WISE mission

[Waspie_Dwarf]

NASA Says: 'Build It and Infrared Surprises Will Come'

Engineers are rolling up their sleeves in preparation for building a telescope that will find the nearest star-like objects and the brightest galaxies. NASA has approved the start of construction on a new mission called the Wide-field Infrared Survey Explorer, which will scan the entire sky in infrared light.

"There's a whole infrared sky out there full of surprises," said Dr. Edward Wright, principal investigator for the mission at the University of California, Los Angeles. "By surveying the entire sky, we are bound to find new and unexpected objects."

Image above: Artist's concept of Wide-field

Infrared Survey Explorer.

Image credit: NASA/JPL

+ Full image and caption

+ Browse version of image

An estimated $300-million mission, the Wide-field Infrared Survey Explorer, or "Wise," has been in the planning stages for the past eight years. It is scheduled to launch into an Earth orbit in late 2009. It will spend seven months collecting data.

Such extensive sky coverage means the mission will find and catalogue all sorts of celestial eccentrics. These may include brown dwarfs, or failed stars, that are closer to Earth than Proxima Centauri, the nearest star other than our sun. Brown dwarfs are balls of gas that begin life like stars but lack the mass to ignite their internal fires and light up like normal stars. They do, however, produce warm infrared glows that Wise will be able to see.

"Brown dwarfs are lurking all around us," said Dr. Peter Eisenhardt, project scientist for the mission at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We believe there are more brown dwarfs than stars in the nearby universe, but we haven't found many of them because they are too faint in visible light."

Wright, Eisenhardt and other scientists recently identified brown dwarfs using NASA's infrared Spitzer Space Telescope. Wise will vastly expand the search, uncovering those brown dwarfs closest to Earth that might make ideal targets for future planet-hunting missions. Recent Spitzer findings support the notion that planets might orbit brown dwarfs.

Wise might also find the most luminous galaxies in the universe, some so far away that their light has taken 11.5 billion years to reach Earth. Galaxies in the distant, or early, universe were much brighter than our own Milky Way galaxy, but dust thought to exist in these objects blocks much of their ultraviolet and visible light. These dusty coats light up at infrared wavelengths; however, the galaxies are few and far between, so they can be difficult to find. Wise will comb the whole sky in search of them.

"It's hard to find the most energetic galaxies if you don't know where to look," said Eisenhardt. "We're going to look everywhere."

The spacecraft's detectors will be approximately 500 times more sensitive than those of a previous infrared survey mission, called the Infrared Astronomical Satellite, a joint European-NASA venture that operated in 1983.

JPL manages the Wide-field Infrared Survey Explorer mission for NASA's Science Mission Directorate and Explorer Program. The Explorer Program is managed by NASA's Goddard Space Flight Center, Greenbelt, Md. The infrared cryogenic instrument for Wise will be designed and built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft will be built by Ball Aerospace and Technologies Corporation in Boulder, Colo. Mission operations will be conducted at JPL, and images will be processed and distributed at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. The Center for Science Education at the University of California, Berkeley, Space Sciences Laboratory, will manage the Wise education program. JPL is a division of the California Institute of Technology in Pasadena.

For more information on NASA's Wise mission, visit http://wise.ssl.berkeley.edu/. For more information on NASA and agency programs, visit http://www.nasa.gov/home.

Media contact: Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

2006-130

Source: NASA/JPL - News

Edited December 11, 2009 by Waspie_Dwarf
fixed broken links

[RollingThunder06]

With it in operation for only seven months I hope it can record fast and give us a lot of information.

[Waspie_Dwarf]

WISE

Wide-field Infrared Survey Explorer

Mission Overview

Artist's concept of the Wide-field Infrared

Survey Explorer.

Image credit: NASA/JPL-Caltech

› Full image

The Wide-field Infrared Survey Explorer, or WISE, will scan the entire sky in infrared light, picking up the glow of hundreds of millions of objects and producing millions of images. The mission will uncover objects never seen before, including the coolest stars, the universe's most luminous galaxies and some of the darkest near-Earth asteroids and comets. Its vast catalogs will help answer fundamental questions about the origins of planets, stars and galaxies, and provide a feast of data for astronomers to munch on for decades to come.

Thanks to next-generation technology, WISE's sensitivity is hundreds of times greater than its predecessor, the Infrared Astronomical Satellite, which operated in 1983.

WISE will join two other infrared missions in space -- NASA's Spitzer Space Telescope and the Herschel Space Observatory, a European Space Agency mission with important NASA participation. WISE is different from these missions in that it will survey the entire sky. It is designed to cast a wide net to catch all sorts of unseen cosmic treasures, including rare oddities.

The closest of WISE's finds will be near-Earth objects, both asteroids and comets, with orbits that come close to crossing Earth's path. The mission is expected to find hundreds of these bodies, and hundreds of thousands of additional asteroids in our solar system's main asteroid belt. By measuring the objects' infrared light, astronomers will get the first good estimate of the size distribution of the asteroid population. This information will tell us approximately how often Earth can expect an encounter with a potentially hazardous asteroid. WISE data will also reveal new information about the composition of near-Earth objects and asteroids -- are they fluffy like snow or hard like rocks, or both?

The next closest targets for WISE are dim stars called brown dwarfs. These Jupiter-like balls of gas form like stars but fail to gather up enough mass to ignite like stars. The objects are cool and faint, and nearly impossible to see in visible light. WISE should uncover about 1,000 in total, and will double or triple the number of star-like objects known within 25 light-years of Earth. What's more, if a brown dwarf is lurking closer to us than the closest known star, Proxima Centauri, WISE will find it and the little orb will become famous for being the "closest known star."

The most distant objects that will stand out like ripe cherries in WISE's view are tremendously energetic galaxies. Called ultraluminous infrared galaxies, or ULIRGs, these objects shine with the light of up to a trillion suns. They crowd the distant universe, but appear virtually absent in visible-light surveys. WISE should find millions of ultra-luminous infrared galaxies, and the most luminous of these could be the most luminous galaxy in the universe.

