vendredi 8 juillet 2011

Last Space Shuttle mission launched












NASA - STS-135 Mission patch.

8 July 2011

 Last Space Shuttle mission launch

Space Shuttle Atlantis was launched today at 17:29 CEST (15:29 GMT) to the International Space Station on a mission that will end the multi-purpose spaceplane programme’s three-decade era of human spaceflight.

video
STS-135 Space Shuttle Launch

Atlantis will dock after about 2 days with the orbital outpost on Sunday at 17:09 CEST (15:09 GMT) and the four new astronaut arrivals will float into the Station about two hours later where currently the ISS Expedition 28 crew consisting of two American and one Japanese astronauts and 3 Russian cosmonauts permanently live and work in space.

Atlantis is carrying the Italian-built Raffaello pressurized logistics module filled with vital supplies and spares. On the journey down, it will return a range of items to Earth. Also all the samples from the on-board MELFI freezers will be returned to Earth in thermally conditioned state for analysis by the scientists.

Raffaello will be berthed at the Node-2 port on Monday and, after unloading its precious cargo, it will be detached again on Sunday 17 July and put back by the Space Station robotic arm into the Shuttle cargo bay.

Spacewalkers in aft flight deck windows of Atlantis in last May

Two of the Shuttle astronauts will make a spacewalk on Tuesday 12 July to recover a Station ammonia pump that recently failed. It will be returned to Earth for engineers to probe the causes.

Atlantis will leave the Station again on Monday 18 July at 07:59 CEST (05:59 GMT).

The final Shuttle landing at the Kennedy Space Center is planned for Wednesday 20 July at 13:06 CEST (11:06 GMT).

Follow online:

Follow the mission on NASA TV and read more about the Space Shuttle and Europe’s participation on ESA’s 'Tribute to the Space Shuttle' web pages:

NASA TV: http://www.nasa.gov/multimedia/nasatv/index.html

Tribute to the Space Shuttle: http://www.esa.int/Shuttle

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

Cheers, Orbiter.ch

Last Space Shuttle mission ready for launch












NASA - STS.135 Mission patch.

8 July 2011

If weather permits, history will be made this evening when Space Shuttle Atlantis ignites its engines and rises from the launch pad to begin the last flight of the programme. Twelve days later, the crew of four will steer the venerable space workhorse back to Earth and into retirement.

Across three decades, Space Shuttles Columbia, Challenger, Discovery, Atlantis and Endeavour have climbed towards space 134 times from the Florida coastline before this last mission, STS-135.

Atlantis is ready, but weather is iffy

The era saw high-flying successes and a chain of firsts but it was marred by the two tragic losses that led NASA to decide in 2003 to retire the spaceplane after completing assembly of the International Space Station.

Mission STS-134 was planned to end the series, but STS-135 was added to deliver a variety of supplies and major spare parts to sustain Station operations. In comparison, the remaining unmanned ferries are unable to loft large items.

Atlantis stood by for a potential rescue mission during Discovery’s last mission, so NASA decided to fly it once more to the Station with a minimal crew of four.

If there are problems, they can use the Station as a safe haven until they can return to Earth aboard Russia’s Soyuz spacecraft.

Launch on Friday

The 12-day STS-135 mission will be launched at 17:26 CEST (15:26 GMT), and on Sunday 10 July, Atlantis will dock with the Station, where currently the ISS Expedition 28 crew consisting of two American and one Japanese astronauts and 3 Russian cosmonauts permanently live and work in space.

STS-135 crew with Atlantis

The Italian-built Raffaello pressurized logistics module module will be berthed at the Node-2 port of the orbital outpost for the crew to unload its precious cargo and install various items for return.

Two ISS astronauts, Michael Fossum and Ron Garan will make a spacewalk on Tuesday 12 July to recover a Station ammonia pump that recently failed. It will be returned to Earth for engineers to probe the causes.

Raffaello will be returned to the Shuttle’s cargo bay on Sunday 17 July and Atlantis will leave the Station for the last time on Monday 18 July at 07:59 CEST (05:59 GMT).

