vendredi 26 août 2011
NASA - ESA Cassini "Insider's" Mission logo.
August 26, 2011
NASA's Cassini spacecraft captured new views of Saturn's oddly shaped moon Hyperion during its encounter with this cratered body on Thursday, Aug. 25. Raw images were acquired as the spacecraft flew past the moon at a distance of about 15,500 miles (25,000 kilometers), making this the second closest encounter.
Image above: NASA's Cassini spacecraft obtained this unprocessed image of Saturn's moon Hyperion on Aug. 25, 2011. Image credit: NASA / JPL-Caltech / Space Science Institute.
Hyperion is a small moon -- just 168 miles (270 kilometers) across. It has an irregular shape and surface appearance, and it rotates chaotically as it tumbles along in orbit. This odd rotation prevented scientists from predicting exactly what terrain the spacecraft's cameras would image during this flyby.
Image above: Side view taken by NASA's Cassini spacecraft of Saturn's moon Hyperion. Image credit: NASA / JPL-Caltech / Space Science Institute.
However, this flyby's closeness has likely allowed Cassini's cameras to map new territory. At the very least, it will help scientists improve color measurements of the moon. It will also help them determine how the moon's brightness changes as lighting and viewing conditions change, which can provide insight into the texture of the surface. The color measurements provide additional information about different materials on the moon's deeply pitted surface.
Image above: Closeup view of Hyperion taken by NASA's Cassini spacecraft. Image credit: NASA / JPL-Caltech / Space Science Institute.
The latest raw images of Hyperion are online at: http://saturn.jpl.nasa.gov/photos/raw/
Cassini's closest encounter with Hyperion was on September 26, 2005, when the spacecraft flew approximately 310 miles (500 kilometers) above the moon's surface.
Cassini's next flyby of Hyperion will be on Sept. 16, 2011, when it passes the tumbling moon at a distance of about 36,000 miles (58,000 kilometers).
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission, visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov
Images (mentioned), Text, Credits: NASA / JPL / Rosemary Sullivant.
Publié par Orbiter.ch à 15:40
ESA - ATV-3 Edoardo Amaldi Mission patch.
26 August 2011
cargo carrier to the International Space Station, has completed its first long voyage – sailing across the Atlantic. It is now at Europe’s Spaceport in Kourou, French Guiana to be prepared for launch early next year.
With only a few months since the end of the ATV-2 mission, the ESA teams in Europe and Kourou are getting into high gear with the next craft: ATV Edoardo Amaldi.
Unloading in Kourou harbour
Involving some 2000 highly skilled engineers across Europe, ATV-3 was reviewed and qualified in July by the ESA and EADS teams in Bremen, Germany for shipping to Kourou.
The review is of importance because, once the ATV is in Kourou, any major changes may affect the schedule.
ATV-3 interior during review
MN Toucan, a French cargo ship used normally by Arianespace to transport Ariane rocket elements, steamed from Bremerhaven on 6 August.
After sailing across the Atlantic for 13 days, it arrived early this week to hold position near Devil’s Island off the coast of French Guiana to wait for a favourable tide.
Yesterday, the ship docked in Kourou harbour and unloading began.
Image above: ATV-3 containers on the cargo deck of the French cargo ship MN Toucan during the 13-day voyage from Bremerhaven to Kourou.
Shipped in sections in several hermetically sealed containers, ATV-3 will be reassembled and tested before cargo will be inserted and it is fuelled for its mission.
The launch campaign is scripted in great detail and spans 180 working days.
MN Toucan leaving Bremen harbour
According to current planning, Edoardo Amaldi will carry about two tonnes of dry cargo, 285 kg of water and more than three tonnes of propellants.
ATV is the biggest cargo carrier servicing the Space Station and a vital element of ISS logistics.
ATV approaching Space Station
ATV - Automated Transfer Vehicle: http://www.esa.int/SPECIALS/ATV/index.html
ATV blog: http://blogs.esa.int/atv
ATV Factsheet: http://esamultimedia.esa.int/docs/ATV/Fact_ATV_cropmarks_EN.pdf
Space pioneers: Edoardo Amaldi: http://www.esa.int/SPECIALS/Space_Year_2007/SEMT5D0P0WF_0.html
Images, Text, Credits: ESA / D.Ducros.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 05:51
jeudi 25 août 2011
ESA - PROBA-2 Mission logo.
