A Beautiful End to a Star’s Life

NASA - Chandra X-ray Observatory patch.

July 12, 201

Image above: Composite image of planetary nebula NGC 2392. Image Credit: X-ray: NASA/CXC/IAA-CSIC/N. Ruiz et al; Optical: NASA/STScI.

Stars like the Sun can become remarkably photogenic at the end of their life. A good example is NGC 2392, which is located about 4,200 light years from Earth. NGC 2392, nicknamed the "Eskimo Nebula", is what astronomers call a planetary nebula. This designation, however, is deceiving because planetary nebulas actually have nothing to do with planets. The term is simply a historic relic since these objects looked like planetary disks to astronomers in earlier times looking through small optical telescopes.

Instead, planetary nebulas form when a star uses up all of the hydrogen in its core -- an event our Sun will go through in about five billion years. When this happens, the star begins to cool and expand, increasing its radius by tens to hundreds of times its original size. Eventually, the outer layers of the star are carried away by a thick 50,000 kilometer per hour wind, leaving behind a hot core. This hot core has a surface temperature of about 50,000 degrees Celsius, and is ejecting its outer layers in a much faster wind traveling six million kilometers per hour. The radiation from the hot star and the interaction of its fast wind with the slower wind creates the complex and filamentary shell of a planetary nebula. Eventually the remnant star will collapse to form a white dwarf star.

Now days, astronomers using space-based telescopes are able to observe planetary nebulas such as NGC 2392 in ways their scientific ancestors probably could never imagine. This composite image of NGC 2392 contains X-ray data from NASA's Chandra X-ray Observatory in purple showing the location of million-degree gas near the center of the planetary nebula. Data from the Hubble Space Telescope show – colored red, green, and blue – the intricate pattern of the outer layers of the star that have been ejected. The comet-shaped filaments form when the faster wind and radiation from the central star interact with cooler shells of dust and gas that were already ejected by the star.

NASA's Chandra X-ray Observatory. NASA / CXC

The observations of NGC 2392 were part of a study of three planetary nebulas with hot gas in their center. The Chandra data show that NGC 2392 has unusually high levels of X-ray emission compared to the other two. This leads researchers to deduce that there is an unseen companion to the hot central star in NGC 2392. The interaction between a pair of binary stars could explain the elevated X-ray emission found there. Meanwhile, the fainter X-ray emission observed in the two other planetary nebulas in the sample – IC 418 and NGC 6826 – is likely produced by shock fronts (like sonic booms) in the wind from the central star. A composite image of NGC 6826 was included in a gallery of planetary nebulas released in 2012. [http://chandra.harvard.edu/photo/2012/pne/]

A paper describing these results is available online and was published in the April 10th, 2013 issue of The Astrophysical Journal. The first author is Nieves Ruiz of the Instituto de Astrofísica de Andalucía (IAA-CSIC) in Granada, Spain, and the other authors are You-Hua Chu, and Robert Gruendl from the University of Illinois, Urbana; Martín Guerrero from the Instituto de Astrofísica de Andalucía (IAA-CSIC) in Granada, Spain, and Ralf Jacob, Detlef Schönberner and Matthias Steffen from the Leibniz-Institut Für Astrophysik in Potsdam (AIP), Germany.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

Chandra's Flickr photoset: http://www.flickr.com/photos/nasamarshall/sets/72157606205297786/

Paper describing these results: http://lanl.arxiv.org/abs/1302.3886

Images (mentioned), Text, Credits: NASA / J.D. Harrington / Marshall Space Flight Center / Janet Anderson / Chandra X-ray Center / Megan Watzke.

Greetings, Orbiter.ch

Hubble spots azure blue planet

ESA - Hubble Space Telescope logo.

11 July 2013

True colour of exoplanet measured for the first time

Artist’s impression of the deep blue planet HD 189733b

Astronomers using the NASA/ESA Hubble Space Telescope have, for the first time, determined the true colour of a planet orbiting another star. If seen up close this planet, known as HD 189733b, would be a deep azure blue, reminiscent of Earth’s colour as seen from space.

But that's where the similarities end. This "deep blue dot" is a huge gas giant orbiting very close to its host star. The planet's atmosphere is scorching with a temperature of over 1000 degrees Celsius, and it rains glass, sideways, in howling 7000 kilometre-per-hour winds [1].

Wide-field view of HD 189733b and surroundings (DSS2 excerpt, ground-based image)

At a distance of 63 light-years from us, this turbulent alien world is one of the nearest exoplanets to Earth that can be seen crossing the face of its star. It has been intensively studied by Hubble and other telescopes, and its atmosphere has been found to be dramatically changeable and exotic, with hazes and violent flares (heic0720, heic1209). Now, this planet is the subject of an important first: the first measurement of an exoplanet's visible colour.

