PLANCK & HERSCHEL TELESCOPES
Planck Reveals Complexity
of Star Formation
DR EMILY BALDWIN
ASTRONOMY NOW
Posted: 2010 April 27
New images from ESA's Planck Space Observatory reveal the complex driving forces behind star formation,
giving astronomers new insight into the processes that sculpt the dust and gas of our Galaxy.
An active star-formation region in the Orion Nebula, showing also the Horsehead Nebula and Barnard's Loop. This image covers a region of 13x13 degrees.
It is a three-colour combination constructed from three of Planck's nine frequency channels: 30, 353 and 857 GHz. Image: ESA/LFI & HFI Consortia.
The Planck observatory was launched nearly a year ago and with its microwave vision it can penetrate through the shrouds of dust that optical telescopes are blinded by to reveal intricate glowing structures of star-forming gas and dust.
One of Planck's latest study regions is the well-known Orion Nebula, standing out in the first image (above) as the glowing bright spot at the lower centre. The glowing red region above and to the right of that is the Horsehead Nebula, and the giant red arc is known as Barnard’s Loop, a suspected blast wave from a star that expired inside the region around two million years ago but has left its mark as a 300 light-year diameter bubble rippling through the stellar neighbourhood. The second image (below) details the Perseus region, a slightly calmer region of star-formation, compared with Orion.
A low activity, star-formation region in the constellation Perseus, as seen with Planck. This image covers a region of 30x30 degrees.
It is a three-colour combination constructed from three of Planck's nine frequency channels: 30, 353 and 857 GHz. Image: ESA/LFI & HFI Consortia.
Both images reveal three physical processes taking place in the dust and gas of the interstellar medium, covering the frequency range of the space telescope. At lowest frequencies emission caused by high-speed electrons interacting with the Galaxy’s magnetic fields is captured, along with an additional diffuse component that comes from spinning dust particles emitting at these frequencies. At intermediate wavelengths of a few millimetres, the emission is from gas heated by newly formed hot stars.
At higher frequencies Planck can pick out the heat emitted by the cold cores of dust clouds, which cocoon the seeds of future stars. Once born, the newborn stars sweep away the surrounding material. This balancing act of cloud collapse and dispersion acts to regulate the number of stars born in our Galaxy, and thanks to Planck's frequency range this process will be explored with greater clarity than ever, because, for the first time, data will be provided on several major emission mechanisms in one go.
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Jets Carve Out Big Hole
05.11.10
The dark hole seen in the green cloud at the top of this image was likely carved out by multiple jets and blasts of radiation. The hole was originally thought to be a really dark cloud, but this new infrared picture from the Herschel Space Observatory and the National Optical Astronomy Observatory on Kitt Peak near Tucson, reveals that the dark spot is actually a gap in a "nest" of gas and dust containing fledgling stars. Herschel's infrared eyes are designed to see into clouds, so the fact that it saw a dark patch of space told astronomers that they were indeed looking at a hole.
The glowing, green cloud around the hole is called NGC 1999. It contains a fairly bright star, called V38O Ori, which is heating up the dust and creating the bright greenish glow. V380 Ori is a triple star system - one of these three stars appears to have launched a jet that helped clear the hole, as well as other jets and stellar radiation.
The red, filamentary glow extending through the middle of the image is a cloud of cold, dense gas and dust -- the raw material from which new stars are forming. Three new, embryonic stars can bee seen as the triangle of orangish, yellow-white spots. Bipolar jets are visible streaming out of one of these stars in blue. The dark region below and to the right of the top orange-white star of the triangle is thought to be another hole carved by jets from the star. This possible hole is not yet lit up by a star, as is the case with the hole seen above it.
Shorter-wavelength infrared light captured by the "NEWFIRM" camera at the National Optical Astronomy Observatory is colored blue, while longer-wavelength infrared light seen by the photodetector array camera and spectrometer instrument on Herschel is green and red.
Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes and with important participation by NASA. NASA's Herschel Project Office is based at NASA's Jet Propulsion Laboratory. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the United States astronomical community. Caltech manages JPL for NASA.
More information is online at http://www.herschel.caltech.edu, http://www.nasa.gov/herschel and http://www.esa.int/SPECIALS/Herschel/index.html
Image credit: ESA/NASA/JPL-Caltech/Univ. of Toledo
May 10, 2010
The Herschel Space Observatory has made an unexpected discovery: a gaping hole in the clouds surrounding a batch of young stars. The hole has provided astronomers with a surprising glimpse into the end of the star-forming process.
Stars are born hidden in dense clouds of dust and gas, which can now be studied in remarkable detail with Herschel, a European Space Agency mission with important NASA participation. Although jets and winds of gas have been seen streaming from young stars in the past, it has always been a mystery exactly how a star uses the jets to blow away its surroundings and emerge from its birth cloud. For the first time, Herschel may be seeing an unexpected step in this process.
A cloud of bright reflective gas known to astronomers as NGC 1999 sits next to a black patch of sky. For most of the 20th century, such black patches were known to be dense clouds of dust and gas that block light from passing through.
When Herschel looked in its direction to study nearby young stars, astronomers were surprised to see the cloud continued to look black, which shouldn't have been the case. Herschel's infrared eyes are designed to see into such clouds. Either the cloud was immensely dense or something was wrong.
Investigating further using ground-based telescopes, astronomers found the same story no matter how they looked: this patch looks black not because it is a dense pocket of gas but because it is truly empty. Something has blown a hole right through the cloud.
"No one has ever seen a hole like this," says Tom Megeath of the University of Toledo, Ohio, the principal investigator of the research. "It's as surprising as knowing you have worms tunneling under your lawn, but finding one morning that they have created a huge, yawning pit."
The astronomers think that the hole must have been opened when the narrow jets of gas from some of the young stars in the region punctured the sheet of dust and gas that forms NGC 1999. The powerful radiation from a nearby adolescent star may also have helped to clear the hole. Whatever the precise chain of events, it could be an important glimpse into the way newborn stars rip apart their birth clouds.
Other members of the research team include Thomas Stanke of the European Southern Observatory, Germany; Amy Stutz of the Max-Planck Institute for Astronomy, Germany, and the Steward Observatory, Tucson; John Tobin of the University of Michigan, Ann Arbor; Lori Allen of the National Optical Astronomy Observatory, Tucson; Ali Babar of the NASA Herschel Science Center at the California Institute of Technology, Pasadena; and Will Fischer and Erin Kryukova, University of Toledo, Ohio.
Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes and with important participation by NASA. NASA's Herschel Project Office is based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the United States astronomical community. Caltech manages JPL for NASA.
More information is online at http://www.herschel.caltech.edu , http://www.nasa.gov/herschel and http://www.esa.int/SPECIALS/Herschel/index.html .
Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov
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From UniverseToday.com
May 7th, 2010
Written by Nancy Atkinson
The galactic bubble RCW 120. Image credit: ESA/PACS/SPIRE/HOBYS Consortia
Just days before the first anniversary of the Herschel space observatory's launch, the first full science results – along with some very pretty images – were released at a symposium in the Netherlands. "Herschel is a new eye on a part of the cosmos that has been dark and buried for a long time," said the mission's NASA project scientist, Paul Goldsmith at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
Above, Herschel's observation of the star-forming cloud RCW 120 has revealed not only the huge blue bubble of gas, but also the small white spot is what some astronomers have called an "impossible" star.
It already contains eight to 10 times the mass of the sun and is still surrounded by an additional 2,000 solar masses of gas and dust from which it can feed further.
"This star can only grow bigger," says Annie Zavagno, Laboratoire d'Astrophysique de Marseille in France. Massive stars are rare and short-lived. To catch one during formation presents a golden opportunity to solve a long-standing paradox in astronomy. "According to our current understanding, you should not be able to form stars larger than eight solar masses," says Zavagno.
A region the the galactic center in the Eagle constellation. Credits: ESA/Hi-GAL Consortium
This image is taken looking towards a region of the Galaxy in the Eagle constellation, closer to the Galactic center than our Sun. Here, we see the outstanding end-products of the stellar assembly line. At the center and the left of the image, the two massive star-forming regions G29.9 and W43 are clearly visible. These mini-starbursts are forming, as we speak, hundreds and hundreds of stars of all sizes: from those similar to our Sun, to monsters several tens of times heavier than our Sun.
These newborn large stars are catastrophically disrupting their original gas embryos by kicking away their surroundings and excavating giant cavities in the Galaxy. This is clearly visible in the 'fluffy chimney' below W43.
Click the images for larger versions.
See this VIDEO at the ESA website
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NEWS by Kelly Beatty
Planck Sees "First Light"
Have you ever spent hours assembling some complicated gizmo and then anxiously hoped it would work when you turned it on for the first time? Boy, I sure have.
So imagine what must have been going through the minds of the European Space Agency's scientists and engineers a few weeks ago (prior to 2009 Sept 22) as they recorded the first swaths of sky with their shiny new Planck spacecraft.
A 10°-wide swatch of sky from Planck's first-light survey reveals minute temperature fluctuations, differences of only millionths of a degree, in the Cosmic Microwave Background.
ESA / LFI & HFI Consortia
Launched on May 14th (together with an infrared observatory called Herschel), Planck is designed to map feeble microwave emissions over the entire sky. This Cosmic Microwave Background, or CMB, is the relic radiation from the Big Bang — think of it as the afterglow of a dying campfire — and its subtle details can teach us much about how the universe began.
Planck is now situated about 930,000 miles (1½ million km) from Earth, opposite the Sun, at a gravitational balance point known as L2. From there it will scan the entire sky at multiple wavelengths for at least the next 15 months.
This isn't the first spacecraft to map the CMB — the Soviet Union's Prognoz 9 spacecraft took measurements in 1983, and NASA followed with two hugely successful missions: the Cosmic Background Explorer and the still-kicking Wilkinson Microwave Anisotropy Probe, which established our current "era of precision cosmology."
Planck will scan the entire sky to build the most accurate map ever of the Cosmic Microwave Background (CMB), the relic radiation from the Big Bang. Planck will take about 6 months to complete a full scan of the sky, charting two maps during its 15 month-lifetime.
ESA / C. Carreau
Planck will extend this work. To record the minuscule temperature variations present in the CMB, the spacecraft's must be cryogenically cooled to near absolute zero (-460°F or -273°C). The resulting maps should reveal details down to 10 arcminutes (one-third the full Moon's diameter), and the wide frequency coverage will allow astronomers to disentangle foreground radiation from galactic and extragalactic sources from the primordial background signal.
So far, everything is working well. The Planck team has just released the spacecraft's first swaths of survey data, representing two weeks of data collected last month at nine different frequencies. Now Planck is pressing ahead to finish its first all-sky map in about six months. ESA has a nice video that explains how this mapping is done, and you can learn more about the successful first-light observations here.
Posted by Kelly Beatty, September 22, 2009
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August 14th, 2009
From SPACEWEATHER.COM Written by Nancy Atkinson
Artists concept of the Planck spacecraft. Credit: JPL
As of August 13, 2009, the Planck mission is officially in business. It is now seeing light billions of years old, left over from the Big Bang. From its location in the L2 point (SEE DIAGRAM BELOW THIS ARTICLE), the spacecraft started collecting science data as part of the "First Light Survey" which is intended to check out all the systems. If all goes as planned, these observations will be the first of 15 or more months of data gathered from two full-sky scans.
Researcher Chris North wrote on the Planck website that "the major science results will take quite a while to come out due to the immense amount of computation needed to analyze them, and are expected in around 3 years' time. These results will be a full-sky map of the Cosmic Microwave Background, and more accurate measurements of the parameters which have governed how our Universe has evolved."
The mission, which is led by the European Space Agency with important participation from NASA, will help answer the most fundamental of questions: How did space itself pop into existence and expand to become the universe we live in today? The answer is hidden in ancient light, called the cosmic microwave background (CMB), which has traveled more than 13 billion years to reach us. Planck will measure tiny variations in this light with the best precision to date.
After the 15 month prime mission, Planck will continue to scan the sky until its coolant runs out.
For more on Planck, check out these websites:
Cardiff University's Planck website
Filed under: Missions
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More Thoughts (and now math!) On What Came Before the Big Bang
THE PLANCK SPACECRAFT FROM WIKIPEDIA
Planck is a space observatory designed to observe the anisotropies of the cosmic microwave background (CMB) over the entire sky, using high sensitivity and angular resolution. Planck was built in the Cannes Mandelieu Space Center by Thales Alenia Space and created as the third Medium-Sized Mission (M3) of the European Space Agency's Horizon 2000 Scientific Programme. The project—initially called COBRAS/SAMBA after its approval—is named in honour of the German scientist Max Planck (1858–1947), who won the Nobel Prize for Physics in 1918.
The mission will complement and improve upon observations made by the NASA Wilkinson Microwave Anisotropy Probe, which has measured the anisotropies at larger angular scales and lower sensitivity than Planck. Planck will provide a major source of information relevant to several cosmological and astrophysical issues, such as testing theories of the early universe and the origin of cosmic structure.