25 August 2011
Sometimes all it takes is fresh air to get a new lease of life. ESA’s Proba-2 microsatellite is a good example: an influx of nitrogen has replenished its fuel tank, in the process demonstrating a whole new space technology.
On 16 August a telecommand was sent from ESA’s Redu ground station in Belgium to boost the gases in Proba-2’s unusual ‘resistojet’ engine.
Used to maintain the microsatellite’s orbit at 600 km altitude, this experimental engine runs on xenon gas heated before ejection to provide added thrust.
The command added nitrogen gas to the fuel tank, bringing its pressure close to its launch level.
“What makes this repressurisation unique is that the added gas was not stored in a pressurised state but produced from a solid material at room temperature, the first of four ‘cool-gas generators’ on Proba-2,” explained Laurens van Vliet of Dutch research organisation TNO, which developed the technology.
“Nitrogen, like xenon, is an inert, non-reactive gas, so the resistojet can work just as well with a xenon–nitrogen mixture.”
The bottle-shaped cool-gas generators are filled with a rigid solid material that, once triggered, produces more than 250 times its own volume in pure nitrogen gas.
“The generators are a huge step forward because they can be stored without pressure with no danger of leaking, and require no maintenance,” added Berry Sanders of TNO. “Proba’s generators had not been touched in six years.
“This is very different to standard systems with gas under pressure, which are much more complex and need regular checking and maintenance.”
The other three generators will be used later in Proba-2’s orbital lifetime.
Integrating the cool-gas generators
TNO designed the Proba-2 cool-gas experiment in close cooperation with Netherlands-based Bradford Engineering, responsible for constructing it. The resistojet design came from UK company Surrey Satellite Technology Ltd while the experiment was integrated with the satellite by Belgium's QinetiQ Space.
The technology had been fast-tracked for space by the Dutch National Space Office as part of ESA’s General Support Technology Programme, supporting the development of promising prototypes into flight-ready hardware.
Proba-2 fuel tank telemetry
“With this test the technology has been ‘space-proven’, such demonstrations being one of the main goals of the Proba-2 mission,” concluded Mr Sanders.
It now has many other potential uses in space, including propulsion systems, oxygen production for astronauts and inflatable structures such as antennas, booms, landing airbags and full-sized habitat modules.
TNO team celebrate success
Proba-2 is the latest in ESA’s Project for Onboard Autonomy series of satellites, dedicated to the in-orbit demonstration of innovative technologies.
Proba-2 was launched on 2 November 2009. Less than a cubic metre in volume, it carries a total of 17 new technologies and four science payloads focused on the Sun and space weather.
Proba-2: science payloads: http://www.esa.int/SPECIALS/Proba/SEMSD5ZVNUF_0.html
Proba-2: technology demonstrations: http://www.esa.int/SPECIALS/Proba/SEMZC5ZVNUF_0.html
About the General Support Technology Programme (GSTP): http://www.esa.int/SPECIALS/Technology/SEMEU4WPXPF_0.html
TNO website: http://www.tno.nl/groep.cfm?context=overtno&content=magazines&laag1=37&item_id=70&Taal=2
Bradford Engineering: http://www.bradford-space.com/cms/
Surrey Satellite Technolgy Limited: http://www.sstl.co.uk/
Qinetiq Space (B): http://www.qinetiq.com/home_qinetiq_space_nv.html
Images, Text, Credits: ESA / Pierre Carril / TNO.
Publié par Orbiter.ch à 04:07
mercredi 24 août 2011
Mission Control Moscow reported an abnormal situation from the Progress 44 cargo craft that launched on time at 9 a.m. EDT today.
The Progress-M-12M blasts off from the launch pad at the Baikonour cosmodrome
Progress 44 launched from the Baikonur Cosmodrome into a cloudless sky at 7 p.m. Kazakhstan time bound for the International Space Station and a docking on Friday. At the time of launch, the space station was flying 230 miles over Equatorial Guinea on the west coast of Africa. The spacecraft is carrying 2.9 tons of food, fuel and supplies for the space station.
Progress M-12M 44P Launch - Failure
But, 5 minutes and 50 seconds after launch, Mission Control Houston received a report of an "off-nominal situation" during the rocket's third and final stage.
The unmanned Russian cargo spacecraft Progress has crashed in eastern Siberia after failing to reach its target orbit.