Other nuggets to come out of the WISE survey will be newborn stars; disks of planetary debris around young stars; a detailed look at the structure of our Milky Way galaxy; clusters of galaxies in the far universe and more. The most interesting finds will lay the groundwork for follow-up studies with other missions, such as NASA's Spitzer Space Telescope, the Herschel Space Observatory, NASA's Hubble Space Telescope, NASA's upcoming SOFIA airborne telescope and NASA's upcoming James Webb Space Telescope. Powerful ground-based telescopes will also follow up on WISE discoveries.

As with past all-sky surveys, surprises are sure to come. For example, one of the most surprising finds to come out of the Infrared Astronomical Satellite mission was the discovery of excess infrared light around familiar stars like Vega and Fomalhaut. Astronomers soon determined that the excess light comes from pulverized rock in disks of planetary debris. The findings implied that rocky planets like Earth could be common. Today hundreds of astronomers study these debris disks, and Hubble recently captured an actual photograph of a planet orbiting Fomalhaut within its disk.

WISE will orbit Earth at an altitude of 525 kilometers (326 miles), circling Earth via the poles about 15 times a day. A scan mirror within the WISE instrument will stabilize the line of sight so that snapshots can be taken every 11 seconds over the entire sky. Each position on the sky will be imaged a minimum of eight times, and some areas near the poles will be imaged more than 1,000 times.

The mission's sensitive infrared telescope and detectors are kept chilled inside a Thermos-like tank of solid hydrogen, called a cryostat. This prevents WISE from picking up the heat, or infrared, signature of its own instrument. The solid hydrogen, called a cryogen, is expected to last about 10 months and will keep the WISE telescope a chilly 17 degrees Kelvin (minus 429 degrees Fahrenheit).

After a one-month checkout period, the infrared surveyor will spend six months mapping the whole sky. It will then begin a second scan to uncover even more objects and to look for any changes in the sky that might have occurred since the first survey. This second partial sky survey will end about three months later when the spacecraft's frozen-hydrogen cryogen runs out. Data from the mission will be released to the astronomical community in two stages: a preliminary release will take place six months after the end of the survey, or about 16 months after launch, and a final release is scheduled for 17 months after the end of the survey, or about 27 months after launch.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The mission's principal investigator, Edward L. (Ned) Wright, is at UCLA. The mission was competitively selected in 2002 under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp, Boulder, Colo. Science operations and data processing will take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

The mission's education and public outreach office is based at the University of California, Berkeley.

Source: NASA - WISE - Mission Overview

[Waspie_Dwarf]

NASA's WISE Mission Arrives at Launch Site

08.17.09

WISE arrives at Vandenberg Air Force Base.

Credit: NASA

› Larger image

PASADENA, Calif. -- NASA's Wide-field Infrared Survey Explorer, or WISE, has arrived at its last stop on Earth -- Vandenberg Air Force Base, Calif.

WISE is scheduled to blast into space in December, aboard a United Launch Alliance Delta II rocket from NASA's Space Launch Complex 2. Orbiting around Earth, it will scan the entire sky at infrared wavelengths, unveiling hundreds of thousands of asteroids, and hundreds of millions of stars and galaxies.

The spacecraft arrived at Vandenberg along the central California coast today, after a winding journey via truck from Ball Aerospace & Technologies Corporation in Boulder, Colo. Ball built the mission's spacecraft; its telescope and science instrument were built by Space Dynamics Laboratory in Logan, Utah.

"WISE has arrived and is almost ready to go," said William Irace, the mission's project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "After we check the spacecraft out and fill the telescope cooling tanks with solid hydrogen, we'll mate it to the rocket and launch."

WISE is an infrared space telescope like two currently orbiting missions, NASA's Spitzer Space Telescope and the Herschel Space Observatory, a European Space Agency mission with important NASA participation. But, unlike these missions, WISE will survey the entire sky. It is designed to cast a wide net to catch all sorts of unseen cosmic treasures. Millions of images from the survey will serve as rough maps for other observatories, such as Spitzer and NASA's upcoming James Webb Space Telescope, guiding them to intriguing targets.

"WISE will survey the cosmic landscape in the infrared so that future telescopes can home in on the most interesting 'properties,'" said Edward Wright, the principal investigator for the mission at UCLA.

The infrared surveyor will pick up the heat from a cornucopia of objects, both near and far. It will find hundreds of thousands of new asteroids in our main asteroid belt, and hundreds of near-Earth objects, which are comets and asteroids with orbits that pass relatively close to Earth. The mission will uncover the coldest stars, called brown dwarfs, perhaps even one closer to us than our closest known neighbor, Proxima Centauri, which is 4 light-years away. More distant finds will include nurseries of stars, swirling planet-building disks and the universe's most luminous galaxies billions of light-years away.

The data will help answer fundamental questions about how solar systems and galaxies form, and will provide the astronomical community with mountains of data to mine.

"WISE will create a legacy that endures for decades," said Peter Eisenhardt, the mission's project scientist at JPL. "Today, we still refer to the catalogue of our predecessor, the Infrared Astronomical Satellite, which operated in 1983."

The Infrared Astronomical Satellite was a joint infrared survey mission between NASA, the United Kingdom and the Netherlands. WISE's survey, thanks to next-generation technology, will be hundreds of times more sensitive.

The mission will scan the sky from a sun-synchronous orbit, 500 kilometers (about 311 miles) above Earth. After a one-month checkout period, it will map the whole sky over a period of six months. Onboard frozen hydrogen, which will cool the infrared detectors, is expected to last several months longer, allowing WISE to map much of the sky a second time and see what has changed.

JPL manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate. The mission's principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing will take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

NASA’s Launch Services Program at the Kennedy Space Center in Florida is responsible for government oversight of the Delta II and launch countdown management.

More information is online at http://wise.astro.ucla.edu.

Media contact: Whitney Clavin/JPL

818-354-4673

Source: NASA - Universe - Features

[Waspie_Dwarf]

In Search of Dark Asteroids (and Other Sneaky Things)

09.15.2009

Ninjas knew how to be stealthy: Be dark. Emit very little light. Move in the shadows between bright places.

In modern warfare, though, ninjas would be sitting ducks. Their black clothes may be hard to see at night with the naked eye, but their warm bodies would be clearly visible to a soldier wearing infrared goggles.

To hunt for the "ninjas" of the cosmos — dim objects that lurk in the vast dark spaces between planets and stars — scientists are building by far the most sensitive set of wide-angle infrared goggles ever, a space telescope called the Widefield Infrared Survey Explorer (WISE).