"This planet has been studied well in the past, both by ourselves and other teams," says Frédéric Pont of the University of Exeter, UK, leader of the Hubble observing programme and an author of this new paper. "But measuring its colour is a real first — we can actually imagine what this planet would look like if we were able to look at it directly."

Wide-field view of the Summer Triangle (ground-based image)

In order to measure what this planet would look like to our eyes, the astronomers measured how much light was reflected off the surface of HD 189733b — a property known as albedo [2].

HD 189733b is faint and close to its star. To isolate the planet's light from this starlight, the team used Hubble's Space Telescope Imaging Spectrograph (STIS) to peer at the system before, during, and after the planet passed behind its host star as it orbited. As it slipped behind its star, the light reflected from the planet was temporarily blocked from view, and the amount of light observed from the system dropped. But this technique also shows how the light changes in other ways — for example, its colour [3].

Exotic blue planet HD 189733b (artist’s impression)

"We saw the brightness of the whole system drop in the blue part of the spectrum when the planet passed behind its star," explains Tom Evans of the University of Oxford, UK, first author of the paper. "From this, we can gather that the planet is blue, because the signal remained constant at the other colours we measured."

The planet's azure blue colour does not come from the reflection of a tropical ocean, but is due to a hazy, turbulent atmosphere thought to be laced with silicate particles, which scatter blue light [4]. Earlier observations using different methods have reported evidence for scattering of blue light on the planet, but these most recent Hubble observations give robust confirming evidence, say the researchers.

Exotic blue planet HD 189733b (labelled artist’s impression)

HD 189733b presented a favourable case for these kinds of measurements as it belongs to a class of planets known as "hot Jupiters". These massive planets are similar in size to the gas giants in the Solar System, but instead lie very close to their parent star — this size and proximity to their star make them perfect subjects for exoplanet hunting. We know that hot Jupiters are numerous throughout the Universe. As we do not have one close to home in our own Solar System, studies of planets like HD 189733b are important to help us understand these dramatic objects.

The colour of HD 189733b compared to our Solar System

"It's difficult to know exactly what causes the colour of a planet's atmosphere, even for planets in the Solar System," says Pont [5]. "But these new observations add another piece to the puzzle over the nature and atmosphere of HD 189733b. We are slowly painting a more complete picture of this exotic planet."

Notes:

[1] In 2007 NASA's Spitzer Space Telescope measured the infrared light from the planet, producing one of the first ever temperature maps for an exoplanet. The map shows that day- and night-side temperatures differ by about 260 degrees Celsius, causing fierce winds to roar across the planet. The condensation temperature of the silicates (over 1300 degrees Celsius) mean these particles could form very small grains of glass in the atmosphere.

Blue planet HD 189733b around its host star (artist’s impression)

[2] Albedo is a measure of how much incident radiation is reflected. The greater the albedo, the greater the amount of light reflected. This value ranges from 0 to 1, with 1 being perfect reflectivity and 0 being a completely black surface. The Earth has an albedo of around 0.4.

[3] This technique is possible because the planet's orbit is tilted edge-on as viewed from Earth, so that it routinely passes in front of and behind the star. When the planet passes behind its host star, the light received from the system drops by about one part in 10 000.

A zoom to the star HD 189733

[4] The deep blue colour of HD 189733b is consistent with the "red sunset of HD 189733b" result from the transit spectrum (heic0720). If sodium absorbs red light and dust scatters red light, the atmosphere will redden light shining through it, but will appear blue in reflected light.

[5] The colours of Jupiter and Venus are both due to unknown particles within the atmospheres of the planets. Earth looks blue from space because the oceans absorb red and green wavelengths more strongly than blue ones, and reflect the blueish hue of our sky. The shorter blue wavelengths of sunlight are selectively scattered by oxygen and nitrogen molecules in our atmosphere via a process called Rayleigh scattering.

Notes for editors:

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

The new paper, titled "The deep blue colour of HD 189733b: albedo measurements with HST/STIS at visible wavelengths", will appear in the 1 August issue of the journal Astrophysical Journal Letters.

[1] The international team of astronomers in this study consists of T. Evans (University of Oxford, UK), F. Pont (University of Exeter, UK), D. K. Sing (University of Exeter, UK), S. Aigrain (University of Oxford, UK), J. K. Barstow (University of Oxford, UK), J-M. Désert (California Institute of Technology, USA; Sagan Postdoctoral Fellow), N. Gibson (European Southern Observatory, Germany), K. Heng (University of Bern, Switzerland), H. A. Knutson (California Institute of Technology, USA) and A. Lecavelier des Etangs (Universite Pierre et Marie Curie, France).