Objectives
The mission has a wide variety of scientific aims, including:[1]
High resolution detections of both the total intensity and polarization of the primordial CMB anisotropies
Creation of a catalogue of galaxy clusters through the Sunyaev-Zel'dovich effect
Observations of the gravitational lensing of the CMB, as well as the integrated Sachs–Wolfe effect
Observations of bright extragalactic radio (active galactic nuclei) and infrared (dusty galaxy) sources
Observations of the Milky Way, including the local interstellar medium, distributed synchrotron emission and measurements of the galactic magnetic field.
Studies of the local Solar System, including planets, asteroids, comets and the zodiacal light.
Planck represents an advance over WMAP in several respects.
It has higher resolution, allowing it to probe the power spectrum of the CMB to much smaller scales (x3).
It has higher sensitivity (x10).
It observes in nine passbands rather than five with the goal of improving the astrophysical foreground models.
It is expected that most Planck measurements will be limited by how well foregrounds can be subtracted, rather than by the detector performance or length of the mission. This is particularly important for the polarization measurements. The dominant foreground depends on frequency, but examples include synchrotron radiation from the Milky Way at low frequencies, and dust at high frequencies.
Instruments
The spacecraft carries two instruments; the Low Frequency Instrument (LFI) and the High Frequency Instrument (HFI).[1] Both instruments can detect both the total intensity and polarization of photons, and together cover a frequency range of 30 to 857 GHz. The cosmic microwave background spectrum peaks at a frequency of 160.2 GHz
Low Frequency Instrument
The LFI has three frequency bands, covering the range of 30–70 GHz. The detectors use High Electron Mobility Transistors.[1]
High Frequency Instrument
The HFI has six frequency bands, between 100 and 857 GHz. They use bolometers to detect photons. The four lower frequency bands have sensitivity to linear polarization; the two higher bands do not.[1]
NASA
NASA played a role in the development of the mission and will contribute to the analysis of science data. Its Jet Propulsion Laboratory built components of the science instruments, including bolometers for the high-frequency instrument, a 20 Kelvin cryocooler for both the low- and high-frequency instruments, and amplifier technology for the low-frequency instrument.[2]
Service Module – a common development for Herschel and Planck
A common service module (SVM) was designed and built by Thales Alenia Space in its Turin plant, for the Herschel and Planck missions combined into one single program[1] .
Structurally the Herschel and Planck SVM's are very similar. Both SVM's are of octagonal shape and for both, each panel is dedicated to accommodate a designated set of warm units, while taking into account the dissipation requirements of the different warm units, of the instruments as well as the spacecraft.
Furthermore, on both spacecraft a common design for the avionics, the attitude control and measurement system (ACMS) and the command and data management system (CDMS), and power subsystem and the tracking, telemetry and command subsystem (TT&C) has been achieved.
All spacecraft units on the SVM are redundant.
Power Subsystem
On each spacecraft, the power subsystem consists of the solar array, employing triple-junction solar cells, a battery and the power control unit (PCU). It is designed to interface with the 30 sections of each solar array, provide a regulated 28 V bus, distribute this power via protected outputs and to handle the battery charging and discharging.
For Planck, the circular solar array is fixed on the bottom part of the satellite, facing always the sun, as the satellite is spinning around its vertical axis.
Attitude and Orbit Control
This function is performed by the attitude control computer (ACC) which is the platform for the ACMS. It is designed to fulfil the pointing and slewing requirements of the Herschel and Planck payload.
The Planck satellite is spun at one revolution per minute, the absolute pointing error needs to be less than 37 arc min. For Planck being a survey platform, there is also a requirement to be met on pointing reproducibility error to be less than 2.5 arc min over 20 days.
The main sensor of the line of sight in both spacecraft is the star tracker.
Launch and orbit
The satellite was successfully launched, along with the Herschel Space Observatory, at 13:12:02 on 14 May 2009 aboard an Ariane 5 ECA heavy launch vehicle. The launch placed the craft into a very elliptical orbit (perigee: 270 km, apogee: more than 1,120,000 km), bringing it near the L2 Lagrangian point of the Earth-Sun system, 1.5 million kilometers from the Earth.
The maneuver to inject Planck into its final orbit around L2 was successfully completed on July 3, 2009, when it entered a Lissajous orbit of 400,000 km radius around the L2 Lagrangian point.[3] The temperature of the High Frequency Instrument reached just a tenth of a degree above absolute zero (0.1 K) on July 3, 2009, placing both the Low Frequency and High Frequency Instruments within their cryogenic operational parameters, making Planck fully operational.[4]
Results
A part of the Herschel Planck team, from left to right : Jean-Jacques Juillet, Head of scientific programmes Thales Alenia Space ; Marc Sauvage, CEA, responsible Herschel PACS Experience ; François Bouchet, IAP, responsible Planck exploitation ; Jean-Michel Reix, Head of Herschel & Planck Programmes, Thales Alenia Space, for the presentations of the first results of Herschel & Planck missions, Cannes, October 2009
On September 2009, ESA announced the preliminary results from the Planck First Light Survey (performed to demonstrate the stability of the instruments and the ability to calibrate them over long periods). This results indicate that the data quality is excellent. [5]
The final results (with all processed data) are expected to be delivered to the worldwide community towards the end of 2012.
See also
References
^ a b c d e Planck Science Team (2005) (.PDF). Planck: The Scientific Programme (Blue Book). ESA-SCI (2005)-1. Version 2. European Space Agency. http://www.rssd.esa.int/SA/PLANCK/docs/Bluebook-ESA-SCI%282005%291_V2.pdf. Retrieved 2009-03-06.
^ "Planck: Exploring the Birth of Our Universe". NASA.gov. http://www.nasa.gov/mission_pages/planck/overview.html. Retrieved September 26, 2009.
^ "Esa, latest news". European Space Agency. http://www.rssd.esa.int/index.php?project=PLANCK&page=dev_news.
^ "Planck instruments reach their coldest temperature". European Space Agency. http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=45133.
^ "Planck first light yields promising results". European Space Agency. http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=45543.
Dambeck, Thorsten (May 2009). "Planck Readies to Dissect the Big Bang". Sky and Telescope: pp. 24-28.
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THE ASTRONOMY PICTURE OF THE DAY FOR 2009 OCTOBER 16
Herschel Views the Milky Way
Credit: ESA, SPIRE & PACS Consortia
Explanation: With a 3.5 meter diameter mirror, larger than the 2.4 m Hubble Space Telescope, Herschel is ESA's new infrared observatory.
The space-based telescope is named for German-born British astronomer Frederick William Herschel who discovered infrared light over
200 years ago. In initial tests, Herschel's cameras have combined to deliver this spectacular view along the plane of the Milky Way in the
constellation of the Southern Cross. Spanning some 2 degrees the premier, false-color, far-infrared view captures our galaxy's cold
dust clouds in extreme detail, showing a remarkable, connected maze of filaments and star-forming regions. These and planned future
Herschel observations are intended to unravel mysteries of star formation by surveying broad areas of the galactic plane.