Progress M cargo spacecraft
Emergency with the carrier rocket "Soyuz-U" and not removal of cargo vehicle "Progress M-12M" on the target orbit will not affect the life support crews 28/29 International Space Station expeditions. Availability of food, water and life support systems allow for the functioning of the crew for a long period.
To investigate the reasons for this situation, a commission from among the Russian Space Agency and the organizations of the rocket-space industry.
Images, Video, Text, Credit: Press Service of the Russian Space Agency (Roscosmo PAO) / AFP, Getty / Orbiter.ch.
Publié par Orbiter.ch à 15:43
NASA - SWIFT Mission patch.
Aug. 24, 2011
Two studies appearing in the Aug. 25 issue of the journal Nature provide new insights into a cosmic accident that has been streaming X-rays toward Earth since late March. NASA's Swift satellite first alerted astronomers to intense and unusual high-energy flares from the new source in the constellation Draco.
Video above: On March 28, 2011, NASA's Swift detected intense X-ray flares thought to be caused by a black hole devouring a star. In one model, illustrated here, a sun-like star on an eccentric orbit plunges too close to its galaxy's central black hole. About half of the star's mass feeds an accretion disk around the black hole, which in turn powers a particle jet that beams radiation toward Earth. Video credit: NASA / Goddard Space Flight Center.
"Incredibly, this source is still producing X-rays and may remain bright enough for Swift to observe into next year," said David Burrows, professor of astronomy at Penn State University and lead scientist for the mission's X-Ray Telescope instrument. "It behaves unlike anything we've seen before."
Astronomers soon realized the source, known as Swift J1644+57, was the result of a truly extraordinary event -- the awakening of a distant galaxy's dormant black hole as it shredded and consumed a star. The galaxy is so far away, it took the light from the event approximately 3.9 billion years to reach Earth.
Burrows' study included NASA scientists. It highlights the X- and gamma-ray observations from Swift and other detectors, including the Japan-led Monitor of All-sky X-ray Image (MAXI) instrument aboard the International Space Station.
Image above: Positions from Swift's XRT constrained the source to a small patch of sky that contains a faint galaxy known to be 3.9 billion light-years away. But to link the Swift event to the galaxy required observations at radio wavelengths, which showed that the galaxy's center contained a brightening radio source. Analysis of that source using the Expanded Very Large Array and Very Long Baseline Interferometry (VLBI) shows that it is still expanding at more than half the speed of light. Credit: NRAO / CfA / Zauderer et al.
The second study was led by Ashley Zauderer, a post-doctoral fellow at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. It examines the unprecedented outburst through observations from numerous ground-based radio observatories, including the National Radio Astronomy Observatory's Expanded Very Large Array (EVLA) near Socorro, N.M.
Most galaxies, including our own, possess a central supersized black hole weighing millions of times the sun's mass. According to the new studies, the black hole in the galaxy hosting Swift J1644+57 may be twice the mass of the four-million-solar-mass black hole in the center of the Milky Way galaxy. As a star falls toward a black hole, it is ripped apart by intense tides. The gas is corralled into a disk that swirls around the black hole and becomes rapidly heated to temperatures of millions of degrees.
Image above: Swift's X-Ray Telescope continues to record high-energy flares from Swift J1644+57 more than three months after the source's first appearance. Astronomers believe that this behavior represents the slow depletion of gas in an accretion disk around a supermassive black hole. The first flares from the source likely coincided with the disk's creation, thought to have occurred when a star wandering too close to the black hole was torn apart. Credit: NASA / Swift / Penn State.
The innermost gas in the disk spirals toward the black hole, where rapid motion and magnetism create dual, oppositely directed "funnels" through which some particles may escape. Jets driving matter at velocities greater than 90 percent the speed of light form along the black hole's spin axis. In the case of Swift J1644+57, one of these jets happened to point straight at Earth.
"The radio emission occurs when the outgoing jet slams into the interstellar environment," Zauderer explained. "By contrast, the X-rays arise much closer to the black hole, likely near the base of the jet."
Images from Swift's Ultraviolet/Optical (white, purple) and X-Ray telescopes (yellow and red) were combined to make this view of Swift J1644+57. Evidence of the flares is seen only in the X-ray image, which is a 3.4-hour exposure taken on March 28, 2011. Credit: NASA / Swift / Stefan Immler.