Links:

Science paper: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1311.pdf

ESA/Hubble release: Hazy red sunset on extrasolar planet: http://www.spacetelescope.org/news/heic0720/

ESA/Hubble release: Dramatic change spotted on a faraway planet: http://www.spacetelescope.org/news/heic1209/

Exoclimes website: http://www.exoclimes.com/about/

NASA press release: http://hubblesite.org/newscenter/archive/releases/2013/25/

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

Images, Videos, Text, Credits: ESA / M. Kornmesser / G. Bacon / NASA and the Digitized Sky Survey 2.  Acknowledgment: Davide De Martin (ESA / Hubble)/A. Fujii / AURA / STScI.

Best regards, Orbiter.ch

Passed correction orbit of the International Space Station

ISS - International Space Station patch.

10.07.2013

According to the International Space Station July 10, 2013 was the correction of its orbit.

According to calculations by the service ballistic and navigation support the Mission Control Center FSUE engines TsNIIMash European cargo spacecraft ATV-4 "Albert Einstein" were included at 09 hours and 35 minutes Moscow time. According to the telemetry duration of the engines was 598 seconds. As a result of the dynamic operation of ISS received increment speed of 1.45 m / s.

The average height of the orbit of the station increased by 2.5 km and reached 417.2 km.

International Space Station (ISS)

After performing the correction parameters of the ISS are the following:

     • minimum height above the surface of the Earth - 414.1 km;
     • maximum height above the surface of the Earth - 436.1 km;
     • period - 92.866 min.;
     • Inclination - 51.651 degrees.

The correction was made to form a working orbit station before flying cargo spacecraft "Progress M-20M", the launch of which is scheduled for July 28, 2013.

Roscosmos Press Release: http://www.federalspace.ru/main.php?id=2&nid=20206

Image, Text, Credits: Press service of the Russian Federal Space Agency and the Federal State Unitary Enterprise TsNIIMash / NASA / Translation: Orbiter.ch Aerospace.

Greetings, Orbiter.ch

NASA’s IBEX Provides First View Of the Solar System’s Tail

NASA - IBEX Mission patch.

July 10, 2013

 NASA IBEX Provides First View of the Solar System's Tail

Video above: NASA's Interstellar Boundary Explorer has observed and described the solar system's tail for the first time. Video Credit: NASA/Goddard Space Flight Center.

It has long been assumed that our solar system, like a comet, has a tail. Just as any object moving through another medium – for example, a meteor traveling through Earth’s atmosphere – causes the particles to form a stream trailing off behind it. But the tail of our solar bubble, called the heliosphere, has never actually been observed, until now.

NASA’s Interstellar Boundary Explorer, or IBEX, has mapped the boundaries of the tail of the heliosphere, something that has never before been possible. Scientists describe this tail, called the heliotail, in detail in a paper published on July 10, 2013, in The Astrophysical Journal. By combining observations from the first three years of IBEX imagery, the team mapped out a tail that shows a combination of fast and slow moving particles. There are two lobes of slower particles on the sides, faster particles above and below, with the entire structure twisted, as it experiences the pushing and pulling of magnetic fields outside the solar system.

Image above: This data from NASA’s Interstellar Boundary Explorer shows what it observed looking down the solar system’s tail. The yellow and red colors represent areas of slow-moving particles, and the blue represents the fast-moving particles. Image Credit:
NASA/IBEX.

By examining the neutral atoms, IBEX made the first observations of the heliotail,” said David McComas, lead author on the paper and principal investigator for IBEX at Southwest Research Institute in San Antonio, Texas. “Many models have suggested the heliotail might be like this or like that, but we’ve had no observations. We always drew pictures where the tail of the heliosphere just disappears off the page, since we couldn’t even speculate about what it really looked like.”

While telescopes have spotted such tails around other stars, it has been difficult to see whether our star also had one. Pioneer 10 was headed in that direction after it crossed the orbit of Neptune in 1983. However, it lost power in 2003 before it moved into the tail so we have no data from spacecraft directly in the tail. Watching it from afar is hard, because the particles in the tail, and throughout the heliosphere, don’t shine, so they can’t be seen conventionally.

IBEX, on the other hand, can map such regions by measuring neutral particles created by collisions at the heliosphere’s boundaries. This technique, called energetic neutral atom imaging, relies on the fact that the paths of neutral particles aren’t affected by the heliosphere’s magnetic fields. The particles travel in a straight line from collision to IBEX. Consequently, observing where the neutral particles came from describes what’s going on in these distant regions.