Big Pix from Herschel
Europe's new Herschel Space Observatory is all checked out and in excellent working order, as the European Space Agency demonstrated this morning with its release of a gorgeous nebula picture (Enlarged Above).
In this far-infrared mosaic image from Herschel, we see right through cold, dense molecular clouds near the plane of the Milky Way in the constellation Crux, the Southern Cross. The frame is nearly 2° tall. Emission at 70 microns is shown here as blue, 160 microns as green, and 250, 350, and 500 microns are combined as red. Click for full-size views and more information.
ESA and the SPIRE & PACS consortia
With an aperture of 3.5 meters, Herschel is the largest space telescope yet flown (Hubble is 2.4 meters). Perhaps more importantly, Herschel works in the far-infrared part of the spectrum: a poorly explored realm between the familiar, shorter-wavelength "warm infrared" and the millimeter-wave and microwave radio bands. Its cameras can work at six far-infrared and submillimeter colors, with wavelengths around 70, 110, 160, 250, 350, and 500 microns. Such wavelengths are the ones most strongly emitted by objects that are extremely cold — not far above absolute zero.
What we see in the picture here (a mosaic of many small frames) is mostly very cold interstellar dust. It's not reflecting starlight but glowing with the characteristic, very weak thermal emission for such temperatures. Blue and green here represent two of Herschel's shorter wavelengths, highlighting less-cold dust. Red indicates longer wavelengths and colder material. Notice the bright points of star formation happening inside a few of the densest, coldest filaments, almost like pearls on a string.
This is just a taste. In the coming months and years there'll be lots more.
Posted by Alan MacRobert of Sky and Telescope Magazine, October 2, 2009
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December 16th, 2009
From UNIVERSETODAY.COM
Written by Nancy Atkinson
Herschel looks deep inside the heart of a dark cloud located 1000 light years away in the constellation Aquila, the Eagle.
Credit: ESA and the SPIRE and PACS consortia
The science teams from the Herchel telescope are meeting this week to discuss their first results from the intial months of observations by
the newest infrared space telescope, which was launched in May. While details of the scientific findings won't be released until Friday after
everyone at the meetings has had a chance to share their results, ESA released a few stunning new pictures to give everyone a sample of
what is to come. In addition to the images shown here, hints of other upcoming images include the most distant known quasar, a
dwarf planet, and water sublimating from a comet's surface. Some of the images have been described as among the most important images
obtained from space for decades.
Above, Herschel peered deep inside an unseen stellar nursery in located 1000 light years away in the constellation Aquila, the Eagle,
revealing a surprising amounts of activity. Some 700 newly-forming stars are estimated to be crowded into filaments of dust stretching
through the image. The image is the first new release of ‘OSHI’, ESA’s Online Showcase of Herschel Images.
Herschel's look at the Southern Cross. Credits: ESA and the PACS consortium
Another images release of the Southern Cross shows that even the darkest patches of sky can shine brightly to Herschel. Usually, this
starregion looks like a bland cloud of dust, but Herschel shows it to be a place of intense formation with filaments and condensations of dust
cocooning newly forming stars. The dust forms into clumps along magnetic lines – like pearls on a necklace. Each clump is a very early
star – at its embryonic stage.
The third image is of the spiral galaxy M51, also known as the Whirlpool Galaxy, showing off its spectacular infrared colors. Two huge waves
of star formation encircle its central nucleus, making beautiful spiral arms. Each one shines brightly with its dust being warmed by the
Herschel's Whirlpool Galaxy. Credit: ESA and PACS team
Source: OSHI
Filed under: Missions
Tags: Herschel Telescope, Infrared Astronomy
Related stories on Universe Today
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HERSCHEL
Exploring the formation of galaxies and stars
Découvrir la formation des galaxies et des étoiles
T : : Days
Hours
Minutes
Seconds
(AS OF 2009 DEC 19 AT 3:30 AM EST Elapsed time since launch on 2009 May 14 at 13:12 (UTC).
Click on http://herschel.esac.esa.int/ for an updated clock
Welcome to the Herschel Astronomers' website provided by the Herschel Science Centre (HSC) primarily for the scientific community. For additional ESA and external Herschel related websites see link buttons above and "Useful links".
Herschel was launched on 2009 May14! It is the fourth `cornerstone' mission in the ESA science programme. With a 3.5 meter Cassegrain telescope it became the largest space telescope ever launched. It will perform photometry and spectroscopy in approximately the 55-672 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
Herschel is designed to observe the `cool universe'; it has the potential of elucidating structure formation in the universe, resolving the far infrared cosmic background, revealing cosmologically evolving AGN/starburst symbiosis and galaxy evolution at the epochs when most stars in the universe were formed, unveiling the physics and chemistry of the interstellar medium and its molecular clouds, the wombs of the stars, and unravelling the mechanisms governing the formation of and evolution of stars and their planetary systems, including our own solar system putting it into context. In short, Herschel will open a new window to study how the universe has evolved to become the universe we see today, and how our star the sun, our planet the earth, and we ourselves fit in. For abstracts of accepted Herschel observing programmes see "Key Programmes".
Herschel will be operated as an observatory facility. Commencing about six months after launch it will offer three years of routine science observations. It will be available for the worldwide scientific community, with roughly two thirds of the observing time being `open time', which will be allocated through a standard competitive proposal procedure.
Recent and Future Milestones include:
Herschel views the sky! As part of the commissioning activities Herschel has viewed the sky with spectacular results! See the 'sneak preview', 'first light' and 'first SPIRE/PACS parallel mode' webreleases. Always check the progress on Latest News and the HSC Operations (B)Log.
Herschel cryocover opened on 14 June 2009! The Herschel cryostat lid (the cryocover) was commanded open on 14 June 2009, precisely one month after the launch. Follow the progress on "Latest News" and the "HSC Operations (B)Log".
Herschel was launched on 2009 May 14! The Herschel launch campaign was brought to an end by a flawless launch into the sky above Kourou. The Ariane 5 ECA launcher disappeared from sight after just a couple of minutes, and Herschel was later released into its desired transfer trajectory 26 minutes after liftoff. Follow the progress on "Latest News" and the "HSC Operations (B)Log".
Two Herschel 'hands-on' DP workshops have been conducted by the Herschel Science Centre with partners in ESAC on 24-27 March 2009; see "Latest News".
The Key Programme (KP) time allocation process has been completed for both guaranteed time (GT) and open time (OT) observations. In addition to the 21 KP GT programmes by coincidence also precisely 21 KP OT programmes have been awarded observing time. The contents of these programmes are described under "Key Programmes".