Theoretical studies of tidally disrupted stars suggested they would appear as flares at optical and ultraviolet energies. The brightness and energy of a black hole's jet is greatly enhanced when viewed head-on. The phenomenon, called relativistic beaming, explains why Swift J1644+57 was seen at X-ray energies and appeared so strikingly luminous.
When first detected March 28, the flares were initially assumed to signal a gamma-ray burst, one of the nearly daily short blasts of high-energy radiation often associated with the death of a massive star and the birth of a black hole in the distant universe. But as the emission continued to brighten and flare, astronomers realized that the most plausible explanation was the tidal disruption of a sun-like star seen as beamed emission.
By March 30, EVLA observations by Zauderer's team showed a brightening radio source centered on a faint galaxy near Swift's position for the X-ray flares. These data provided the first conclusive evidence that the galaxy, the radio source and the Swift event were linked.
This illustration steps through the events that scientists think likely resulted in Swift J1644+57. Credit: NASA / Goddard Space Flight Center / Swift.
"Our observations show that the radio-emitting region is still expanding at more than half the speed of light," said Edo Berger, an associate professor of astrophysics at Harvard and a coauthor of the radio paper. "By tracking this expansion backward in time, we can confirm that the outflow formed at the same time as the Swift X-ray source."
Swift, launched in November 2004, is managed by NASA's Goddard Space Flight Center in Greenbelt, Md. It is operated in collaboration with Penn State, the Los Alamos National Laboratory in N.M. and Orbital Sciences Corp., in Dulles, Va., with international collaborators in the U.K., Italy, Germany and Japan. MAXI is operated by the Japan Aerospace Exploration Agency as an external experiment attached to the Kibo module of the space station. For images and animations related to the studies, visit: http://www.nasa.gov/swift
Images (mentioned), Video (mentioned), Text, Credit: NASA / Trent J. Perrotto / Lynn Chandler / Goddard Space Flight Center / Francis Reddy.
Publié par Orbiter.ch à 14:30
ESO - European Southern Observatory logo.
24 August 2011
VLT looks into The Eyes of the Virgin
ESO’s Very Large Telescope has taken a striking image of a beautiful yet peculiar pair of galaxies nicknamed The Eyes. The larger of these, NGC 4438, was once a spiral galaxy but has become badly deformed by collisions with other galaxies in the last few hundred million years. This picture is the first to come out of ESO’s Cosmic Gems programme, an initiative in which ESO has granted dedicated observing time for outreach purposes.
The Eyes are about 50 million light-years away in the constellation of Virgo (The Virgin) and are some 100 000 light-years apart. The nickname comes from the apparent similarity between the cores of this pair of galaxies — two white ovals that resemble a pair of eyes glowing in the dark when seen in a moderate-sized telescope.
But although the centres of these two galaxies look similar, their outskirts could not be more different. The galaxy in the lower right, known as NGC 4435, is compact and seems to be almost devoid of gas and dust. In contrast, in the large galaxy in the upper left (NGC 4438) a lane of obscuring dust is visible just below its nucleus, young stars can be seen left of its centre, and gas extends at least up to the edges of the image.
The Eyes in the constellation of Virgo
The contents of NGC 4438 have been stripped out by a violent process: a collision with another galaxy. This clash has distorted the galaxy’s spiral shape, much as could happen to the Milky Way when it collides with its neighbouring galaxy Andromeda in three or four billion years.
NGC 4435 could be the culprit. Some astronomers believe that the damage caused to NGC 4438 resulted from an approach between the two galaxies to within about 16 000 light-years that happened some 100 million years ago. But while the larger galaxy was damaged, the smaller one was significantly more affected by the collision. Gravitational tides from this clash are probably responsible for ripping away the contents of NGC 4438, and for reducing NGC 4435’s mass and removing most of its gas and dust.
Another possibility is that the giant elliptical galaxy Messier 86, further away from The Eyes and not visible in this image, was responsible for the damage caused to NGC 4438. Recent observations have found filaments of ionised hydrogen gas connecting the two large galaxies, indicating that they may have collided in the past.
The elliptical galaxy Messier 86 and The Eyes belong to the Virgo Cluster, a very rich grouping of galaxies. In such close quarters, galaxy collisions are fairly frequent, so perhaps NGC 4438 suffered from encounters with both NGC 4435 and Messier 86.