Above: An artist's concept of the Widefield

Infrared Survey Explorer (WISE). [more]

WISE will scan the entire sky at infrared wavelengths, creating the most comprehensive catalog yet of dark and dim objects in the cosmos: vast dust clouds, brown dwarf stars, asteroids — even large, nearby asteroids that might pose a threat to Earth.

Surveys of nearby asteroids based on visible-light telescopes could be skewed toward asteroids with more-reflective surfaces. "If there's a significant population of asteroids nearby that are very dark, they will have been missed by these previous surveys," says Edward Wright, principal investigator for WISE and a physicist at the University of California in Los Angeles.

The full-sky infrared map produced by WISE will reveal even these darker asteroids, mapping the locations and sizes of roughly 200,000 asteroids and giving scientists a clearer idea of how many large and potentially dangerous asteroids are nearby. WISE will also help answer questions about the formation of stars and the evolution and structure of galaxies, including our own Milky Way.

And the discoveries won't likely stop there.

"When you look at the sky with new sensitivity and a new wavelength band, like WISE is going to do, you're going to find new things that you didn't know were out there," Wright says.

Stars emit visible light in part because they're so hot. But cooler objects like asteroids emit light too, just at longer, infrared wavelengths that are invisible to the unaided eye. In fact, any object warmer than absolute zero will emit at least some infrared light.

Unfortunately, this fact makes building an infrared telescope rather difficult. Without a coolant, the telescope itself would glow in infrared light just like all other warm objects do. It would be like building a normal, visible-light telescope out of Times Square billboard lights: The telescope would be blinded by its own glow.

To solve this problem, WISE will cool its components to about 15°C above absolute zero (or -258°C) using a block of solid hydrogen. Mission scientists chose solid hydrogen over liquid helium, which is often used in research for cooling materials to near absolute zero, because a smaller volume of solid hydrogen can do the job. "The cooling power is much higher for hydrogen than for helium," Wright explains. When launching a telescope into space, being smaller and lighter saves money.

Above: The WISE 2-stage solid hydrogen dewar

resembles R2D2 from Star Wars. [more]

Previous space telescopes such as the Infrared Astronomical Satellite (IRAS) have mapped the sky at infrared wavelengths before, but WISE will be hundreds of times more sensitive. While other missions could only see diffuse sources of infrared light such as large dust clouds, WISE will be able to see asteroids and other point sources.

After it launches into orbit as early as this December, WISE will spend 6 months mapping the sky, during which it will download its data to ground stations 4 times each day. Analyzing that data should give scientists some new insights into the cosmos.

For example, one theory posits that most of the stars in the Universe were formed in the press of colliding galaxies. When galaxies collide, interstellar clouds of gas and dust smash together, compressing the clouds and starting a self-perpetuating cycle of gravitational collapse. The result is a flurry of starbirth. Newborn stars are usually concealed by the dusty clouds they are born in. Ordinary light cannot escape, but infrared light can.

Above: Colliding spiral galaxies NGC 2207 and IC 2163.

Image credit: Hubble Space Telescope. [more]

WISE will be able to detect infrared emissions from the most active star-forming regions. This will help scientists know how rapidly stars are formed during galactic collisions, which could indicate how many of the universe's stars were formed this way.

WISE will also target dim "failed stars" called brown dwarfs that outnumber ordinary stars by a wide margin. Mapping brown dwarfs in the Milky Way may reveal much about the structure and evolution of our own galaxy.

And this could be just the beginning of the discoveries scientists make once WISE puts the spotlight on stealthy denizens of the dark.

Author: Patrick Barry | Editor: Dr. Tony Phillips | Credit: Science@NASA

---

more information

WISE mission fact sheet (pdf)

WISE Home Page

Source: Science@NASA

[Waspie_Dwarf]

WISE Mission Assembled and Preparing for Launch

06.10.09

WISE Project Scientist Peter Eisenhardt

stands next to the fully assembled WISE

satellite at Ball Aerospace & Technologie

Corp., in Boulder, Colorado.

Image credit: NASA/JPL-Caltech/Ball

Full-resolution JPEG (3.5MB)

PASADENA, Calif. -- NASA's Wide-field Infrared Survey Explorer, or WISE, has been assembled and is undergoing final preparations for a planned Nov. 1 launch from Vandenberg Air Force Base, Calif.

The mission will survey the entire sky at infrared wavelengths, creating a cosmic clearinghouse of hundreds of millions of objects -- everything from the most luminous galaxies, to the nearest stars, to dark and potentially hazardous asteroids. The survey will be the most detailed to date in infrared light, with a sensitivity hundreds of times better than that of its predecessor, the Infrared Astronomical Satellite.

"Most of the sky has never been imaged at these infrared wavelengths with this kind of sensitivity," said Edward Wright, the mission's principal investigator at UCLA. "We are sure to find many surprises."

On May 17, the mission's science instrument was delivered to Ball Aerospace & Technologies Corp. in Boulder, Colo., where it was attached to the spacecraft, built by Ball. The assembled unit was then blasted by sound to simulate the effects of launch. Tests for electronic "noise" in the detectors will be performed next.

The science instrument is a 40-centimeter (16-inch) telescope with four infrared cameras. A cryostat, or cooler, uses frozen hydrogen to chill the sensitive megapixel infrared detectors down to seven Kelvin (minus 447 degrees Fahrenheit). The instrument was built by Space Dynamics Laboratory in Logan, Utah.

Among expected finds from WISE are hundreds of thousands of asteroids in our solar system's asteroid belt, and hundreds of additional asteroids that come near Earth. Many asteroids have gone undetected because they don't reflect much visible light, but their heat makes them glow in infrared light that WISE can see. By cataloguing the objects, the mission will provide better estimates of their sizes, a critical step for assessing the risk associated with those that might impact Earth.

"We know that asteroids occasionally hit Earth, and we'd like to have a better idea of how many there are and their sizes," said Amy Mainzer of NASA's Jet Propulsion Laboratory, Pasadena, Calif., the mission's deputy project scientist. "Whether they are dark or shiny, they all emit infrared light. They can't hide from WISE."