Last updated: Friday, 02-Oct-2009 09:37:21 CEST
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Late News from the European Space Agency (ESA)
3 July: in the early hours of 3 July, the cold end of the dilution cooler crossed the magical line of 0.1 K !! From now on, both Planck instruments are observing the sky. This is a very big milestone for Planck... Hurrah ! Roughly at the same time, the manoeuver to inject Planck into its final orbit around L2 (See Diagram Below) was successfully completed. The Planck payload is now fully operational and coming very close to start routine observing of the sky.
The diagram above shows the five Lagrangian points in a two-body system with one body far more massive than the other (e.g. the Sun and the Earth). In such a system, L3–L5 will appear to share the secondary's orbit, although in fact they are situated slightly outside it. L1 is about 930,000 miles from the earth (bluedot) towards the sun and L2 is the same distance from the earth, but away from the sun.
30 June: In the past week, the LFI has begun to tune its amplifiers. Stable temperature plateaus were provided by judicious use of coolers and heat switches, in an intricate collaborative scheme between LFI and HFI. the 4K cooler stroke and 0.1 K cooler flow rate were set to full amplitude on 27 June and the cooling of the lowest temperature stages accelerated dramatically. On 29 June, the cold end of the 4K cooler achieved 4 K. One day later, the 0.1 K stage had crossed the 10 K line. The lowest temperatures are coming closer !
15 June: the sorption cooler has achieved its nominal temperature. . The temperatures on the sorption cooler side of the interface is ~17.5 K. The third V-groove is at about 45 K. Record temperatures !
14 June: the LFI front-ends have been turned on and are behaving nominally, producing science data. This was the last major payload element remaining to be turned on. Planck is now fully alive !
11 June: the first excitement related to the payload: yesterday evening the sorption cooler unexpectedly turned itself off. The anomaly was quickly traced to a safety threshold which had been incorrectly set. It was updated and sorption cooler restarted within a few hours. The cool-down profile was hardly affected.
9 June 2009: the big manoeuver has been completed: ~155 m/s were expended over ~46 hrs. A very slight overperformance will be compensated with a touch-up manoeuver on 17 June. In the meantime, the payload is cooling down as planned: the Sorption Cooler cold-end is following very closely the cool-down profile which was achieved during ground testing (at CSL), and the HFI focal plane is also cooling down as predicted. It is expected now to achieve 20 K at the sorption cooler cold-end sometime during the weekend.
4 June 2009: both the sorption cooler and the LFI have been switched on, are healthy and doing what they are expected to do. Big smiles on everybody's faces ! Tomorrow: execution of the big manoeuver will start and will last around one day.
3 June 2009: the (LFI) focal plane has been cooling down a little slower than expected, it should reach 100 K early on 4 June. For this reason the sorption cooler switch-on has been delayed until 4 June. In the meantime, the sorption cooler electronics has been activated and works nominally.
2 June 2009: the satellite spent a quiet weekend "parked" and waiting for the anticontamination process to end. On 1 June the anticontamination heaters were switched off and the payload has started to cool again. The sorption cooler will be turned on tomorrow (3 June).
27 May 2008: we are two weeks on the way to L2 ! The diagram below shows the current trajectory of Planck to L2. Each tick mark corresponds to two weeks (we are at the first tickmark). The next orbital transfer manoeuver is planned to start on 5 June.
[Note: The coordinate system is an osculating, co-rotating Earth/MoonBarycentre -Sun system: X axis along the Sun - Earth/MoonBarycentre direction; Z axis along the angular momentum vector of the Earth/MoonBarycentre movementaround the Sun; Y axis completes the right hand system. The origin of the system is the Earth/Moon barycentre, thus, you find the Sun in -x direction. The figure is by R. Cramm from ESOC.]
27 May 2008: The checkout of the on-board computer has been completed. Also the Service Module's power management system, thermal control system have been tested and are nominal. The telemetry and telecommand subsystem have been characterised and behave well. Further tests of the attitude control system are ongoing. The next big milestone will be the interruption of the anti-contamination heating, to take place on 1 June, to be followed on 3 June by the switch-on of the sorption cooler.
21 May 2009: As planned, the focal plane and reflector temperatures have been stabilised at 170 K to prevent contamination from outgassing. The 3rd V-groove is already at around 60 K and dropping. The cooldown rates are close to what is expected. The first days of commissioning have focussed on testing the attitude control system. Both large and small slews have been executed. The thruster behavior is better than expected and will ease operations later on. Despite rumours, the star trackers are working fine so far. The Fiber-Optic Gyro has been turned on and data acquired.
18 May 2009: the Launch and Early Orbit Phase has successfully concluded with all planned activities successfully carried out (including activation of dilution cooler valves, 4K cooler, etc). All systems are working well. The HFI has been turned on and the noise levels are as expected at this stage. The payload temperatures are now dropping passively as predicted and will be stabilised when it reaches 170 K. The commissioning activities have begun and will continue for approximately 6 weeks.
Planck was successfully launched on 2009 May 14 into its planned trajectory towards L2.
Pictures and videos of the launch can be obtained from Sci-Tech Planck pages, under News and Announcements, and in the main ESA/Planck pages.
THE EUROPEAN SPACE AGENCY (ESA) HAS LAUNCHED TWO GREAT NEW OBSERVATORIES -
1)THE PLANCK OBSERVATORY TO MAP THE COSMIC MICROWAVE BACKGROUND RADIATION IN GREATER DETAIL THEN ITS PREDECESSORS - COBE AND WMAP
2)THE HERSCHEL OBSERVATORY WHICH WILL STUDY THE UNIVERSE WITH UNPRECEDENTED ACCURACY IN THE INFRARED PART OF THE SPECTRUM WITH A 3.5 METER MIRROR UNTIL THE JAMES WEBB SPACE TELESCOPE WITH A 6.5 METER MIRROR IS LAUNCHED IN ABOUT 4 OR 5 YEARS.
LAUNCH OCCURRED: 9:12:02 AM EDT ON 2009 MAY 14 from Europe’s Spaceport in Kourou, French Guiana
DIAGRAM ABOVE SHOWS THE 5 LIBRATION (BALANCE)
OR LAGRANGIAN POINTS WHERE THE GRAVITY OF THE
SUN AND EARTH -1 MILLION MILES AWAY- ARE EQUAL.
LITTLE FUEL IS NEEDED TO ORBIT THESE POINTS. L1 AND L2
ARE THE POINTS CHOSEN DUE TO THE PROXIMITY TO EARTH.
SOHO IS AT L1 SINCE IT STUDIES THE SUN AND
WMAP WHICH NEEDS DARK SKIES IS LOCATED AT L2.