This picture is the first to be produced as part of the ESO Cosmic Gems programme. This is a new initiative to produce astronomical images for educational and public outreach purposes. The programme mainly makes use of time when the sky conditions are not suitable for science observations to take pictures of interesting, intriguing or visually attractive objects. The data are also made available to professional astronomers through ESO’s science archive.
Zooming in on The Eyes
In this case, although there were some clouds, the atmosphere was exceptionally stable, which allowed very sharp details to be revealed in this image taken using the VLT’s FORS2  instrument. Light passing through two different filters was used: red (coloured red) and green-yellow (coloured blue), and the exposure times were 1800 seconds and 1980 seconds, respectively.
 FORS2 is the visual and near ultraviolet FOcal Reducer and low dispersion Spectrograph for the VLT. It is installed on the VLT’s Unit Telescope 1.
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”.
ESO’s Cosmic Gems Programme: http://www.eso.org/public/outreach/gems.html
Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/
Images, Text, Credits: ESO / Gems project / IAU and Sky & Telescope / Richard Hook / Olivier R. Hainaut / Lars Lindberg Christensen / Video: ESO / A. Fujii and Digitized Sky Survey 2. Music: John Dyson (from the album Moonwind).
Best regards, Orbiter.ch
Publié par Orbiter.ch à 05:47
mardi 23 août 2011
NASA - WISE Mission patch labeled.
Aug. 23, 2011
Scientists using data from NASA's Wide-field Infrared Survey Explorer (WISE) have discovered the coldest class of star-like bodies, with temperatures as cool as the human body.
Astronomers hunted these dark orbs, termed Y dwarfs, for more than a decade without success. When viewed with a visible-light telescope, they are nearly impossible to see. WISE's infrared vision allowed the telescope to finally spot the faint glow of six Y dwarfs relatively close to our sun, within a distance of about 40 light-years.
This artist's conception illustrates what a "Y dwarf" might look like. Y dwarfs are the coldest star-like bodies known, with temperatures that can be even cooler than the human body. Image credit: NASA / JPL-Caltech.
"WISE scanned the entire sky for these and other objects, and was able to spot their feeble light with its highly sensitive infrared vision," said Jon Morse, Astrophysics Division director at NASA Headquarters in Washington. "They are 5,000 times brighter at the longer infrared wavelengths WISE observed from space than those observable from the ground."
The Y's are the coldest members of the brown dwarf family. Brown dwarfs are sometimes referred to as "failed" stars. They are too low in mass to fuse atoms at their cores and thus don't burn with the fires that keep stars like our sun shining steadily for billions of years. Instead, these objects cool and fade with time, until what little light they do emit is at infrared wavelengths.
Astronomers study brown dwarfs to better understand how stars form and understand the atmospheres of planets beyond our solar system. The atmospheres of brown dwarfs are similar to those of gas giant planets like Jupiter, but they are easier to observe because they are alone in space, away from the blinding light of a parent star.
NASA's Wide-field Infrared Survey Explorer, or WISE, has uncovered the coldest brown dwarf known so far (green dot in very center of this infrared image). Image credit: NASA / JPL-Caltech / UCLA.
So far, WISE data have revealed 100 new brown dwarfs. More discoveries are expected as scientists continue to examine the enormous quantity of data from WISE.
The telescope performed the most advanced survey of the sky at infrared wavelengths to date, from Jan. 2010 to Feb. 2011, scanning the entire sky about 1.5 times.
Of the 100 brown dwarfs, six are classified as cool Y's. One of the Y dwarfs, called WISE 1828+2650, is the record holder for the coldest brown dwarf with an estimated atmospheric temperature cooler than room temperature, or less than 80 degrees Fahrenheit (25 degrees Celsius).
"The brown dwarfs we were turning up before this discovery were more like the temperature of your oven," said Davy Kirkpatrick, a WISE science team member at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, Calif. "With the discovery of Y dwarfs, we've moved out of the kitchen and into the cooler parts of the house."
Kirkpatrick is lead author of a paper appearing in the Astrophysical Journal Supplement Series, describing the 100 confirmed brown dwarfs. Michael Cushing, a WISE team member at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., is lead author of a paper describing the Y dwarfs in the Astrophysical Journal.
The Y dwarfs are in our sun's neighborhood, from approximately nine to 40 light-years away. The Y dwarf approximately nine light-years away, WISE 1541-2250, may become the seventh closest star system, bumping Ross 154 back to eighth. By comparison, the star closest to our solar system, Proxima Centauri, is about four light-years away.