The final Shuttle landing at the Kennedy Space Center is planned for Wednesday 20 July at 13:06 CEST (11:06 GMT).

During the mission, the Atlantis crew will also test tools and techniques for the robotic refuelling of satellites in space.

Follow online:

Follow the launch attempt on NASA TV on Friday afternoon and read more about the Space Shuttle and Europe’s participation on ESA’s 'Tribute to the Space Shuttle' web pages.

NASA TV: http://www.nasa.gov/multimedia/nasatv/index.html

Tribute to the Space Shuttle: http://www.esa.int/Shuttle

Images, Text, Credits: ESA / NASA / KSC.

Greetings, Orbiter.ch

jeudi 7 juillet 2011

Exploding stars can make good dust factories












ESA - HERSCHEL Mission patch.

7 July 2011

ESA’s Herschel space observatory has discovered that titanic stellar explosions can be excellent dust factories. In space, the dust mixes with gas to become the raw material for new stars, planets and, ultimately, life. This discovery may solve a mystery of the early Universe.

The discovery was made while Herschel was charting emission from cold dust in the Large Magellanic Cloud, a small galaxy near to the Milky Way. It is the perfect observatory for the job because cold dust radiates far-infrared light, the wavelengths Herschel is designed to detect.

Herschel saw a spot of light at the location of supernova 1987A, an exploding star first seen from Earth in February 1987, and the closest known supernova in the past 400 years.

Herschel and Hubble view of Supernova 1987A

Since then, astronomers have been studying the remains of the explosion as its blast wave expands into its surroundings.

Herschel’s images are the first clear-cut far-infrared observations of SN1987A. They reveal cold dust grains at about –250ºC, emitting more than 200 times the Sun’s energy.

“The supernova remnant was much brighter at infrared wavelengths than we were expecting,” says Mikako Matsuura, University College London, who is the lead author on the paper detailing these results.

The remnant’s brightness was used to estimate the amount of dust. Surprisingly, there turned out to be about a thousand times more dust than astronomers had thought a supernova was capable of producing – enough to make 200 000 planets the size of Earth.

The origin of dust in the Universe is of great interest. Its heavy atoms like carbon, silicon, oxygen and iron were not produced in the Big Bang and must have formed later.

Although they are only a minor part of the Universe and our Solar System, they are the main constituents of rocky planets like Earth and thus of life itself: many of the atoms we are made of were once part of the dust in the Universe.

Artist's impression of Herschel

However, it is not fully understood where this dust comes from, especially in the distant and thus young Universe, but now we have an indication.

The many old red giant stars in today’s Universe are thought to be the major dust producers, with the grains condensing like soot in a chimney as warm gases flow away from the star.

However, there were no such stars in the early Universe – yet we know there was already dust.

Now Herschel has shown that supernovas can produce enormous amounts of dust: the astronomers speculate that the dust condenses from the gaseous debris as it expands from the explosion and cools.

Since there were plenty of supernovas in the young Universe, this could help to explain the origin of dust seen at those times.

“These observations provide the first direct evidence that supernovas can produce the dust seen in young galaxies at great distance,” says Göran Pilbratt, ESA’s Herschel Project Scientist.

“It is a significant result and shows yet again the value of opening a unique window onto the Universe..”

Read more:

Observations: Seeing in infrared wavelengths: http://www.esa.int/esaSC/SEMS72T1VED_index_0.html

Why infrared astronomy is a hot topic: http://www.esa.int/esaSC/SEMX9PZO4HD_index_0.html

L2, the second Lagrangian Point: http://www.esa.int/esaSC/SEMO4QS1VED_index_0.html

This story in depth: http://sci.esa.int/jump.cfm?oid=48906

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

Images, Text, Credits: ESA / Herschel / PACS / SPIRE / NASA-JPL / Caltech / UCL / STScI and the Hubble Heritage Team (AURA / STScI / NASA / ESA) / ESA - C. Carreau.