The mission is also expected to find the coldest stars -- dim orbs called brown dwarfs that are too small to have ignited like our sun. Brown dwarfs are littered throughout our galaxy, but because they are so cool, they are often too faint to see in visible light. The infrared detectors on WISE will pick up the glow of roughly 1,000 brown dwarfs in our galaxy, including those coldest and closest to our solar system. In fact, astronomers say the mission could find a brown dwarf closer to us than the nearest known star, Proxima Centauri, located approximately 4 light-years away.

"We've been learning that brown dwarfs may have planets, so it's possible we'll find the closest planetary systems," said Peter Eisenhardt, the mission's project scientist at JPL. "We should also find many hundreds of brown dwarfs colder than 480 degrees Celsius (900 degrees Fahrenheit), a group that as of now has only nine known members."

In addition, the survey will reveal the universe's most luminous galaxies seen long ago in the dusty throes of their formation, disks of planet-forming material around stars, and other cosmic goodies. The observations will guide other infrared telescopes to the most interesting objects for follow-up studies. For example, NASA's Spitzer Space Telescope, the Herschel observatory just launched by ESA with significant NASA participation, and NASA's upcoming James Webb Space Telescope will direct their gaze at objects uncovered by WISE.

WISE will lift off from Vandenberg aboard a United Launch Alliance Delta II rocket. It will orbit Earth, mapping the entire sky in six months after a one-month checkout period. Its frozen hydrogen is expected to last several months longer, allowing WISE to map much of the sky a second time and see what has changed.

JPL manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate. The mission's principal investigator, Edward Wright, is at UCLA. The mission was developed under NASA's Explorer Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory and the spacecraft was built by Ball Aerospace & Technologies Corp. Science operations and data processing will take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information is online at http://wise.ssl.berkeley.edu/mission.html.

The Infrared Astronomical Satellite, launched in 1983, was a joint mission between NASA, the United Kingdom and the Netherlands.

Media contact: Whitney Clavin/JPL

818-354-4673

Source: NASA - Missions - WISE - News & Media Resources

Edited December 11, 2009 by Waspie_Dwarf

[Waspie_Dwarf]

WISE Is Chilling Out

11.11.09

A scaffolding structure built around NASA's

Wide-field Infrared Survey Explorer, or WISE,

allows engineers to freeze its hydrogen

coolant. The WISE infrared instrument is

kept extremely cold by a bottle-like tank

filled with frozen hydrogen, called the

cryostat. The cryostat can be seen at the

top of the spacecraft.

Image credit: NASA/JPL-Caltech/

Space Dynamics Lab

› Larger image

Engineers are busy cooling the science instrument on NASA's Wide-field Infrared Survey Explorer, or WISE. The spacecraft is scheduled to blast into space from Vandenberg Air Force Base in California on Dec. 7, 2009. It will map the entire sky in infrared light, uncovering all sorts of hidden treasures -- everything from the coolest stars to dark asteroids and the most luminous galaxies.

To see infrared light from the cosmos, WISE must be chilled to out-of-this-world cold temperatures. This prevents the telescope from picking up its own infrared glow, or heat. A bottle-like chamber, called a cryostat, surrounds and cools the telescope and detectors. The cryostat will be filled with frozen hydrogen, which slowly evaporates away over a period of about 10 months -- enough time for WISE to scan the sky one-and-a-half times.

On Thursday, Oct. 29, engineers began the process of pumping hydrogen gas into the cryostat's two tanks, one after the other. Surrounding pipes filled with liquid helium are used to cool and condense the hydrogen gas to a liquid. Once a tank is filled with liquid hydrogen, the liquid helium flow is turned up. This freezes the hydrogen solid. The engineers control and monitor the process round-the-clock with the help of a scaffolding structure built around WISE.

"We want the hydrogen gas to convert to a liquid before it freezes so that it fills up the tanks from bottom to top, allowing us know where the hydrogen is," said John Elwell, the project manager for the science instrument on WISE. Elwell and his team, from the Space Dynamics Laboratory in Logan, Utah, are responsible for building, testing and cooling the instrument.

Ultimately, the hydrogen will be cooled down to below a mere 7 Kelvin, or minus 266 degrees Celsius (minus 447 degrees Fahrenheit). That's just 7 degrees Celsius above absolute zero -- the coldest temperature theoretically attainable. The coldest of WISE's detectors will operate at below 8 degrees Kelvin (minus 265 degrees Celsius or minus 445 degrees Fahrenheit).

Liquid helium will continue to be piped around the cryostat until 19 hours before launch. At that point, WISE will be perfectly chilled out and ready to see our universe's true infrared colors.

NASA's Jet Propulsion Laboratory manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The mission's principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu.

Source: NASA - Missions - WISE - News & Media Resources

Edited December 11, 2009 by Waspie_Dwarf

[Waspie_Dwarf]

NASA's WISE Gets Ready to Survey the Whole Sky

11.17.09

This artist's conception shows NASA's

Wide-field Infrared Survey Explorer, or

WISE, mapping the whole sky in infrared.

The mission will unveil hundreds of

thousands of asteroids, and hundreds of

millions of stars and galaxies.

Image credit: Ball/NASA/JPL-Caltech

› Full image and caption

› Related images and video

PASADENA, Calif. -- NASA's Wide-field Infrared Survey Explorer, or WISE, is chilled out, sporting a sunshade and getting ready to roll. NASA's newest spacecraft is scheduled to roll to the pad on Friday, Nov. 20, its last stop before launching into space to survey the entire sky in infrared light.

WISE is scheduled to launch no earlier than 6:09 a.m. PST (9:09 a.m. EST) on Dec. 9 from Vandenberg Air Force Base in California. It will circle Earth over the poles, scanning the entire sky one-and-a-half times in nine months. The mission will uncover hidden cosmic objects, including the coolest stars, dark asteroids and the most luminous galaxies.

"The eyes of WISE are a vast improvement over those of past infrared surveys," said Edward "Ned" Wright, the principal investigator for the mission at UCLA. "We will find millions of objects that have never been seen before."

The mission will map the entire sky at four infrared wavelengths with sensitivity hundreds to hundreds of thousands of times greater than its predecessors, cataloging hundreds of millions of objects. The data will serve as navigation charts for other missions, pointing them to the most interesting targets. NASA's Hubble and Spitzer Space Telescopes, the European Space Agency's Herschel Space Observatory, and NASA's upcoming Sofia and James Webb Space Telescope will follow up on WISE finds.