Image above: Other stars show tails that trail behind them like a comet’s tail. Scientists used NASA’s Interstellar Boundary Explorer to confirm that our solar system has one too. From top left and going counter clockwise, the stars shown are: LLOrionis; BZ Cam; and Mira. Image Credit: NASA/HST/R.Casalegno/GALEX.

“Using neutral atoms, IBEX can observe far away structures, even from Earth orbit,” said Eric Christian, IBEX mission scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “And IBEX scans the entire sky, so it has given us our first data about what the tail of the heliosphere looks like, an important part of understanding our place in and movement through the galaxy.”

The journey for these neutral atoms begins years before it hits the IBEX instruments. The solar wind blowing out from the sun streams out in all directions, moving far past the furthest planets, eventually slowing down and bending back along the tail, in response to the pressure from the inflowing interstellar material. The particles join a mass migration of particles moving backward inside the boundary of the heliosphere – a thin layer called the heliopause.

While this is happening, a steady stream of slower, neutral atoms originating from elsewhere in the galaxy, travel across the solar system. When one of these neutral atoms collides with one of the faster charged particles, they can exchange an electron. The result can be a slow charged particle and a fast neutral atom. The neutral is no longer bound to the magnetic fields, and instead speeds straight off in whatever direction it was pointed at that moment. Some of these travel for years until they are detected by IBEX.

Solar Neutral Particles

Video above: This animation shows the path a particle takes from the sun, over the course of years, before colliding with one of IBEX’s detectors. The animation shows a charged solar particle leaving the sun, following the magnetic field lines out to the solar system’s boundary, the heliosheath. Video Credit:
NASA/Goddard Space Flight Center.

“By collecting these energetic neutral atoms, IBEX provides maps of the original charged particles,” said McComas. “The structures in the heliotail are invisible to our eyes, but we can use this trick to remotely image the outermost regions of our heliosphere.”

Early results from IBEX on the heliotail originally suggested there might just be a small region of slow-moving wind down the heliotail, but once scientists had collected enough data they realized they had initially seen only part of the picture. Based on the map of the heliotail they have now provided, someone looking straight down the tail sees a shape a little like a four-leaf clover. The two side leaves are filled with slow moving particles, and the upper and lower leaves with fast ones. This shape makes sense, given the fact that the sun has been sending out mostly fast solar wind near its poles, and slower wind near its equator for the last few years – a common pattern in the most recent phase of the sun’s 11-year activity cycle.

The four-leaf clover does not align perfectly with the sun, however. The entire shape is rotated slightly, indicating that as it moves further away from the sun and its magnetic influence, the charged particles have begun to be nudged into a new orientation, aligning with the magnetic fields from the local galaxy. Scientists still do not know how long the tail is.

“The tail is our footprint on the galaxy, and it’s exciting that we’re starting to understand the structure of it,” said Christian. “The next step is to incorporate these observations into our models and start the process of really understanding our heliopshere.”

Scientists can test their computer simulations of the heliosphere against the new observations and improve their models as needed. Together, data from instruments in space and analysis at labs on the ground will continue to improve our understanding of the comet-like tail streaming out behind us.

IBEX is a NASA Heliophysics Small Explorer. The Southwest Research Institute leads IBEX with teams of national and international partners. Goddard manages the Explorers Program for NASA's Science Mission Directorate in Washington.

For more information about IBEX science and mission, visit: http://nasa.gov/IBEX

For high resolution media, visit: http://svs.gsfc.nasa.gov/goto?11301

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

Cheers, Orbiter.ch

ALMA Prenatal Scan Reveals Embryonic Monster Star

ESO - European Southern Observatory logo.

10 July 2013

 ALMA observes the birth of a monster star

New observations using the Atacama Large Millimeter/submillimeter array (ALMA) have given astronomers the best view yet of a monster star in the process of forming within a dark cloud. A stellar womb with over 500 times the mass of the Sun has been found — the largest ever seen in the Milky Way — and it is still growing. The embryonic star within the cloud is hungrily feeding on material that is racing inwards. The cloud is expected to give birth to a very brilliant star with up to 100 times the mass of the Sun.

The most massive and brightest stars in the galaxy form within cool and dark clouds but the process remains not just shrouded in dust, but also in mystery [1]. An international team of astronomers has now used ALMA to perform a microwave prenatal scan to get a clearer look at the formation of one such monster star that is located around 11 000 light-years away, in a cloud known as the Spitzer Dark Cloud (SDC) 335.579-0.292.