Greetings, Orbiter.ch

mercredi 6 juillet 2011

Cassini Spacecraft Captures Images And Sounds Of Big Saturn Storm








NASA / ESA - Cassini Insider's Mission patch.

July 06, 2011

Scientists analyzing data from NASA's Cassini spacecraft now have the first-ever, up-close details of a Saturn storm that is eight times the surface area of Earth.

On Dec. 5, 2010, Cassini first detected the storm that has been raging ever since. It appears at approximately 35 degrees north latitude on Saturn. Pictures from Cassini's imaging cameras show the storm wrapping around the entire planet covering approximately 1.5 billion square miles (4 billion square kilometers).


Image above: The huge storm churning through the atmosphere in Saturn's northern hemisphere overtakes itself as it encircles the planet in this true-color view from NASA's Cassini spacecraft. Image credit: NASA / JPL-Caltech / SSI.

The storm is about 500 times larger than the biggest storm previously seen by Cassini during several months from 2009 to 2010. Scientists studied the sounds of the new storm's lightning strikes and analyzed images taken between December 2010 and February 2011. Data from Cassini's radio and plasma wave science instrument showed the lightning flash rate as much as 10 times more frequent than during other storms monitored since Cassini's arrival to Saturn in 2004. The data appear in a paper published this week in the journal Nature.

"Cassini shows us that Saturn is bipolar," said Andrew Ingersoll, an author of the study and a Cassini imaging team member at the California Institute of Technology in Pasadena, Calif. "Saturn is not like Earth and Jupiter, where storms are fairly frequent. Weather on Saturn appears to hum along placidly for years and then erupt violently. I'm excited we saw weather so spectacular on our watch."


Image above: These false-color images from NASA's Cassini spacecraft chronicle a day in the life of a huge storm that developed from a small spot that appeared 12 weeks earlier in Saturn's northern mid-latitudes. Image credit: NASA / JPL-Caltech / SSI.

At its most intense, the storm generated more than 10 lightning flashes per second. Even with millisecond resolution, the spacecraft's radio and plasma wave instrument had difficulty separating individual signals during the most intense period. Scientists created a sound file from data obtained on March 15 at a slightly lower intensity period.

Cassini has detected 10 lightning storms on Saturn since the spacecraft entered the planet’s orbit and its southern hemisphere was experiencing summer, with full solar illumination not shadowed by the rings. Those storms rolled through an area in the southern hemisphere dubbed "Storm Alley." But the sun's illumination on the hemispheres flipped around August 2009, when the northern hemisphere began experiencing spring.

"This storm is thrilling because it shows how shifting seasons and solar illumination can dramatically stir up the weather on Saturn," said Georg Fischer, the paper's lead author and a radio and plasma wave science team member at the Austrian Academy of Sciences in Graz. "We have been observing storms on Saturn for almost seven years, so tracking a storm so different from the others has put us at the edge of our seats."


Image above: NASA's Cassini spacecraft captures a composite near-true-color view of the huge storm churning through the atmosphere in Saturn's northern hemisphere. Image credit: NASA / JPL-Caltech / SSI.

The storm's results are the first activities of a new "Saturn Storm Watch" campaign. During this effort, Cassini looks at likely storm locations on Saturn in between its scheduled observations. On the same day that the radio and plasma wave instrument detected the first lightning, Cassini's cameras happened to be pointed at the right location as part of the campaign and captured an image of a small bright cloud.

Because analysis on that image was not completed immediately, Fischer sent out a notice to the worldwide amateur astronomy community to collect more images. A flood of amateur images helped scientists track the storm as it grew rapidly, wrapping around the planet by late January 2011.

The new details about this storm complement atmospheric disturbances described recently by scientists using Cassini's composite infrared spectrometer and the European Southern Observatory's Very Large Telescope. The storm is the biggest observed by spacecraft orbiting or flying by Saturn. NASA's Hubble Space Telescope captured images in 1990 of an equally large storm.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena manages the mission for the agency's Science Mission Directorate in Washington. The radio and plasma wave science team is based at the University of Iowa, Iowa City, where the instrument was built. The imaging team is based at the Space Science Institute in Boulder, Colo.

