter.ch

Cosmic eye‏












ESA - Hubble Space Telescope patch.

25 February 2013

 Planetary nebula ESO 456-67

It may look like something from The Lord of the Rings, but this fiery swirl is actually a planetary nebula known as ESO 456-67. Set against a backdrop of bright stars, the rust-coloured object lies in the constellation of Sagittarius (The Archer), in the southern sky.

Despite the name, these ethereal objects have nothing at all to do with planets. The misnomer came about over a century ago, when the first astronomers to observe them only had small, poor-quality telescopes. Through these, the nebulae looked small, compact and planet-like.

When a star like the Sun approaches the end of its life, it flings material out into space. Planetary nebulae are the intricate, glowing shells of dust and gas pushed outwards from such a star. At their centres lie the remnants of the original stars themselves – small, dense white dwarf stars.

In this image of ESO 456-67 taken by the Hubble Space Telescope, it is possible to see the various layers of material expelled by the central star. Each appears in a different hue – red, orange, yellow and green-tinted bands of gas, with clear patches of space at the heart of the nebula.

It is not fully understood how planetary nebulae form such a wide variety of shapes and structures. Some appear to be spherical, some elliptical, others shoot material in waves from their polar regions, some look like hourglasses or figures of eight, and others resemble large, messy stellar explosions – to describe but a few.

A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Jean-Christophe Lambry.

Related links:

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

Hubble's Universe: http://spacetelescope.org/

Hubble overview: http://www.esa.int/Our_Activities/Space_Science/Hubble_overview

Hubble in depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=31

Image, Text, Credits: ESA / Hubble & NASA. Acknowledgement: J.-C. Lambry.

Best regards, Orbiter.ch