"This is an exciting time for space telescopes," said Jon Morse, NASA's Astrophysics Division director at NASA Headquarters in Washington. "Many of the telescopes will work together, each contributing different pieces to some of the most intriguing puzzles in our universe."

Visible light is just one slice of the universe's electromagnetic rainbow. Infrared light, which humans can't see, has longer wavelengths and is good for seeing objects that are cold, dusty or far away. In our solar system, WISE is expected to find hundreds of thousands of cool asteroids, including hundreds that pass relatively close to Earth's path. WISE's infrared measurements will provide better estimates of asteroid sizes and compositions -- important information for understanding more about potentially hazardous impacts on Earth.

"With infrared, we can find the dark asteroids other surveys have missed and learn about the whole population. Are they mostly big, small, fluffy or hard?" said Peter Eisenhardt, the WISE project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

WISE also will find the coolest of the "failed" stars, or brown dwarfs. Scientists speculate it is possible that a cool star lurks right under our noses, closer to us than our nearest known star, Proxima Centauri, which is four light-years away. If so, WISE will easily pick up its glow. The mission also will spot dusty nests of stars and swirling planet-forming disks, and may find the most luminous galaxy in the universe.

To sense the infrared glow of stars and galaxies, the WISE spacecraft cannot give off any detectable infrared light of its own. This is accomplished by chilling the telescope and detectors to ultra-cold temperatures. The coldest of WISE's detectors will operate at below 8 Kelvin, or minus 445 degrees Fahrenheit.

"WISE is chilled out," said William Irace, the project manager at JPL. "We've finished freezing the hydrogen that fills two tanks surrounding the science instrument. We're ready to explore the universe in infrared."

JPL manages WISE for NASA's Science Mission Directorate in Washington. The mission was competitively 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 was built by Ball Aerospace & Technologies Corp. in Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information about WISE is available online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu.

Source: NASA - Missions - WISE - News & Media Resources

Edited December 11, 2009 by Waspie_Dwarf

[Waspie_Dwarf]

Mapping the Infrared Sky

11.17.09

This artist's conception shows NASA's Wide-field Infrared Survey Explorer, or WISE, mapping the whole sky in infrared. The mission will unveil hundreds of thousands of asteroids, and hundreds of millions of stars and galaxies.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The mission's principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu.

Image credit: Ball/NASA/JPL-Caltech

› Full resolution jpeg (65 Kb)

Source: NASA - Missions - WISE - News & Multimedia

Edited January 2, 2010 by Waspie_Dwarf

[Waspie_Dwarf]

Brown Dwarf Comparison

11.17.09

NASA's Wide-field Infrared Survey Explorer, or WISE, will uncover many "failed" stars, or brown dwarfs, in infrared light. This diagram shows a brown dwarf in relation to Earth, Jupiter, a low-mass star and the sun.

Stars with less mass than the sun are smaller and cooler, and hence much fainter in visible light. Brown dwarfs are the smallest and coolest of stars. They have less than eight percent of the mass of the sun, which is not enough to sustain the fusion reaction that keeps the sun hot. These cool orbs are nearly impossible to see in visible light, but stand out when viewed in infrared. Their diameters are about the same as Jupiter's, but they can have up to 80 times more mass and are thought to have planetary systems of their own.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The mission's principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu.

Image Credit: NASA/JPL-Caltech/UCB

› Full resolution jpeg (75 Kb)

Source: NASA - Missiond - WISE - News & Multimedia

[Waspie_Dwarf]

New Cool Stars

11.17.09

Astronomers think there are roughly as many brown dwarfs as regular stars like our sun, but brown dwarfs are often too cool to find using visible light. These tiny orbs are similar to stars but they are cooler and less massive. They lack the mass to fuse atoms at their cores and shine with starlight. Using infrared light, NASA's Wide-field Infrared Survey Explorer (WISE), will find many dozens of brown dwarfs within 25 light years of the sun.

These two pictures show simulated data before and after the WISE mission (stars are not real). The simulated picture on the left shows known stars (white and yellow) and brown dwarfs (red) in our solar neighborhood. The picture on the right shows additional brown dwarfs WISE is expected to find. One of these newfound brown dwarfs could even be closer to us than our closest known star, Proxima Centauri, which is four light-years away.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The mission's principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu.

Image credit: AMNH/Caltech/UCB

› Full resolution jpeg (92 Kb)

Source: NASA - Missiond - WISE - News & Multimedia

[Waspie_Dwarf]

WISE Spacecraft in Clean Room

11.17.09

The Wide-field Infrared Survey Explorer, or WISE, in the clean room at Ball Aerospace & Technologies Corp., in Boulder, Colo.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The mission's principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu.

Image credit: NASA/JPL-Caltech/Ball

› Full resolution jpeg (137 Kb)

Source: NASA - Missiond - WISE - News & Multimedia

[Waspie_Dwarf]

WISE L-20 News Conference

17 November 2009

NASA's Wide-field Infrared Survey Explorer, or Wise, is chilled out, sporting a sunshade and getting ready to roll. NASA's newest spacecraft is scheduled to roll to the pad on Friday, Nov. 20, its last stop before launching into space to survey the entire sky in infrared light.

Wise is scheduled to launch no earlier than 9:09 a.m. EST on Dec. 9 from Vandenberg Air Force Base in California. It will circle Earth over the poles, scanning the entire sky one-and-a-half times in nine months. The mission will uncover hidden cosmic objects, including the coolest stars, dark asteroids and the most luminous galaxies.

"The eyes of Wise are a vast improvement over those of past infrared surveys," said Edward "Ned" Wright, the principal investigator for the mission at UCLA. "We will find millions of objects that have never been seen before."

The mission will map the entire sky at four infrared wavelengths with sensitivity hundreds to hundreds of thousands of times greater than its predecessors, cataloging hundreds of millions of objects. The data will serve as navigation charts for other missions, pointing them to the most interesting targets. NASA's Hubble and Spitzer Space Telescopes, the European Space Agency's Herschel Space Observatory, and NASA's upcoming Sofia and James Webb Space Telescope will follow up on Wise finds.

Source: NASA Channel - YouTube

[Waspie_Dwarf]

Celestial Treasure Hunt

19 November 2009

NASA scientist Dr. Amy Mainzer describes how the Wide-field Infrared Survey Explorer (WISE) will provide a map to the universe's hidden treasures.