For images and an audio file of the storm, visit: http://www.nasa.gov/cassini

Listen to audio file: 

Lightning Strikes at Saturn: http://www.nasa.gov/mission_pages/cassini/whycassini/pia14310.html

Images, Text, Credits: NASA / JPL-Caltech / SSI.

Greetings, Orbiter.ch

Hydrogen Peroxide Found in Space












ESO - European Southern Observatory logo.

6 July 2011

 The Rho Ophiuchi star formation region, where hydrogen peroxide has been detected in space (annotated)

Molecules of hydrogen peroxide have been found for the first time in interstellar space. The discovery gives clues about the chemical link between two molecules critical for life: water and oxygen. On Earth, hydrogen peroxide plays a key role in the chemistry of water and ozone in our planet’s atmosphere, and is familiar for its use as a disinfectant or to bleach hair blonde. Now it has been detected in space by astronomers using the ESO-operated APEX telescope in Chile.

An international team of astronomers made the discovery with the Atacama Pathfinder Experiment telescope (APEX), situated on the 5000-metre-high Chajnantor plateau in the Chilean Andes. They observed a region in our galaxy close to the star Rho Ophiuchi, about 400 light-years away. The region contains very cold (around -250 degrees Celsius), dense clouds of cosmic gas and dust, in which new stars are being born. The clouds are mostly made of hydrogen, but contain traces of other chemicals, and are prime targets for astronomers hunting for molecules in space. Telescopes such as APEX, which make observations of light at millimetre- and submillimetre-wavelengths, are ideal for detecting the signals from these molecules.

The Rho Ophiuchi star formation region, where hydrogen peroxide has been detected in space

Now, the team has found the characteristic signature of light emitted by hydrogen peroxide, coming from part of the Rho Ophiuchi clouds.

“We were really excited to discover the signatures of hydrogen peroxide with APEX. We knew from laboratory experiments which wavelengths to look for, but the amount of hydrogen peroxide in the cloud is just one molecule for every ten billion hydrogen molecules, so the detection required very careful observations,” says Per Bergman, astronomer at Onsala Space Observatory in Sweden. Bergman is lead author of the study, which is published in the journal Astronomy & Astrophysics.

Hydrogen peroxide (H2O2) is a key molecule for both astronomers and chemists. Its formation is closely linked to two other familiar molecules, oxygen and water, which are critical for life. Because much of the water on our planet is thought to have originally formed in space, scientists are keen to understand how it is created [1].

The constellation Ophiuchus, showing the Rho Ophiuchi star formation region

Hydrogen peroxide is thought to form in space on the surfaces of cosmic dust grains — very fine particles similar to sand and soot — when hydrogen (H) is added to oxygen molecules (O2). A further reaction of the hydrogen peroxide with more hydrogen is one way to produce water (H2O). This new detection of hydrogen peroxide will therefore help astronomers better understand the formation of water in the Universe.

“We don’t understand yet how some of the most important molecules here on Earth are made in space. But our discovery of hydrogen peroxide with APEX seems to be showing us that cosmic dust is the missing ingredient in the process,” says Bérengère Parise, head of the Emmy Noether research group on star formation and astrochemistry at the Max-Planck Institute for Radio Astronomy in Germany, and a co-author of the paper.

To work out just how the origins of these important molecules are intertwined will need more observations of Rho Ophiuchi and other star-forming clouds with future telescopes such as the Atacama Large Millimeter/submillimeter Array (ALMA) — and help from chemists in laboratories on Earth.

APEX is a collaboration between the Max-Planck Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (OSO) and ESO. The telescope is operated by ESO.

Notes:

[1] The new discovery of hydrogen peroxide may also help astronomers understand another interstellar mystery: why oxygen molecules are so hard to find in space. It was only in 2007 that oxygen molecules were first discovered in space, by the satellite Odin.