7 seconds after ignition of the main stage cryogenic engine, two solid-propellant boosters are ignited, and we have liftoff. The launch begins with a 6 second vertical climb. The onboard computers optimize the motion of the rocket in real time, in order to minimize fuel consumption. The main stage engine takes the launcher into an intermediate orbit before the end stage takes the payload into the final orbit. You can clearly see the change between the two stages on the velocity and acceleration graphs at about 9 minutes.
The main stage of the launcher will apparently fall back, just off the coast of Africa in the Atlantic Ocean. The launcher will remain at an altitude of about 852 kilometers travelling at about 10,000 meters/second! The fairing protecting the Herschel, Planck spacecraft is jettisoned shortly after the boosters.
By the end of the process, Herschel and Planck will be on their way to a placed called ‘L2′ (SEE DIAGRAMS ABOVE and BELOW), a point in space where objects sit ‘behind’ the Earth with respect to the Sun (see diagram below). L2 is a good spot for space-based observatories because they are effectively ‘towed’ around in orbit with the Earth but remain roughly stationary with respect to it.
An object at L2 will maintain the same orientation with respect to the Sun and Earth. At L2, the Earth constantly shields objects from the Sun - ideal for highly heat- or light-sensitive equipment. Herschel and Planck will not be alone at L2. The Wilkinson Microwave Anisotropy Probe (WMAP) is already there and the Gaia mission and James Webb Space Telescope will also be placed at L2.
The Herschel space telescope has two main objectives: observation of the “cold” Universe, in particular the formation of stars and galaxies; and studying the chemical composition of celestial bodies and the molecular chemistry of the Universe. Herschel’s mirror, at 3.5 meters in diameter, will be the largest ever deployed in space. It will wiegh over 3,400 kg at launch. For more info visit the ESA Herschel page.
Planck is designed to analyze the remnants of the radiation that filled the Universe immediately after the Big Bang, which we observe today as the cosmic microwave background. Planck will provide vital information concerning the creation of the Universe and the origins of the cosmic structure. It will weigh 1,920 kg at launch. For more info visit the ESA Planck page.
__________________________________
May 14th, 2009
Written by Nancy Atkinson
Ariane V launch. Credit: Arianespace tv
The Herschel and Planck spacecraft successfully launched together Thursday,May 14 from Europe’s Spaceport in Kourou, French Guiana. The Ariane V rocket performed flawlessly, with the rocket’s trajectory matching exactly the predicted flight path. The two spacecraft separated individually and in different directions from the launch vehicle, about four minutes apart, after spinning to orient themselves correctly for their high elliptical orbits. Just 40 minutes after lift-off, Herschel and Planck sent their first radio signals to Earth, confirming that they both are operating in good shape. In a few months, they will arrive at the L-2 (Lagrange) point in space, 1.5 million kilometers (930,000 miles) from Earth, beyond the Moon’s orbit. By early next year (2010), they’ll begin operations to open new windows on the Universe. Herschel will be studying star formation while Planck will be looking back at the Big Bang.
Herschel will be looking at specific points in space while Planck will look at the whole sky.
Herschel in 3-D. Credit: Nathanial Burton-Bradford.
This 3-D image of Herschel was created by Nathanial Burton-Bradford. Check out other images at his Flickr page.
Named after the 18th century astronomer who discovered infrared light, the Herschel spacecraft is 7 meters in length and 4 meters wide. The telescope mirror is 3.5 meters wide, 4 times bigger than previous space telescope, and will collect long-wavelength radiation from some of the coldest and most distant objects in the Universe. The mirror is also a technological wonder: it uses 12 silicon carbide petals fused together into a single piece. Herschel will be the only space observatory to cover a spectral range from the far infrared to sub-millimeter.
To detect cold, dark objects, Herschel has to be even colder. 2,400 liters of liquid helium cools the spacecraft to -273 Celsius. Like a thermal camera can see a person’s body heat, Herschel will look beyond dust and gas to see inside star forming regions, study comets and look into the distant universe where galaxies collide and give birth to stars. Scientists are planning for at least three years of operation from Herschel.
Planck. Credit: ESA
Planck will be sweeping the whole sky continuously to map out a picture of the Universe as it was 13.7 million years ago. The spacecraft is four by four meters, with a 1.5 meter primary mirror that is surrounded with a baffle to limit any stray light from nearby objects, the Sun, Earth and Moon. Planck’s detectors have to be cold as well, and will be chilled to between 273 C to just 1/10th of degree above Absolute Zero.
Routine observations with Planck are expected to last for at least 15 months. The mission could be extended depending on the status of helium 3 isotope that is being used to chill the spacecraft.
Planck will test key questions in cosmology, investigating the cosmic microwave background, to ascertain the primordial constituents of the universe, and look for existence of gravitational waves. Planck will journey back in time, while giving us a better understanding of the future.
Filed under: Missions, Space Flight
Herschel Space Observatory
From Wikipedia, the free encyclopedia
For the Canary Islands ground-based telescope, see William Herschel Telescope.
The Herschel Space Observatory is a space observatory from the European Space Agency (ESA). It was originally proposed in 1982 by a consortium of European scientists. The mission is named after Sir William Herschel, the discoverer of the infrared spectrum and planet Uranus.[1]
Science
Herschel will specialise in collecting light from objects in our Solar System as well as the Milky Way and even extragalactic objects billions of light-years away, such as newborn galaxies, and is charged with four primary areas of investigation:[2]
Galaxy formation in the early universe and the evolution of galaxies;
Star formation and its interaction with the interstellar medium;
Chemical composition of atmospheres and surfaces of Solar System bodies, including planets, comets and moons;
Molecular chemistry across the universe.
Instrumentation
The mission, formerly titled the Far Infrared and Sub-millimetre Telescope (FIRST), involves the first space observatory to cover the full far infrared and submillimetre waveband.[2] At 3.5 meters wide, its telescope incorporates the largest mirror ever deployed in space.[3] The light is focused onto three instruments with detectors kept at temperatures below 2 K (−271 °C). The instruments are cooled with liquid helium, boiling away in a near vacuum at a temperature of approximately 1.4 K (−272 °C). The 2,000-litre supply of helium on board the satellite will limit its operational lifetime, nonetheless it is expected to be operational for at least 3 years.[4]
Herschel carries three detectors:[5]
PACS (Photodetecting Array Camera and Spectrometer)
An imaging camera and low-resolution spectrometer covering wavelengths from 55 to 210 micrometres. The spectrometer has a spectral resolution between R=1000 and R=5000 and is able to detect signals as weak as −63dB. The imaging camera can image simultaneously in two bands (either 60–85/85–130 micrometres and 130–210 micrometres) with a detection limit of a few millijanskys.[6]
SPIRE (Spectral and Photometric Imaging Receiver)
An imaging camera and low-resolution spectrometer covering 194 to 672 micrometre wavelength. The spectrometer has a resolution between R=40 and R=1000 at a wavelength of 250 micrometres and is able to image point sources with brightnesses around 100 millijanskys (mJy) and extended sources with brightnesses of around 500 mJy.[7] The imaging camera has three bands, centered at 250, 350 and 500 micrometres, each with 139, 88 and 43 pixels respectively. It should be able to detect point sources with brightness above 2 mJy and between 4 and 9 mJy for extended sources. A prototype of the SPIRE imaging camera flew on the BLAST high-altitude balloon.