The location of a monster embryonic star in the constellation of Norma

There are two theories on the formation of the most massive stars. One suggests that the parental dark cloud fragments, creating several small cores that collapse on their own and eventually form stars. The other is more dramatic: the entire cloud begins to collapse inwards, with material racing towards the cloud’s centre to form one or more massive behemoths there. A team led by Nicolas Peretto of CEA/AIM Paris-Saclay, France, and Cardiff University, UK, realised that ALMA was the perfect tool to help find out what was really happening.

SDC335.579-0.292 was first revealed as a dramatic environment of dark, dense filaments of gas and dust through observations with NASA’s Spitzer Space Telescope and ESA’s Herschel Space Observatory. Now the team has used the unique sensitivity of ALMA to look in detail at both the amount of dust and the motion of the gas moving around within the dark cloud — and they have found a true monster.

Wide-field view of the sky around SDC 335.579-0.292

“The remarkable observations from ALMA allowed us to get the first really in-depth look at what was going on within this cloud,” says Peretto. “We wanted to see how monster stars form and grow, and we certainly achieved our aim! One of the sources we have found is an absolute giant — the largest protostellar core ever spotted in the Milky Way."

This core — the womb of the embryonic star — has over 500 times the mass of our Sun swirling around within it [2]. And the ALMA observations show that much more material is still flowing inwards and increasing the mass still further. This material will eventually collapse to form a young star up to 100 times as massive as our home star — a very rare beast.

The birth of a monster star seen at different wavelengths of light (click for enlarge)

“Even though we already believed that the region was a good candidate for being a massive star-forming cloud, we were not expecting to find such a massive embryonic star at its centre,” says Peretto. “This object is expected to form a star that is up to 100 times more massive than the Sun. Only about one in ten thousand of all the stars in the Milky Way reach that kind of mass!”

"Not only are these stars rare, but their birth is extremely rapid and their childhood is short, so finding such a massive object so early in its evolution is a spectacular result," adds team member Gary Fuller from the University of Manchester, UK.

Another team member, Ana Duarte Cabral from the Laboratoire d'Astrophysique de Bordeaux, France, emphasises that "the ALMA observations reveal the spectacular details of the motions of the filamentary network of dust and gas, and show that a huge amount of gas is flowing into a central compact region". This strongly supports the theory of global collapse for the formation of massive stars, rather than fragmentation.

Zooming in on the birth of a monster star

These observations formed part of the Early Science phase of ALMA, and have made use of just a quarter of the full array of antennas. “We managed to get these very detailed observations using only a fraction of ALMA’s ultimate potential,” concludes Peretto. “ALMA will definitely revolutionise our knowledge of star formation, solving some current problems, and certainly raising new ones.”

Notes:

[1] Astronomers use the expression “massive stars” to mean those with roughly ten or more times the mass of the Sun. It refers to the star’s mass, not its size.

[2] This star formation region is forming many stars. The 500 solar mass core is the most massive of several.

More information:

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Southern Observatory (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

This research was presented in a paper entitled “Global collapse of molecular clouds as a formation mechanism for the most massive stars”, to appear in Astronomy & Astrophysics.

The team is composed of N. Peretto (CEA/AIM Paris Saclay, France; University of Cardiff, UK), G. A. Fuller (University of Manchester, UK; Jodrell Bank Centre for Astrophysics and UK ALMA Regional Centre Node), A. Duarte-Cabral (LAB, OASU, Université de Bordeaux, CNRS, France), A. Avison (University of Manchester, UK; UK ALMA Regional Centre node), P. Hennebelle (CEA/AIM Paris Saclay, France), J. E. Pineda (University of Manchester, UK; UK ALMA Regional Centre node; ESO, Garching, Germany), Ph. André (CEA/AIM Paris Saclay, France), S. Bontemps (LAB, OASU, Université de Bordeaux, CNRS, France), F. Motte (CEA/AIM Paris Saclay, France), N. Schneider (LAB, OASU, Université de Bordeaux, CNRS, France) and S. Molinari (INAF, Rome, Italy).

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/eso1331/eso1331a.pdf

Photos of the ALMA array: http://www.eso.org/public/images/archive/search/?adv=&subject_name=Atacama%20Large%20Millimeter/submillimeter%20Array

ESO/ALMA (ESO/NRAJ/NRAO)/NASA/Spitzer/JPL-Caltech/GLIMPSE/IAU and Sky & Telescope/Digitized Sky Survey 2. Acknowledgement: Davide De Martin/Video: ESO/Nick Risinger (skysurvey.org), DSS, ALMA(ESO/NAOJ/NRAO), NASA/JPL-Caltech/GLIMPSE. Music: movetwo.