More information:

This research is published in the journal Astronomy & Astrophysics.

The team is composed of P. Bergman (Onsala Space Observatory, Chalmers University of Technology, Onsala, Sweden), B. Parise (Max-Planck Institute for Radio Astronomy, Bonn, Germany), R. Liseau (Chalmers University of Technology, Onsala, Sweden), B. Larsson (Stockholm University, Sweden), H. Olofsson (Onsala Space Observatory, Chalmers University of Technology), K. M. Menten (Max-Planck Institute for Radio Astronomy) and R. Güsten (Max-Planck Institute for Radio Astronomy).

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

Links:

    Research paper (Astronomy & Astrophysics): http://www.aanda.org/10.1051/0004-6361/201117170

    About the APEX telescope, from ESO: http://www.eso.org/public/teles-instr/apex.html

    The APEX science website: http://www.apex-telescope.org/

    More on ALMA from ESO: http://www.eso.org/public/teles-instr/alma.html

    The Joint ALMA Observatory website: http://www.almaobservatory.org/

    The Max-Planck Institute for Radio Astronomy press release (English, German):
http://www.mpifr-bonn.mpg.de/public/pr/pr-h2o2-jul2011-en.html
http://www.mpifr-bonn.mpg.de/public/pr/pr-h2o2-jul2011-dt.html

    Chalmers press release (English, Swedish):
http://www.chalmers.se/en/news/Pages/Hydrogen-Peroxide-Found-in-Space.aspx
http://www.chalmers.se/sv/nyheter/Sidor/Vateperoxid-upptackt-i-rymden.aspx

Images, Text, Credits: ESO / S. Guisard / IAU and Sky & Telescope.

Best regards, Orbiter.ch

Eye of Gaia: billion-pixel camera to map Milky Way












ESA - Gaia Mission patch.

6 July 2011

The largest digital camera ever built for a space mission has been painstakingly mosaicked together from 106 separate electronic detectors. The resulting “billion-pixel array” will serve as the super-sensitive ‘eye’ of ESA’s Galaxy-mapping Gaia mission.

ESA’s Galaxy-mapping Gaia

While the naked human eye can see several thousand stars on a clear night, Gaia will map a billion stars within our own Milky Way Galaxy and its neighbours over the course of its five-year mission from 2013, charting their brightness and spectral characteristics along with their three-dimensional positions and motions.

In order to detect distant stars up to a million times fainter than the eye can see, Gaia will carry 106 charge coupled devices (CCDs), advanced versions of chips within standard digital cameras.

Gaia camera array

Developed for the mission by e2v Technologies of Chelmsford, UK, these rectangular detectors are a little smaller than a credit card, each one measuring 4.7x6 cm but thinner than a human hair.

The 0.5x1.0 m mosaic has been assembled at the Toulouse facility of Gaia prime contractor Astrium France.

Technicians spent much of May carefully fitting together each CCD package on the support structure, leaving only a 1 mm gap between them. Working in double shifts in strict cleanroom conditions, they added an average four CCDs per day, finally completing their task on 1 June.

“The mounting and precise alignment of the 106 CCDs is a key step in the assembly of the flight model focal plane assembly,” said Philippe Garé, ESA’s Gaia payload manager.

video
3-D view of Gaia's telescope elements and focal plane

The completed mosaic is arranged in seven rows of CCDs. The main array comprises 102 detectors dedicated to star detection. Four others check the image quality of each telescope and the stability of the 106.5º angle between the two telescopes that Gaia uses to obtain stereo views of stars.

In order to increase the sensitivity of its detectors, the spacecraft will maintain their temperature of –110º.

Gaia’s CCD support structure, like much of the rest of the spacecraft, is made of silicon carbide – a ceramic like material, extraordinarily resistant to deforming under temperature changes.

First synthesised as a diamond substitute, SiC has the advantage of low weight: the entire support structure with its detectors is only 20 kg.