HIFI (Heterodyne Instrument for the Far Infrared)
A heterodyne detector which is able to electronically separate radiation of different wavelengths, giving a spectral resolution as high as R=107.[8] The spectrometer can be operated within two wavelength bands, from 157 to 212 micrometres and from 240 to 625 micrometres.
Service Module – a common development for Herschel and Planck
A common service module (SVM) was designed and built by Thales Alenia Space in its Turin plant, for the Herschel and Planck missions combined into one single program[9].
Structurally the Herschel and Planck SVM's are very similar. Both SVM's are of octagonal shape and for both, each panel is dedicated to accommodate a designated set of warm units, while taking into account the dissipation requirements of the different warm units, of the instruments as well as the spacecraft.
Furthermore, on both spacecraft a common design for the avionics, the attitude control and measurement system (ACMS) and the command and data management system (CDMS), and power subsystem and the tracking, telemetry and command subsystem (TT&C) has been achieved.
All spacecraft units on the SVM are redundant.
Power Subsystem
On each spacecraft, the power subsystem consists of the solar array, employing triple-junction solar cells, a battery and the power control unit (PCU). It is designed to interface with the 30 sections of each solar array, provide a regulated 28 V bus, distribute this power via protected outputs and to handle the battery charging and discharging.
For Herschel, the solar array is fixed on the bottom part of the baffle designed to protect the cryostat from the sun. The three-axis attitude control system maintains this baffle in direction of the sun. The top part of this baffle is covered with Optical solar reflector (OSR) mirrors reflecting 98% of the sun energy, avoiding heating of the cryostat.
Attitude and Orbit Control
This function is performed by the attitude control computer (ACC) which is the platform for the ACMS. It is designed to fulfil the pointing and slewing requirements of the Herschel and Planck payload.
The Herschel satellite is three-axis stabilized, the absolute pointing error needs to be less than 3.7 arc sec.
The main sensor of the line of sight in both spacecraft is the star tracker.
Launch and orbit
The satellite, built in the Cannes Mandelieu Space Center, under Thales Alenia Space Contractorship, was successfully launched from the Guiana Space Centre in French Guiana at 13:12:02 UTC on 14 May 2009, aboard an Ariane 5 rocket, along with the Planck spacecraft.[10][11].
It is now on a very elliptical orbit (perigee: 270.0 km (intended 270.0±4.5), apogee: 1,197,080 km (intended 1,193,622±151,800), inclination 5.99 deg (intended 6.00±0.06)[12]), on its way towards the second Lagrangian point.
On June 14, 2009, ESA successfully sent the command for the cryocover to open which will allow the PACS system to see the sky and transmit images in a few weeks. The lid had to remain closed until the telescope was well into space to prevent contamination. Herschel is reported to have completed 90% of the distance to its orbit 1.5 million km away from Earth.[13][14] Five days later the first set of test photos, depicting M51 Group, was published by ESA.[15]
In July 2009, approximately sixty days after launch, it is expected to enter a Lissajous orbit of 800,000 km average radius around the second Lagrangian point (L2) of the Earth-Sun system, 1.5 million kilometres from the Earth.[1]
See also
References
^ a b "Herschel Factsheet". European Space Agency. 17 April 2009. http://www.esa.int/esaSC/SEMA539YFDD_index_0.html. Retrieved on 2009-05-12.
^ a b "Herschel". European Space Agency Science & Technology. http://sci.esa.int/science-e/www/area/index.cfm?fareaid=16. Retrieved on 2007-09-29.
^ "Herschel Space Observatory". Imperial College. http://astro.imperial.ac.uk/Research/Infrared/Herschel/. Retrieved on 2007-09-29.
^ Jonathan Amos (9 February 2009). "'Silver Sensation' Seeks Cold Cosmos". BBC News. http://news.bbc.co.uk/2/hi/science/nature/7864087.stm. Retrieved on 2009-03-06.
^ "Herschel: Science payload". European Space Agency. 20 November 2008. http://www.esa.int/esaSC/120390_index_0_m.html. Retrieved on 2009-03-07.
^ "PACS – Photodetector Array Camera and Spectrometer". http://herschel.esac.esa.int/Docs/Flyers/PACS_flyer_4July2007.pdf. Retrieved on 2007-09-29.
^ "SPIRE – Spectral and Photometric Imaging Receiver". European Space Agency. http://herschel.esac.esa.int/Docs/Flyers/SPIRE_flyer_4July2007.pdf. Retrieved on 2007-09-29.
^ "HIFI – Heterodyne Instrument for the Far Infrared". European Space Agency. http://herschel.esac.esa.int/Docs/Flyers/HIFI_flyer_4July2007.pdf. Retrieved on 2007-09-29.
^ Planck Science Team (2005) (.PDF). Planck: The Scientific Programme (Blue Book). ESA-SCI (2005)-1. Version 2. European Space Agency. http://www.rssd.esa.int/SA/PLANCK/docs/Bluebook-ESA-SCI%282005%291_V2.pdf. Retrieved on 2009-03-06.
^ Leo Cendrowicz (14 May 2009). "Two Telescopes to Measure the Big Bang". Time. http://www.time.com/time/health/article/0,8599,1898174,00.html. Retrieved on 2009-05-16.
^ (.SWF) Launch of Herschel and Planck satellites. [video]. Arianespace. http://www.videocorner.tv/videocorner2/live_flv/index.php?langue=en. Retrieved on 2009-05-16.
^ Herschel Science Centre Operations (B)Log. European Space Agency. 14 May 2009. Retrieved on 2009-05-18
^ Amos, Jonathan (June 14, 2009). "Herschel telescope 'opens eyes'". BBC News. http://news.bbc.co.uk/2/hi/science/nature/8099105.stm. Retrieved on 2009-06-14.
^ "Cryocover Opens!". WordPress.com.. June 14, 2009. http://herschelmission.wordpress.com/. Retrieved on 2009-06-14.
^ "Herschel's 'sneak preview': a glimpse of things to come". ESA. 2009-06-19. http://herschel.esac.esa.int/SneakPreview.shtml. Retrieved on 2009-06-19.