Best regards, Orbiter.ch

Probing vegetation across the globe

ESA - Proba-V logo.

10 July 2013

 Proba-V first global map

The first global map of vegetation from the recently launched Proba-V has been unveiled, demonstrating that the minisatellite is on track to continue a 15-year legacy of global vegetation monitoring from space.

Proba-V is designed to map land cover and vegetation growth across the entire planet every two days. The data can also be used for day-by-day tracking of extreme weather, alerting authorities to crop failures, monitoring inland water resources and tracing the steady spread of deserts and deforestation.

Slightly larger than a washing machine, the miniature satellite was launched from French Guiana in the early hours of 7 May. Just over a week later, its Vegetation imager was switched on in time to capture its first image over France’s west coast along the Bay of Biscay.

First image

While still being commissioned, the satellite continued to acquire images that have been stitched together to give us the mission’s first, uncalibrated map of global vegetation – unveiled last week at the Probing Vegetation conference in Antwerp, Belgium.

“The results of these weeks of Proba-V commissioning give us confidence that the Vegetation users will not be disappointed and will benefit from the new higher performance Proba-V products,” noted Alberto Tobias, Head of ESA’s Systems, Software and Technology Department.

The commissioning phase includes a careful cross-calibration of the Vegetation imager with the previous generation of the instrument, operating on France’s Spot-5 satellite, to ensure data compatibility.

Proba-V satellite

The Spot-Vegetation mission, flown aboard both the Spot-4 and Spot-5 satellites, marked 15 years of service in May, but will come to an end after Proba-V takes over later this year. Achievements of the Vegetation imaging instruments were also highlighted at the conference.

Proba-V will also bridge the gap in vegetation monitoring between Spot-Vegetation and the future Sentinel-3 mission, being developed for Europe’s Global Monitoring for Environment and Security programme.

More information:

Proba-V: http://www.esa.int/Our_Activities/Observing_the_Earth/Proba-V

VITO: Proba-V: http://proba-v.vgt.vito.be/

Proba development & technology: http://www.esa.int/Our_Activities/Technology/Proba_Missions

GMES: http://www.esa.int/Our_Activities/Observing_the_Earth/GMES

Images, Text, Credits: ESA / P.Carril.

Greetings, Orbiter.ch

Astronauts Complete First of Two July Spacewalks

ISS - Expedition 36 Mission patch.

July 9, 2013

Two Expedition 36 astronauts wrapped up a successful 6-hour, 7-minute spacewalk at 2:09 p.m. EDT Tuesday, completing the first of two July excursions to prepare the International Space Station  for a new Russian module and perform additional installations on the station’s backbone.

"Grab Bag" of Tasks Performed During ISS Spacewalk

Flight Engineers Chris Cassidy of NASA and Luca Parmitano of the European Space Agency began the spacewalk at 8:02 a.m. as they switched their spacesuits to battery power.  After the two spacewalkers exited the hatch, Cassidy moved to the top of the Z1 truss to remove and replace a Space-to-Ground Transmitter Receiver Controller.  This unit, one of two that allows for two independent strings of Ku-band communication for video and data, failed in December 2012.

Image above: Flight Engineer Luca Parmitano rides Canadarm2 to an International Space Station worksite during Tuesday's Expedition 36 spacewalk. Image Credit: NASA TV.

In parallel to this, Parmitano headed out to the Express Logistics Carrier-2 on the starboard truss segment and retrieved two experiments that were part of the Materials International Space Station Experiment-8, or MISSE-8.  The Optical Reflector Materials Experiment III (ORMatE-III) and the Payload Experiment Container, which assessed the impacts of the space environment on materials and processor elements, are scheduled to return to Earth aboard the SpaceX-3 commercial cargo craft later this year.

Read more about MISSE-8: http://www.nasa.gov/mission_pages/station/research/experiments/72.html

While he was out on the on the starboard truss, Parmitano also photographed the Alpha Magnetic Spectrometer-02 (AMS-02) to provide the research team a visual assessment of the condition of this state-of-the-art particle physics detector.

Read more about AMS-02: http://www.nasa.gov/mission_pages/station/research/experiments/742.html

Cassidy meanwhile routed power cables to support the addition of the new Russian Multipurpose Laboratory Module scheduled to arrive at the station later this year. Cassidy routed cables from the Unity node to the interface between the Pressurized Mating Adapter-1 and the Zarya module. The station cosmonauts will complete that set up during a future spacewalk. The new module, known as Nauka, will serve as a research facility, docking port and airlock for future Russian spacewalks and will replace the Pirs docking compartment.