Completed CCD array

Gaia will operate at the Earth–Sun L2 Lagrange point, above 1 million kilometers behind the earth, when looking from the sun, where Earth’s orbital motion balances out gravitational forces to form a stable point in space. As the spinning Gaia’s two telescopes sweep across the sky, the images of stars in each field of view will move across the focal plane array, divided into four fields variously dedicated to star mapping, position and motion, colour and intensity and spectrometry.

Scheduled for launch in 2013, Gaia’s three-dimensional star map will help to reveal the composition, formation and evolution of the Milky Way, sampling 1% of our Galaxy’s stars.

Gaia should also sample large numbers of other celestial bodies, from minor bodies in our own Solar System to more distant galaxies and quasars near the edge of the observable Universe.

Related links:

The Interactive Books of Gaia: http://sci2.esa.int/interactive/media/start.htm

This article in depth: http://sci.esa.int/jump.cfm?oid=48901

Gaia in-depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=26

Images, Video, Text, Credits: ESA / Astrium.

Greetings, Orbiter.ch

mardi 5 juillet 2011

Hubble makes its millionth observation












ESA - Hubble Space Telescope logo.

5 July 2011

Milestone observation used to search for water in an exoplanet’s atmosphere

Transiting exoplanet HAT-P-7b (artist's impression)

The NASA/ESA Hubble Space Telescope has made its millionth observation since its launch 21 years ago. The telescope was used to search for the chemical signature of water in the atmosphere of planet HAT-P-7b [1], a gas giant larger than Jupiter which orbits the star HAT-P-7.

Alvaro Gimenez, head of science and robotic exploration for the European Space Agency said: “With a million observations and many thousands of scientific papers to its name, Hubble is one of the most productive scientific instruments ever built. As well as changing our view of the Universe with its stunning imagery, Hubble has revolutionised whole areas of science. Thanks to ESA’s participation in the Hubble project, the European scientific community is playing a starring role in these achievements.”

Although Hubble is perhaps best known for its detailed images of astronomical objects, the millionth observation was actually made with a spectrograph. Spectroscopy is the technique of splitting light into its component colours. The gases present in a planet’s atmosphere leave a fingerprint in the form of the distinctive colour patterns that different gases absorb. Analysing this data can give precise measurements of which elements are present in an object too distant to ever be visited by a space probe.

“We are looking for the spectral signature of water vapour. This is an extremely precise observation and it will take months of analysis before we have an answer,” explains Drake Deming of the University of Maryland and NASA’s Goddard Space Flight Center, who designed Hubble’s millionth observation. “Hubble has demonstrated that it is ideally suited for characterising the atmospheres of exoplanets and we are excited to see what this latest targeted world will reveal.”

Hubble was launched on the space shuttle Discovery on 24 April 1990. In the 21 years that have followed, the telescope has collected over 50 terabytes of data, enough to fill more than 10 000 DVDs. The huge and varied library of data it has produced in the course of these million observations is made freely available to scientists and the public through an online archive.

European astronomers are guaranteed 15% of observing time on the telescope, but have consistently been awarded more through open competition. In the next round of Hubble observations, teams led by European scientists have been awarded more than 20% of the available time.

Hubble’s million observations include every observation of astronomical targets since its launch in addition to observations used to calibrate its suite of instruments. Hubble made the millionth observation using its Wide Field Camera 3, a visible- and infrared-light imager with an on-board spectrometer. It was installed by astronauts during the Hubble Servicing Mission 4 in May 2009.

Notes:

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

[1] The planet’s name derives from the telescope that discovered it. HATnet is the Hungarian Automated Telescope Network, which searches for exoplanets using a series of small, robotic telescopes that observe the dimming of a star’s light as a planet passes in front of it (this is known as the transiting method).

More Information

The millionth observation was carried out under observing program 12181, “The Atmospheric Structure of Giant Hot Exoplanets”. The principal investigator (scientific lead) on this project is Drake Deming.