Further reading
Harwit M. (2004). "The Herschel Mission". Advances in Space Research 34 (3): 568–572. doi:10.1016/j.asr.2003.03.026.
Thorsten Dambeck (May 2009). "One Launch, Two New Explorers: Planck Readies to Dissect the Big Bang". Sky and Telescope: pp. 24–28.
News related to ESA launches Herschel Space Observatory and Planck Satellite at Wikinews
External links
Planck (spacecraft)
From Wikipedia, the free encyclopedia
Planck
General information
European Space Agency with Thales Alenia Space as Prime Contractorship
2009-05-14 13:12:02 UTC = May 14 at
9:12:02 AM EDT
elapsed: 2 months and 6 days
1.5 million km
(L2 Lagrangian point)
350 to 10,000 µm
Instruments
Low Frequency Instrument (LFI)
High Frequency Instrument (HFI)
Website
Planck is a space observatory designed to observe the anisotropies of the Cosmic Microwave Background (CMB) over the entire sky, using high sensitivity and angular resolution. Planck was built in the Cannes Mandelieu Space Center by Thales Alenia Space and created as the third Medium-Sized Mission (M3) of the European Space Agency's Horizon 2000 Scientific Programme. The project—initially called COBRAS/SAMBA after its approval—is named in honour of the German scientist Max Planck (1858–1947), who won the Nobel Prize for Physics in 1918.
The mission will complement and improve upon observations made by the NASA Wilkinson Microwave Anisotropy Probe (WMAP), which has measured the anisotropies at larger angular scales and lower sensitivity than Planck. Planck will provide a major source of information relevant to several cosmological and astrophysical issues, such as testing theories of the early universe and the origin of cosmic structure.
Objectives
The mission has a wide variety of scientific aims, including:[1]
High resolution detections of both the total intensity and polarization of the primordial CMB anisotropies
Creation of a catalogue of galaxy clusters through the Sunyaev-Zel'dovich effect
Observations of the gravitational lensing of the CMB, as well as the integrated Sachs–Wolfe effect
Observations of bright extragalactic radio (active galactic nuclei) and infrared (dusty galaxy) sources
Observations of the Milky Way, including the local interstellar medium, distributed synchrotron emission and measurements of the galactic magnetic field.
Studies of the local Solar System, including planets, asteroids, comets and the zodiacal light.
Planck represents an advance over WMAP in several respects.
It has higher resolution, allowing it to probe the power spectrum of the CMB to much smaller scales (x3).
It has higher sensitivity (x10).
It observes in nine passbands rather than five with the goal of improving the astrophysical foreground models.
It is expected that most Planck measurements will be limited by how well foregrounds can be subtracted, rather than by the detector performance or length of the mission. This is particularly important for the polarization measurements. The dominant foreground depends on frequency, but examples include synchrotron radiation from the Milky Way at low frequencies, and dust at high frequencies.
Instruments
The spacecraft carries two instruments; the Low Frequency Instrument (LFI) and the High Frequency Instrument (HFI).[1] Both instruments can detect both the total intensity and polarization of photons, and together cover a frequency range of 30 to 857 GHz. The cosmic microwave background spectrum peaks at a frequency of 160.2 GHz
Low Frequency Instrument
The LFI has three frequency bands, covering the range of 30–70 GHz. The detectors use High Electron Mobility Transistors.[1]
High Frequency Instrument
The HFI has six frequency bands, between 100 and 857 GHz. They use bolometers to detect photons. The four lower frequency bands have sensitivity to linear polarization; the two higher bands do not.[1]
Service Module – a common development for Herschel and Planck
A common service module (SVM) was designed and built by Thales Alenia Space in its Turin plant, for the Herschel and Planck missions combined into one single program[1] .
Structurally the Herschel and Planck SVM's are very similar. Both SVM's are of octagonal shape and for both, each panel is dedicated to accommodate a designated set of warm units, while taking into account the dissipation requirements of the different warm units, of the instruments as well as the spacecraft.
Furthermore, on both spacecraft a common design for the avionics, the attitude control and measurement system (ACMS) and the command and data management system (CDMS), and power subsystem and the tracking, telemetry and command subsystem (TT&C) has been achieved.
All spacecraft units on the SVM are redundant.
Power Subsystem
On each spacecraft, the power subsystem consists of the solar array, employing triple-junction solar cells, a battery and the power control unit (PCU). It is designed to interface with the 30 sections of each solar array, provide a regulated 28 V bus, distribute this power via protected outputs and to handle the battery charging and discharging.
For Planck, the circular solar array is fixed on the bottom part of the satellite, facing always the sun, as the satellite is spinning around its vertical axis.
Attitude and Orbit Control
This function is performed by the attitude control computer (ACC) which is the platform for the ACMS. It is designed to fulfil the pointing and slewing requirements of the Herschel and Planck payload.
The Planck satellite is spun at one revolution per minute, the absolute pointing error needs to be less than 37 arc min. For Planck being a survey platform, there is also a requirement to be met on pointing reproducibility error to be less than 2.5 arc min over 20 days.
The main sensor of the line of sight in both spacecraft is the star tracker.
Launch and orbit
The satellite was successfully launched, along with the Herschel Space Observatory, at 13:12:02 on 14 May 2009 aboard an Ariane 5 ECA heavy launch vehicle. The launch placed the craft into a very elliptical orbit (perigee: 270 km, apogee: more than 1,120,000 km), bringing it near the L2 Lagrangian point of the Earth-Sun system, 1.5 million kilometers from the Earth.
The maneuver to inject Planck into its final orbit around L2 was successfully completed on July 3, 2009, when it entered a Lissajous orbit of 400,000 km radius around the L2 Lagrangian point.[2] The temperature of the High Frequency Instrument reached just a tenth of a degree above absolute zero (0.1 K) on July 3, 2009, placing both the Low Frequency and High Frequency Instruments within their cryogenic operational parameters, making Planck fully operational.[3]
See also
[ References
^ a b c d e Planck Science Team (2005) (.PDF). Planck: The Scientific Programme (Blue Book). ESA-SCI (2005)-1. Version 2. European Space Agency. http://www.rssd.esa.int/SA/PLANCK/docs/Bluebook-ESA-SCI%282005%291_V2.pdf. Retrieved on 2009-03-06.
^ "Esa, latest news". European Space Agency. http://www.rssd.esa.int/index.php?project=PLANCK&page=dev_news.
^ "Planck instruments reach their coldest temperature". European Space Agency. http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=45133.
Further reading
Thorsten Dambeck in Sky and Telescope, Planck Readies to Dissect the Big Bang, May 2009, pp. 24–28