The two spacewalkers teamed back up to remove two Radiator Grapple Bars (RGBs) and install one on the port side truss and the other on the starboard side so they will be more strategically located. These RGBs, which are intended to aid in the removal and replacement of failed thermal radiators, were delivered to the station aboard SpaceX-2. While riding at the end of the station’s Canadarm2 robotic arm under the control of Flight Engineer Karen Nyberg, Parmitano transported the RGBs to the worksites where Cassidy bolted them down.

Image above: Flight Engineer Chris Cassidy routes cables for the Russian Multipurpose Laboratory Module during an Expedition 36 spacewalk outside the International Space Station. Image Credit: NASA TV.

As Parmitano rode the arm back from the starboard side to port, he used that opportunity to remove a failed camera assembly. The Mobile Base Camera Light Pan-Tilt Assembly, which failed back in May 2012 just before the arrival of the Japanese H-II Transfer Vehicle, was one of the prime viewing systems for monitoring visiting vehicles.  Mission managers plan to bring the assembly back to Earth for refurbishment and return it to the station later as a valid spare.

With those tasks complete and the RGBs installed, Cassidy began the installation of two Z1 truss Y-bypass jumpers to provide power redundancy and stability for critical station components. The bypass jumper installation will be completed during the July 16 spacewalk.  In conjunction with some cable reconfigurations completed earlier this year inside Unity, the two Y-bypass jumpers will allow the station team to quickly regain critical loads in the event of a loss of one of the external power modules without the need to commit to a spacewalk.

Image above: Flight Engineer Luca Parmitano is transported during the July 9 spacewalk by the International Space Station's Canadarm2 controlled by Flight Engineer Karen Nyberg. Image Credit: NASA TV.

Working briskly ahead of the planned timeline, Parmitano installed a multi-layer insulation cover to protect the docking interface of Pressurized Mating Adapter-2 mounted to the Harmony module.

The two spacewalkers then moved on to a couple of get-ahead tasks -- including the initial routing of cables from the Zarya module to Pressurized Mating Adapter-1 -- before moving back into the Quest airlock to end the spacewalk.

With the completion of his fifth career spacewalk, Cassidy now has a total of 29 hours, 42 minutes of total spacewalking time to his credit.  It was the first spacewalk for Parmitano and the first for an Italian. Cassidy and Parmitano are slated to head back out the Quest airlock on July 16 for another spacewalk to complete the Z1 Y-bypass jumper installation and route additional cables.

Tuesday's spacewalk  was the 170th in support of station assembly and maintenance, totaling 1,073 hours, 50 minutes.

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.

Best regards, Orbiter.ch

Ariane 6

ESA / Arianespace logos.

July 9, 2013

The baseline configuration of Ariane 6 selected by consensus on the basis of decisions taken by ESA's Ministerial Council of Novembr 2012.

In November 2012, European Ministers responsible for space, meeting in Naples, Italy, approved the start of preparatory activities for Europe’s next-generation Ariane 6 launch vehicle.

The objective of Ariane 6 is to maintain guaranteed autonomous access to space for Europe, while minimising exploitation costs and suppressing any support to exploitation.

Artist's view of Ariane 6

The performance requested for the new launch vehicle was 3–6.5 tonnes in equivalent geostationary transfer orbit (GTO), to cover both governmental and commercial needs. The general configuration retained was ‘PPH’ – indicating the sequence of stages using solid propulsion, solid propulsion and cryogenic propulsion.

Ministers also requested that the new launch vehicle exploits maximum commonalities with the cryogenic reignitable upper stage of Ariane 5 ME.

Ariane 6 animation

Process

Seven months after ESA’s Ministerial Council decision, the project team of ESA, supported by CNES, has endorsed the final concept proposed by industry for the vehicle that will become Europe’s workhorse for reaching space in the 2020s and beyond.

This concept was selected after six months of trade-off studies done by a ‘plateau projet’ integrating industrial teams (Astrium, Avio, Herakles and the participation of Safran, MT Aerospace and others) working under ESA contract, consistent with Ministerial decisions mentioned above.

The choice of configuration was made by consensus and based on the following main criteria: exploitation costs, time to market and development costs.

Ariane 6 will benefit from the advances by European industry in solid and cryogenic propulsion, structures, systems, avionics, ground segment and operations through the Ariane and Vega programmes.

Baseline configuration selected

The selected ‘Multi P linear’ concept is based on a lower ‘composite’ of four motors, each loaded with around 135 tonnes of solid propellant, providing also synergies with the Vega evolution perspectives. An "in-line" arrangement of three will serve as the first stage, while the fourth will be mounted above as the second stage.