Links:

    NASA release: http://hubblesite.org/news/2011/22

    Proposal for observing program 12181: http://www.stsci.edu/observing/phase2-public/12181.pro


Also see our announcements on eso.org: http://www.eso.org/public/announcements/

Images, Text, Credits: NASA / ESA and G. Bacon (STScI).

Cheers, Orbiter.ch

Pioneering ERS environment satellite retires











 ESA - ERS-2 satellite logo.

5 July 2011

After 16 years spent gathering a wealth of data that has revolutionised our understanding of Earth, ESA's veteran ERS-2 satellite is being retired. This pioneering mission has not only advanced science, but also forged the technologies we now rely on for monitoring our planet.

ERS-2 was launched in 1995, following its sister, the first European Remote Sensing satellite, which was launched four years earlier.

Carrying suites of sophisticated instruments to study the complexities of the atmosphere, land, oceans and polar ice, these two missions were the most advanced of their time, putting Europe firmly at the forefront of Earth observation.

ERS-2 captures Etna 'breathing' 1992–2001

The twin satellites were identical, apart from ERS-2's additional instrument to monitor ozone in the atmosphere. Both exceeded their design lifetime by far, together delivering a 20-year stream of continuous data.

In 2000, ERS-1 unexpectedly stopped working and now it is time to bid farewell to ERS-2 before it succumbs to a similar fate.

To avoid ERS-2 ending up as a piece of space debris, ESA will take the satellite out of service by bringing it down to a lower orbit while there is still sufficient fuel to make the careful manoeuvres.

ERS-2 in the cleanroom

The decision to retire ERS-2 was not taken lightly, but after orbiting Earth almost 85 000 times – travelling 3.8 billion km – the risk that the satellite could lose power at any time is clearly high.

The deorbiting procedure will be carried out over a number of weeks by spacecraft operators and flight dynamics experts at ESA's European Space Operations Centre in Germany.

Starting on 6 July, a series of thruster burns will gradually lower the satellite's orbit from its current altitude of 800 km to about 550 km, where the risk of collision is minimal. Eventually, ERS-2 will enter Earth's atmosphere and burn up.

Its destruction will occur within 25 years, in accordance with European Code of Conduct on Space Debris Mitigation.

ERS-2 has been delivering data right to the end. In one of its last operations, the satellite was placed in an orbit that allowed it to capture radar images every three days of some of Earth's most rapidly changing features.

Digital elevation model Bachu, China
  
Over their lifetimes, the missions have achieved many outstanding results. With thousands of research projects and published scientific papers based on ERS data, it is difficult to list them all.

Carrying the first spaceborne civil radar, the missions offered a new perspective of Earth.

In particular, by exploiting the process of synthetic aperture radar interferometry we have been able to monitor how the ground moves during events like the earthquake that recently devastated Japan. A similar technique is also used to generate digital elevation models.

Moreover, these data build up a long-term archive so that changes over time can be carefully monitored.

The radiometer has provided precise maps of global sea-surface temperature, leading to novel observations of the 1997 El Niňo, and the radar altimeter provided new information on sea level, a major concern linked to climate change.

Sea-surface temperature from ERS

In addition, the Global Ozone Monitoring Experiment (GOME) on ERS-2 provided insight into the depletion of stratospheric ozone over Antarctica.

GOME was the longest serving ozone monitor in the world, with its success leading to a string of similar satellite sensors.

The continual improvement of data processing since ERS-2 was first placed in orbit has meant that a wealth of other information on atmospheric gases such as nitrogen dioxide could also be gleaned from GOME.

While the observations from ERS have been used in a multitude of application areas, they also form a valuable contribution to a long-term data archive to understand how Earth works as a system and the impact climate change is having.

Ozone hole over Antarctica

It is difficult to overstate the value that the ERS missions have brought to science, but just as important has been the technological excellence the instruments have demonstrated.

These various technologies live on in successor missions such as ESA's Envisat, the Earth Explorers and the Sentinels for Europe's Global Monitoring for Environment and Security programme, as well as in many other national satellite missions.