This artist's conception illustrates what brown dwarfs of different types might look like to a hypothetical interstellar traveler who has flown a spaceship to each one. Image credit: NASA / JPL-Caltech.
"Finding brown dwarfs near our sun is like discovering there's a hidden house on your block that you didn't know about," Cushing said. "It's thrilling to me to know we've got neighbors out there yet to be discovered. With WISE, we may even find a brown dwarf closer to us than our closest known star."
Once the WISE team identified brown dwarf candidates, they turned to NASA's Spitzer Space Telescope to narrow their list. To definitively confirm them, the WISE team used some of the most powerful telescopes on Earth to split apart the objects' light and look for telltale molecular signatures of water, methane and possibly ammonia. For the very coldest of the new Y dwarfs, the team used NASA's Hubble Space Telescope. The Y dwarfs were identified based on a change in these spectral features compared to other brown dwarfs, indicating they have a lower atmospheric temperature.
JPL manages WISE for NASA's Science Mission Directorate. The principal investigator is Edward Wright at UCLA. The WISE satellite was decommissioned in 2011 after completing its sky survey observations. The mission was selected under NASA's Explorers Program managed by the Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah, and the spacecraft by Ball Aerospace and Technologies Corp., in Boulder, Colo. Science operations and data processing are at the Infrared Processing and Analysis Center at the California Institute of Technology. For more information about WISE, visit: http://www.nasa.gov/wise and http://wise.astro.ucla.edu
Images (mentioned) Text, Credit: NASA / JPL / Whitney Clavin / Trent J. Perrotto.
Publié par Orbiter.ch à 16:53
lundi 22 août 2011
ESA - BepiColombo Mission patch.
22 August 2011
ESA is recreating the intense sunlight and sustained heat encountered around Mercury, the innermost planet of the Solar System, inside the largest vacuum chamber in Europe.
Mercury Planetary Orbiter
The Netherlands-based test campaign is evaluating ESA’s Mercury Planetary Orbiter (MPO), part of the multi-spacecraft BepiColombo mission to Mercury.
A highly accurate, full-scale engineering model of the final MPO arrived at ESA’s ESTEC Test Centre in Noordwijk from Thales Alenia Space Italy in Turin on 29 July. It has since been placed inside the Large Space Simulator, the largest vacuum chamber in Europe, which is big enough to house an up-ended double-decker bus, and can maintain space-quality vacuum for weeks on end.
The LSS has been specially upgraded to mimic the tenfold increase in solar illumination experienced at Mercury’s distance from the Sun. Its 19 IMAX-projector-class light bulbs are unaltered, but the 121 hexagonal mirrors that reflect their simulated sunlight into the vacuum chamber now provide a much tighter focus for increased intensity.
Large Space Simulator
These illumination levels are so intense that clever engineering was needed to maintain the chamber temperature within safe limits: an extra thermal shroud installed along the simulator walls has increased the flow of liquid nitrogen by more than sixfold, averaging 5000 litres of the –196ºC liquid every hour of each two-week test.
To withstand such extreme conditions, the MPO itself is shrouded in high-temperature blankets and special coatings to help keep it cool, while its interior is fitted with a maze of heat pipes. These pipes work like a closed-loop version of human sweat glands to transport excess heat from MPO’s sunward-side to a radiator facing the other way.
This 2 m x 3.6 m radiator is itself protected by a unique set of coated louvres that prevent the radiator ‘seeing’ the hot planet below it while still permitting its heat to escape to deep space.
The BepiColombo testing began last year with test versions of Japan’s Mercury Magnetosphere Orbiter – which will orbit further away than the MPO and so faces lower levels of heat radiated from Mercury’s surface – plus the ESA-built sunshield that will keep it shaded during its journey to Mercury.
This year, as well as testing the MPO replica, the project will go on to test the Mercury Composite Spacecraft, which is the combination of both orbiters plus sunshield and transfer module that will taxi them across interplanetary space using solar electric propulsion.