‘Multi P linear’ concept

The third stage will be an adapted version of the Ariane 5 ME upper stage, equipped with the Vinci engine and specific propellant tanks.

The 5.4 m-diameter payload fairing will be able to accommodate the same volume of satellites as Ariane 5.

Steps to October 2013

The next step will be for ESA to consult with industry to gather competing ideas on key work packages of the new launch system. Industry will have maximum flexibility for meeting the requirements.

Consolidation of the current Phase A will take place at the Preliminary Requirements Review (PRR) in October 2013.

European launchers: powering Europe into space

Decisions taken by the ESA Council at Ministerial level in November 2012 are being implemented strictly and timely.

Related links:

Launcher strategy: http://www.esa.int/Our_Activities/Launchers/Launcher_strategy

Future Launchers Preparatory Programme: http://www.esa.int/Our_Activities/Launchers/FLPP_preparing_for_Europe_s_next-generation_launcher

International cooperation: http://www.esa.int/Our_Activities/Launchers/International_cooperation

Images, Videos, Text, Credits: ESA / D. Ducros / AOES Medialab.

Greetings, Orbiter.ch

Solar Impulse Across America 2013: From Washington D.C. to New York City

Solar Impulse - Across America 2013 patch.

July 7, 2013

Prototype Plane Completes Across America Mission Powered Only by Solar Energy

Image above: Across America 2013:Final leg from Washington DC. to New-York City. Landing. Solar Impulse / Merz / Rezo.ch.

Solar Impulse – the solar-powered airplane of Swiss pioneers Bertrand Piccard and André Borschberg – has successfully landed at New York’s John F. Kennedy International Airport setting a new milestone in the history of aviation: for the first time a plane capable of flying day and night powered exclusively by solar energy has crossed the USA from the West to the East Coasts without using a single drop of fuel.

Across America: Landing in New York JFK

André Borschberg, Solar Impulse Co-founder and CEO, landed Solar Impulse at JFK on Saturday, July 6 at 11:09 p.m. EDT, 3 hours earlier than planned because of a rip in the fabric on the lower side of the left wing. The flight took 18h 23min with a departure from Washington Dulles at 04:46 a.m. EDT on Saturday.

Flight Washington KIAD - New-York KJFK

- Pilot: André Borschberg, Co-Founder and CEO

- Take off : July 6th 04:46AM EDT (UTC-4)

- Landing: July 6th 11:09PM EDT (UTC-4)

- Flight duration: 18h23min

- Average ground speed: 27km/h (15 kts)

- Highest altitude reached: 3110 m (10 200 ft)

- Flight Distance: 495 km (~267 NM)

“This last leg was especially difficult due to the damage of the fabric on the left wing. It obliged the team to envisage all the possible scenarios, including bailing out over the Atlantic. But this type of problem is inherent to every experimental endeavor. In the end, this didn’t prevent us from succeeding in our Across America mission and provided an invaluable learning experience in preparation for the round-the-world tour in 2015,” said André Borschberg shortly after landing, adding “we extend our gratitude to all airport and government authorities whose precious support made this mission possible.”

Image above: Across America 2013:Final leg from Washington DC. to New-York City. Checking of the damages on the wing. Solar Impulse / Merz / Rezo.ch.

The arrival of Solar Impulse in New York City marks the culmination of its ambitious journey Across America, which started on May 3rd in San Francisco, California. The journey took a total of 105h 41min and 3511 miles flown at an average speed of 28.8 kt. Before reaching New York, Bertrand Piccard and André Borschberg alternately flew Solar Impulse to Phoenix, Dallas-Fort Worth, St. Louis, Cincinnati and Washington D.C. The plane stopped over in each of these cities giving the opportunity to the team to organize public viewings and political meetings with high level representatives such as Secretary of Energy Ernest Moniz, to promote clean technologies, energy efficiency and renewable energies.

Image above: Across America 2013:Final leg from Washington DC. to New-York City. A. Borschberg and B. Piccard just after the successful landing. Solar Impulse / Merz / Rezo.ch.

“Flying coast-to-coast has always been a mythical milestone full of challenges for aviation pioneers. During this journey, we had to find solutions for a lot of unforeseen situations, which obliged us to develop new skills and strategies. In doing so, we also pushed the boundaries of clean technologies and renewable energies to unprecedented levels,” said Dr. Bertrand Piccard, Solar Impulse Initiator, Chairman and pilot.

For more information about Solar Impulse, visit: http://www.solarimpulse.com/

Image (mentioned), Video, Text, Credit: Solar Impulse.

Best regards, Orbiter.ch