Source: NASA Channel - YouTube

[Waspie_Dwarf]

NASA's WISE Gets Ready to Survey the Whole Sky

11.17.09

NASA's Wide-field Infrared Survey Explorer,

or WISE, is seen here being hoisted to

the top of its United Launch Alliance

Detla II rocket at Vandenberg Air Force

Base, Calif. The spacecraft, which will

scan the whole sky in infrared light, is

scheduled to blast off on Dec. 9, 2009.

Image credit:NASA/JPL-Caltech

› Larger image

NASA's Wide-field Infrared Survey Explorer, or WISE, is now perched atop its rocket at Vandenberg Air Force Base, north of Santa Barbara, Calif. The mission, which will scan the whole sky in infrared light, is scheduled to blast off on Dec. 9. It was hoisted to the top of its United Launch Alliance Delta II rocket on Friday, Nov. 20.

JPL manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The mission's principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information is online http://www.nasa.gov/wise and http://wise.astro.ucla.edu.

Source: NASA - Missions - WISE - News & Media Resources

[Waspie_Dwarf]

WISE Snug in Its Nose Cone

11.30.09

WISE is shown inside one-half of the nose

cone, or fairing, that will protect it during

launch. The spacecraft is clamped to the top

of the rocket above the white conical fitting.

The fairing will split open like a clamshell

about five minutes after launch.

Credit: United Launch Alliance/JPL-Caltech

› Larger image

NASA's Wide-field Infrared Survey Explorer has been wrapped in the outer nose cone, or "fairing," that will protect it during its scheduled Dec. 9 launch from Vandenberg Air Force Base, Calif.

The fairing will split open like a clamshell about five minutes after launch. The spacecraft will circle Earth over the poles, scanning the entire sky one-and-a-half times in nine months. The mission will uncover hidden cosmic objects, including the coolest stars, dark asteroids and the most luminous galaxies.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages WISE for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information is online http://www.nasa.gov/wise and http://wise.astro.ucla.edu.

Source: NASA - Missions - WISE - News & Media Resources

[Waspie_Dwarf]

NASA's WISE Set to Blast Off and Map the Skies

12.09.09

Artist's concept of the Wide-field Infrared

Survey Explorer.

Image credit: NASA/JPL

› Larger image

PASADENA, Calif. -- The countdown clock is ticking, with just days to go before the Wide-field Infrared Survey Explorer, or WISE, rockets into space on a mission to map the entire sky in infrared light.

NASA's newest spacecraft is currently perched atop a United Launch Alliance Delta II rocket at Vandenberg Air Force Base, north of Santa Barbara, Calif. It is scheduled to roar into space at dawn on Dec. 11, at 6:09:33 a.m. PST (9:09:33 a.m. EST), on a short journey to its final Earth-circling orbit 525 kilometers (326 miles) overhead.

After a one-month checkout, the mission will spend the next nine months mapping the cosmos in infrared light. It will cover the whole sky one-and-a-half times, snapping millions of pictures of everything from near-Earth asteroids to faraway galaxies bursting with new stars.

"The last time we mapped the whole sky at these particular infrared wavelengths was 26 years ago," said Edward (Ned) Wright of UCLA, who is the principal investigator of the mission. "Infrared technology has come a long way since then. The old all-sky infrared pictures were like impressionist paintings -- now, we'll have images that look like actual photographs."

At liftoff, the main Delta II engine and three solid-motor boosters will ignite, providing a total liftoff thrust of more than 1,812,000 newtons (407,000 pounds). The rocket will tilt toward the south, cross the California coastline and head out over the Pacific Ocean. At one minute and 39 seconds after launch, the three spent boosters will fall away from the rocket. Two minutes and 45 seconds later, the main engine will cut off, and 14 seconds later, the vehicle's second stage will ignite. At four minutes and 56 seconds after liftoff, the "fairing" covering the satellite will split open like a clamshell and fall away.

The second stage of the rocket will then cut off, reigniting again 52 minutes after launch. It will shut down a second time and then, at about 55 minutes after launch, the spacecraft will reach its final orbit and separate from the rocket. Engineers expect to pick up a signal from WISE anywhere from about one to 10 minutes after separation.

The next major event will occur about 20 minutes after separation -- the valves on the spacecraft's cryostat will automatically open. The cryostat houses and chills the telescope and infrared detectors with tanks of frozen hydrogen. Valves on the cryostat are opened after launch to allow boiled-off hydrogen to escape, thereby preventing the instrument from warming up.

"It is important to relieve the pressure due to the warming hydrogen as soon as possible," said William Irace, the mission's project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "By venting the hydrogen to space, we cool our instrument down to extremely low temperatures so that the eyes of WISE won't be blinded by their own heat."

After the spacecraft is checked out and calibrated, it will begin the task of surveying the whole sky. This will take about six months, after which the spacecraft will begin to sweep the sky a second time, covering about one-half before the frozen coolant runs out. The mission's primary lifetime is expected to be about 10 months.

The closest of the mission's finds will be asteroids and comets with orbits that come relatively close to Earth's path around the sun. These are called near-Earth objects. The infrared explorer will provide size and composition information about hundreds of these objects, giving us a better idea of their diversity. How many are dark like coal, and how many are shiny and bright? And how do their sizes differ? The mission will help answer these questions through its infrared observations, which provide information that can't be obtained using visible-light telescopes.

"We can help protect our Earth by learning more about the diversity of potentially hazardous asteroids and comets," said Amy Mainzer, deputy project scientist for the mission at JPL.

The farthest of the mission's targets are powerful galaxies that are either churning out loads of new stars or dominated by voracious black holes. These galaxies are shrouded in dust, and often can't be seen in visible light. WISE will expose millions, and may even find the most energetic, or luminous, galaxy in the universe.

"WISE can see these dusty objects so far away that we will be looking back in time 10 billion years, when galaxies were forming," said Peter Eisenhardt, the mission's project scientist at JPL. "By scanning the entire sky, we'll learn just how extreme this galaxy formation process can get."

JPL manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The mission's principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

More information is online at http://www.nasa.gov/wise, http://wise.astro.ucla.edu and http://www.jpl.nasa.gov/wise.