In essence, ERS provided the scientific and technical heritage for Europe to continue monitoring our planet from space.

Related missions:

ERS overview: http://www.esa.int/esaEO/SEMGWH2VQUD_index_0_m.html

Space Operations & Situational Awareness: http://www.esa.int/SPECIALS/Operations/index.html

Images, Text, Credits: ESA/ JPL / P. Lundgren / DLR.

Best regards, Orbiter.ch

lundi 4 juillet 2011

ESA Tribute to the Space Shuttle














NASA - 30 Years Space Shuttle Program patch / NASA - Space Shuttle patch.

4 July 2011

The Space Shuttle will be launched 8 July on its last mission, bringing three decades of flights of this unique spaceplane to a close. ESA’s new website highlights this era and its important role in European space endeavours.

The boxy black and white craft is the queen of technological marvels from the late 20th century. From its first launch in 1981 the Space Shuttle has been the way to fly to space for many of humankind.

First launch of Atlantis

It has transformed spaceflight: it dispatched and partially even returned many satellites and deep-space probes, it helped to end the Cold War by docking with Russia’s Mir space station and it made assembly of the International Space Station possible.

Impressively, the Hubble Space Telescope was delivered into orbit, repaired and maintained by Shuttle on five missions.

With some 2.5 million moving parts, the orbiter with three main engines fuelled from the huge external tank, and the complementary twin solid rocket boosters form a package that is perhaps the most complex technological system ever built.

Europe and Space Shuttle

Europe was involved closely with the Space Shuttle from the beginning. NASA’s invitation in 1969 to participate in the post-Apollo Programme led Europe in 1972 to agree to develop a reusable pressurised laboratory module as an integral element of the US Space Transportation System.

Named ‘Spacelab’, it was sized for the Shuttle’s roomy cargo bay. Since it was modular and reusable, the composition of the laboratory was tailored to each mission.

Spacelab: European participation in Space Shuttle

This ESA-NASA cooperation meant that European astronauts flew on the Shuttle as the first non-US crewmembers. Beginning with the flight of ESA’s Ulf Merbold in 1983 on STS-9 the first Spacelab mission, 24 Europeans have flown on 25 Shuttle missions. The last was Roberto Vittori, on the craft’s penultimate flight last May.

Europe’s Columbus laboratory module was delivered by the Shuttle to the International Space Station, like the other European-built ISS infrastructure elements which provide a major portion of the habitable environment.

STS-135: important extra flight

NASA decided in 2003 to retire the Shuttle after completing the Space Station assembly, but last year another flight was added to deliver a variety of supplies and major spare parts to sustain Station operations. This Shuttle flight will also carry another time the Italian-built Multi-Purpose Logistics Module (MPLM) which has been instrumental namely for deploying ISS research racks.

The Shuttle fleet’s retirement will restrict cargo transport capacity and some spares cannot be delivered by the remaining unmanned ferries.

STS-135 crew with Atlantis

The 12-day STS-135 mission will be launched on Friday 8 July at 17:26 CEST (15:26 GMT). Shuttle Atlantis will attach the MPLM Raffaello temporarily to Node 2 port of the orbital outpost for the crew to unload its precious cargo and to take over also various download items.

Two of the four crewmembers will make one spacewalk to recover a Station ammonia pump that recently failed. It will be returned to Earth for engineers to understand the problem.

Atlantis will also fly the Robotic Refuelling Mission, an experiment to test the tools and techniques for the robotic refuelling of satellites in space.


Tribute to Space Shuttle

To celebrate the Space Shuttle and tell the stories of Europe’s fliers, ESA has today opened the dedicated site ‘Tribute to the Space Shuttle’: http://www.esa.int/Shuttle

To access the site, NASA: Space Shuttle: http://www.nasa.gov/mission_pages/shuttle/flyout/index.html

Images, Text, Credits: ESA / NASA / KSC.

Greetings and happy National Day for all Americans, Orbiter.ch