BepiColombo’s launch is planned for 2014, arriving in Mercury orbit in 2020. To get more details of current test activities, visit the related links:
BepiColombo in a nutshell: http://www.esa.int/esaSC/SEMLN5T1VED_index_0.html
BepiColombo test diary: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=49053
ESA’s Mercury mapper feels the heat: http://www.esa.int/SPECIALS/Space_Engineering/SEMNBC6SXIG_0.html
How ESTEC turned up temperature for Mercury testing: http://www.esa.int/SPECIALS/Space_Engineering/SEMCL2BE8JG_0.html
Hot stuff: making BepiColombo: http://www.esa.int/SPECIALS/Space_Engineering/SEMZEUISDNG_0.html
Images, Text, Credits: ESA / Remy van Haarlem / Jan van Casteren / Animation by AOES Medialab.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 07:47
In accordance with the schedule of preparation of the launch vehicle (LV), "Soyuz-U" with a cargo ship (SCC) of "Progress M-12M" on the SC in 9 hours 30 minutes Moscow time launch joint calculations began work on the plan the first launch day. Launch vehicle (ILV) is set to start the device, it summed up the farm service.
Soyuz-U with a cargo ship (SCC) of "Progress M-12M" erection on the launch-pad
Running GTK "Progress M-12M" is scheduled for August 24 at 17 hours 00 minutes 11 seconds Moscow time. Cargo ship will deliver the International Space Station in 2670 kg of cargo: scientific equipment, fuel to maintain orbit station, food, water and air for astronauts expendable equipment.
Soyuz-U with a cargo ship (SCC) of "Progress M-12M"
Docking STC "Progress M-12M" to the ISS is scheduled for August 26 at 18 hours 38 minutes.
Text, Credit: Press Service of the Russian Federal Space Agency (Roscosmos PAO) / Photos: Space Center "South" / Translation: Orbiter.ch.
Publié par Orbiter.ch à 05:35
dimanche 21 août 2011
NASA - Mars Exploration Rover "Opportunity" (MER-B) patch.
August 21, 2011
NASA's Mars Exploration Rover Opportunity has captured new images of intriguing Martian terrain from a small crater near the rim of the large Endeavour crater. The rover arrived at the 13-mile-diameter (21-kilometer-diameter) Endeavour on Aug. 9, after a journey of almost three years.
Opportunity is now examining the ejected material from the small crater, named "Odyssey." The rover is approaching a large block of ejecta for investigation with tools on the rover's robotic arm.
Image above: NASA's Mars Exploration Rover Opportunity looked across a small crater on the rim of a much larger crater to capture this raw image from its panoramic camera. Image credit: NASA / JPL-Caltech / Cornell / ASU.
Opportunity and Spirit completed their three-month prime missions on Mars in April 2004. Both rovers continued for years of bonus, extended missions. Both have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life. Spirit ended communications in March 2010.
NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for the NASA Science Mission Directorate, Washington. More information about the rovers is online at: http://www.nasa.gov/rovers or http://marsrovers.jpl.nasa.gov
› Full image and caption: http://www.nasa.gov/mission_pages/mer/multimedia/gallery/pia14532.html
› 'Tisdale 2' Rock: http://www.nasa.gov/mission_pages/mer/multimedia/gallery/pia14535.html
› Soil on Endeavour rim: http://www.nasa.gov/mission_pages/mer/multimedia/gallery/pia14533.html
› View across Endeavour: http://www.nasa.gov/mission_pages/mer/multimedia/gallery/pia14534.html
Image (mentioned), Text, Credit: NASA / JPL / Guy Webster.
Publié par Orbiter.ch à 05:38
August 21, 2011
It's difficult to believe that an airplane flying in the tropics in the summer could have an engine fill up with ice, freeze, and shut down. But the phenomenon, known as engine core ice accretion, has happened more than 150 times since 1988 — frequently enough to attract the attention of NASA aviation safety experts, who are preparing a flight campaign in northern Australia to learn more about this occasional hazard and what can be done to prevent it.
"It's not happening in one particular type of engine and it's not happening on one particular type of airframe," said Tom Ratvasky, an icing flight research engineer at NASA's Glenn Research Center in Cleveland. "The problem can be found on aircraft as big as large commercial airliners, all the way down to business-sized jet aircraft." And it has happened at altitudes up to 41,000 feet.
No accident has been attributed to the phenomenon in the 23 years since it was identified, but there have been some harrowing moments in the air. In most of the known cases, pilots have managed to restore engine power and reach their destinations without further problems. According to the Federal Aviation Administration, there have been two forced landings. For example, in 2005, both engines of a Beechcraft business jet failed at 38,000 feet above Jacksonville, Fla. The pilot glided the aircraft to an airport, dodging thunderstorms and ominous clouds on the way down. Engine core ice accretion was to blame.