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov

2009-188

Source: NASA - Missions - WISE - News & Media Resources

[Waspie_Dwarf]

WISE Prelaunch News Conference 12/9/09

09 December 2009

After launch, WISE will scan the entire sky in infrared light with a sensitivity hundreds of times greater than ever before, picking up the glow of hundreds of millions of objects and producing millions of images. The mission will uncover objects never seen before, including the coolest stars, the universe's most luminous galaxies and some of the darkest near-Earth asteroids and comets.

Source: NASA Channel - YouTube

[Waspie_Dwarf]

WISE Mission Science Briefing 12/9/09

09 December 2009

After launch, WISE will scan the entire sky in infrared light with a sensitivity hundreds of times greater than ever before, picking up the glow of hundreds of millions of objects and producing millions of images. The mission will uncover objects never seen before, including the coolest stars, the universe's most luminous galaxies and some of the darkest near-Earth asteroids and comets.

Source: NASA Channel - YouTube

[Waspie_Dwarf]

WISE Launch Delayed 24 Hours

12.10.09

WISE is shown inside one-half of the nose

cone, or fairing, that will protect it during

launch. The spacecraft is clamped to the top

of the rocket above the white conical fitting.

The fairing will split open like a clamshell

about five minutes after launch.

Credit: United Launch Alliance/JPL-Caltech

› Larger image

Liftoff of a Delta II rocket and its NASA payload, the Wide-field Infrared Survey Explorer (WISE), has been delayed 24 hours. At the soonest, launch now will be Saturday, Dec. 12, during a launch window that extends from 6:09:33 to 6:23:51 a.m. PST (9:09:33 to 9:23:51 a.m. EST).

The delay allows the launch team additional time to troubleshoot a technical issue. During final systems checks of the Delta II rocket Wednesday in preparation for flight, an anomaly in the motion of a booster steering engine was detected.

The weather forecast for Dec. 12 calls for thick clouds, disturbed weather and precipitation, resulting in an 80 percent chance of conditions preventing liftoff.

Launch and mission managers will discuss the weather and liftoff status during meetings today. Updates to the WISE mission status will be issued as new information becomes available.

The WISE spacecraft will circle Earth over the poles, scanning the entire sky one-and-a-half times in nine months. The mission will uncover hidden cosmic objects, including the coolest stars, dark asteroids and the most luminous galaxies.

More information is online at http://www.nasa.gov/wise, http://wise.astro.ucla.edu and http://www.jpl.nasa.gov/wise.

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov

2009-190

Source: NASA - Missions - WISE - News & Media Resources

[Waspie_Dwarf]

WISE Launch

Spacecraft: Wide-field Infrared Survey Explorer (WISE)

Launch Vehicle: United Launch Alliance Delta II 7925

Launch Site: Vandenberg Air Force Base - SLC 2

Launch Date: Dec. 14, 2009

Launch Time: 6:09:33 - 6:23:51 a.m. PST (9:09:33 - 9:23:51 a.m. EST)

New Launch Date for WISE

Image above: Installation of the Delta II payload fairing

around NASA's Wide-field Infrared Survey Explorer, or WISE,

is under way in the White Room at Space Launch Complex 2

at Vandenberg Air Force Base in California.

NASA/VAFB

› View High-res

12/10/2009: Liftoff of a Delta II rocket and its NASA payload, the Wide-field Infrared Survey Explorer (WISE), is rescheduled to Monday, Dec. 14. Liftoff is targeted for 6:09:33 a.m. PST (9:09 a.m. EST).

The delay was due to an anomaly in the motion of a booster steering engine. Mission managers have implemented a plan to remove and replace a suspect component on Friday.

WISE: Mapping the Infrared Sky

From a vantage point 500 km above Earth's surface, WISE will survey the entire sky at infrared wavelengths, creating a cosmic clearinghouse of hundreds of millions of objects that will be catalogued and provide a vast storehouse of knowledge about the solar system, the Milky Way, and the universe. By the end of its six-month mission, WISE will have taken nearly 1,500,000 pictures covering the entire sky

Source: NASA - WISE - Launch

Edited December 11, 2009 by Waspie_Dwarf

[Waspie_Dwarf]

WISE Webcast

11 December 2009

Go behind the scenes to see how the Delta II rocket and the WISE space telescope are prepared for launch on this exciting mission to view space through infrared eyes.

Source: NASA Channel - YouTube

[Waspie_Dwarf]

Spacecraft and Instruments

Spacecraft

The WISE science instrument.

Image credit: NASA

› Full image and caption

The WISE spacecraft is about the height and weight of a big polar bear, only wider. It measures 2.85 meters tall (9.35 feet), 2 meters wide (6.56 feet), 1.73 meters deep (5.68 feet) and weighs 661 kilograms (1,433 pounds). It is composed of two main sections: the instrument and the spacecraft bus.

The Space Dynamics Laboratory in Logan, Utah, designed, fabricated and tested the instrument. They also manufactured the electronics used to control the instrument and perform onboard processing of the detector images.

The spacecraft bus was built by Ball Aerospace & Technologies Corp, Boulder, Colo. Ball was also responsible for integrating the instrument to the spacecraft bus and testing the completed spacecraft.

The instrument includes a 40-centimeter-diameter (16-inch) telescope and four infrared detectors containing one million pixels each, all kept cold inside an outer cylindrical, vacuum-tight tank filled with frozen hydrogen, called a cryostat. Some say the whole assembly looks like a giant Thermos bottle, while others see a resemblance to the Star Wars robot R2-D2. After launch, the hydrogen vents on the cryostat are opened and the instrument cover is ejected. Once these events have occurred, a scan mirror in the telescope will be the only moving instrument part.

At the bottom of the instrument is a three-axis stabilized, eight-sided spacecraft bus that houses the computers, electronics, battery and reaction wheels needed to keep the observatory operating and oriented correctly in space. Two star trackers for precision pointing are mounted on the sides of the spacecraft bus. A fixed solar panel that provides all the spacecraft's power is mounted on one side of the bus, and a fixed high gain antenna for transmitting science images to the ground is mounted on the opposite side. The bus structure is composed of an aluminum skin backed by aluminum honeycomb panels. It has no deployable parts -- the only moving parts are four reaction wheels used to maneuver the satellite.

The base of the spacecraft structure includes a “soft-ride” system of springs to reduce stress from the rocket on the satellite. A metal clamp band attaches the second stage of the rocket to the base of the satellite, and is released to allow the spacecraft to separate from the launch vehicle in orbit.

---

Science Instrument

Telescope

The WISE telescope has a 40-centimeter-diameter (16-inch) aperture and is designed to continuously image broad swaths of sky at four infrared wavelengths as the satellite wheels around Earth. The four wavelength bands are 3.4, 4.6, 12 and 22 microns. The field of view is 47-arcminutes wide, or about one-and-a-half times the diameter of the moon.

The telescope was built by L-3 SSG-Tinsley in Wilmington, Mass. Its design uses a total of 10 curved and two flat mirrors, all made of aluminum and coated in gold to improve their ability to reflect infrared light. Four of the mirrors form an image from the 40-centimeter primary mirror onto the flat scan mirror. The scan mirror moves at a rate that exactly cancels the changing direction of the spacecraft on the sky, allowing freeze frame images to be taken every 11 seconds. The scan mirror then snaps back to catch up with the craft as it continues to survey the sky.

The remaining mirrors form a focused image of the sky onto the detector arrays. Before reaching the arrays, the light passes through a series of flat "dichroic" filters that reflect some wavelengths and transmit others, allowing WISE to simultaneously take images of the same part of the sky at four different infrared wavelengths.

The image quality, or resolution, of WISE is about six arcseconds in its 3.4, 4.6 and 12 micron bands, meaning that it can distinguish features one six-hundredth of a degree apart. At 22 microns, the resolution is 12 arcseconds, or one three-hundredth of a degree. This means WISE can distinguish features about five times smaller than the Infrared Astronomical Satellite could at 12 and 25 microns, and many hundred times smaller than NASA's Cosmic Background Explorer could at 3.5 and 4.9 microns.

Detectors

Light gathered by WISE's telescope is focused onto what is called a focal plane, which consists of four detector arrays, one for each infrared wavelength observed by WISE. Each of the detector arrays contain about one million pixels (1,032,256 to be exact). This is a giant technology leap over past infrared survey missions. The Infrared Astronomical Satellite's detectors contained only 62 pixels in total.

The 3.4- and 4.6-micron detectors convert light to electrons using an alloy made of mercury, cadmium and tellurium. The electrons from each of the million-plus pixels are measured on the spot every 1.1 seconds, and the result sent to the instrument electronics. These detector arrays, a type known as the HAWAII 1RG, were manufactured by Teledyne Imaging Systems, Camarillo, Calif. They need to be warmer than the rest of the instrument to improve their performance. The 12- and 22-micron detectors sense light using silicon mixed with a tiny amount of arsenic. They have readout electronics specially developed for the low-temperatures of WISE and were manufactured by DRS Sensors & Targeting Systems, Cypress, Calif.

Cryostat

Because WISE is designed to detect infrared radiation from cool objects, the telescope and detectors must be kept at even colder temperatures to avoid picking up their own signal. The WISE telescope is chilled to 12 Kelvin (minus 261 degrees Celsius or minus 438 degrees Fahrenheit) and the detectors for the 12- and 22-micron detectors operate at less than 8 Kelvin (minus 265 degrees Celsius or minus 447 degrees Fahrenheit). The shorter wavelength 3.4- and 4.6-micron detectors operate at a comparatively balmy 32 Kelvin (minus 241 degrees Celsius or minus 402 degrees Fahrenheit). To maintain these temperatures, the telescope and detectors are housed in a cryostat, essentially a giant Thermos bottle.

The WISE cryostat, manufactured by Lockheed Martin Advanced Technology Center, Palo Alto, Calif., has two tanks filled with frozen hydrogen. The colder, or primary cryogen tank, the smaller of the two tanks, cools the 12- and 22-micron detector arrays. To achieve this low operating temperature, a larger 12-Kelvin secondary tank protects the primary tank from nearly all the heat from the outer structure of the cryostat, which is comparatively warm at about 190 Kelvin (minus 83 degrees Celsius or minus 117 degrees Fahrenheit). This secondary tank also cools the telescope and the 3.4- and 4.6-micron detectors. Small heaters are used to warm the 3.4- and 4.6-micron detectors from 12 to 32 Kelvin.

It is important to maintain a vacuum inside the cryostat when it is cold and on the ground; otherwise air would freeze inside it. It would become a giant popsicle. A deployable aperture cover seals the top of the cryostat while on the ground to prevent air from getting in. After WISE is safely in orbit, a signal is sent to eject the aperture cover. Three pyrotechnic separation nuts will fire, and the cover will be pushed away from the spacecraft.

An aperture shade is mounted at the top of the telescope to shield the open cryostat system from the sun and Earth's heat.

The expected lifetime of WISE’s frozen hydrogen supply is 10 months. Since it takes WISE six months to survey the sky, this is enough cryogen to complete one-and-a-half surveys of the entire sky after a one-month checkout period in orbit.

Source: NASA - WISE - Spacecraft & Instruments

[Waspie_Dwarf]

Latest News

WISE Launch Moves to Monday, Dec. 14

Image above: A Delta II rocket is set to launch with NASA's

Wide-field Infrared Survey Explorer from Vandenberg Air

Force Base, Calif.

Image credit: NASA/VAFB

The launch of NASA’s Wide-field Infrared Survey Explorer (WISE) mission is now rescheduled for Dec. 14, with a launch window of 6:09-6:23 a.m. PST (9:09:33 - 9:23:51 a.m. EST). The first launch attempt scheduled for Dec. 11 was delayed due to an anomaly in the motion of a booster steering engine.

Mission managers have implemented a plan to completely resolve the anomaly. This plan includes removing and replacing a suspect component on Friday, Dec. 11 allowing the Delta II to be ready for Monday’s launch attempt. The current weather forecast calls for an 80 percent chance of acceptable weather during the launch window.

The WISE spacecraft will circle Earth over the poles, scanning the entire sky one-and-a-half times in nine months. The mission will uncover hidden cosmic objects, including the coolest stars, dark asteroids and the most luminous galaxies.

Source: NASA - Missions - WISE

[thefinalfrontier]

Good thing they found the issue beforehand,

Edited December 12, 2009 by thefinalfrontier