Little is understood about ice crystal properties at high altitude and how ice accumulates inside engines. The engines may be toasty warm inside at such heights, but the air outside is frosty cold. The prevailing theory holds the trouble occurs around tropical storms in which strong convection currents move moist air from low altitudes to high altitudes where the local temperatures are very cold, creating high concentrations of ice crystals. But the properties of the ice crystals, such as their size and how many of them are in a given volume of air, are a mystery — one that an international research team led by NASA aims to solve.
This graphic explains what researchers believe might happen to cause engine icing. Credit: NASA / Maria Werries.
The FAA has proposed new certification standards for engines that will be operated in atmospheric conditions that generate ice crystals. The rules will take effect next year, just as the NASA team heads to Darwin, Australia, aboard an aircraft specially equipped with instruments to study cloud physics during the Southern Hemisphere summer. Analyses of the Darwin flight tests and additional tests in ground-based facilities in the United States and Canada will provide the FAA the means for ensuring compliance with the new standards.
"We need to understand what that environment is out there and, even though it may be a rare case, be able to fly through those icing conditions unscathed. Or if we can find ways of detecting this condition and keep aircraft out of it, that's something we're interested in doing," Ratvasky said.
Researchers explain the phenomenon this way: Small ice crystals found in storm clouds get sucked into the core of an aircraft engine, where the pressure is high and the temperature is warm. Some of the ice melts and covers the warm engine parts with a thin film of water that traps additional ice crystals. The super-cooled water chills the engine components enough that ice can accumulate on them. If the built-up ice breaks away in chunks it can damage compressor blades, reduce the power level, or snuff out the engine altogether.
For the flight research, NASA is outfitting a Gulfstream 2 business jet with more than 20 meteorological sensors that will be used to probe cloud properties, such as water content and the size and concentration of ice particles, which can lead to engine and air data sensor failures that threaten aviation safety. The data gathered will aid scientists' understanding of cloud growth processes, help them create reliable detection methods and realistic ground-based simulations, and provide a foundation for possible new aircraft design and certification standards. FAA can use what the team learns over the course of its research project to verify the range of atmospheric conditions addressed in the new standards.
This Gulfstream 2 business jet is being outfitted over the next few months with special sensors to probe cloud properties during the High Ice Water Content experiments. Image credit: NASA.
The flight campaign has three primary goals:
- Characterize the range of environmental conditions in which internal engine icing can take place, with an emphasis on how much water or ice is present in a given volume of air.
- Determine how to identify geographic regions where such weather threatens and ways to detect the conditions in real time in order to develop guidance that pilots can use to avoid the hazard.
- Collect enough data to enable researchers to simulate the weather conditions for aircraft engine tests in ground facilities such as Glenn’s Propulsion Systems Laboratory.
“Our plan is to study the weather patterns that lead to these conditions, not to test a particular engine configuration. We do not plan to intentionally cause our engines to have an icing event,” Ratvasky said.
The Propulsion Systems Laboratory recently underwent upgrades to equip it for ground-based simulations of high-altitude icing conditions. Work to transform the Gulfstream 2 into a working airborne science laboratory is under way at a NASA contractor site, Flight Test Associates in Mojave, Calif., and will be completed early in 2012. Engineers will mount six instruments on each wing and additional instruments on the fuselage to measure cloud particle size and shape and water content, whether the particles are liquid or crystal, and the speed of the updraft as cloud particles form.
The research team – with representatives from FAA, The Boeing Company, the U.S. National Center for Atmospheric Research, Environment Canada, the National Research Council of Canada, Transport Canada, Airbus and the Australian Bureau of Meteorology – will conduct trial runs during the monsoon season in February and March 2012, develop findings and address lessons learned, and then return in January through March 2013 for the primary flight campaign.
The team chose Darwin for several reasons: its ground-based weather observing systems are the best in the tropics, there will be plenty of storms to sample, there is plenty of data from previous atmospheric characterization efforts with which to compare, and the Southeast Asia region has seen a large number of engine power-loss events.
Images (mentioned), Text, Credit: NASA Aeronautics Research Mission Directorate / Jim Banke.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 05:28