Spoiler for bacaanNASA's Webb Telescope Pathfinder Telescope Fully Assembled
Inside a giant clean room at NASA's Goddard Space Flight Center in Greenbelt, Maryland, the pathfinder telescope, a practice section of the James Webb Space Telescope, stands fully assembled. Teams of engineers built and aligned the pathfinder telescope to rehearse assembly and testing before the actual telescope is built. After the team installs the test sensors and completes their final close out, the pathfinder telescope will be shipped to NASA's Johnson Space Center in Houston, Texas for cryo-optical testing.
Text credit: NASA/Laura Betz
Image credit: NASA/Chris Gunn
Spoiler for bacaanWebb Telescope Mirrors: Stepping Stones to the Cosmos
Scientists and engineers placed two NASA James Webb Space Telescope test primary mirror segments onto the support structure that will hold them, where they resemble stepping stones, as seen in this photo.
There are four types of mirrors that will fly aboard NASA's James Webb Space Telescope: The primary, secondary, tertiary and fine steering mirrors.
Together they will direct light into sensitive instruments, like stepping stones towards new discoveries about the cosmos.
Highly trained engineers and technicians from NASA, Exelis, and Northrop Grumman lifted the two test primary mirror segments in the photograph onto the support structure, working in a giant clean room at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Both mirrors are made from beryllium. These primary mirror "test" segments are also flight spares. One of the mirrors is coated with a microscopically fine film of gold just like the actual flight mirrors, while the other is not. For the testing these mirrors willundergo, it is not critical that they all be gold-coated. The gold coating will enable the mirrors to most efficiently reflect the infrared light from distant galaxies.
"The gold-coated mirror is the engineering development unit and is a fully finished flight spare and is ready to fly if necessary, while the other is an almost-but-not-quite finished spare that needs a final round of polishing, cryotesting, or testing at freezing temperatures to simulate space, and gold coating, before it can be flown," said Paul Geithner, deputy project manager - technical for the Webb telescope at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
Ball Aerospace & Technologies Corp. in Boulder, Colorado built the mirrors. Ball is the principal subcontractor to Northrop Grumman for the optical technology and lightweight mirror system. Ball Aerospace also developed the secondary mirror, tertiary mirror and fine-steering mirror.
As the premier observatory for the next decade, the Webb telescope will be stationed 1 million miles (1.5 million km) from Earth â€" some four times farther away from us than the moon. Webb will be the most powerful space telescope ever built, able to detect the light from the first galaxies ever formed and explore planets around distant stars. It will study every phase of our universe's history, ranging from the first luminous glows after the Big Bang, to the formation of planetary systems capable of supporting life on planets like Earth, to the evolution of our own solar system.
The Webb telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.
For more information about the Webb telescope, visit: www.jwst.nasa.gov or www.nasa.gov/webb
Photo credit: NASA/Chris Gunn
Spoiler for bacaanJames Webb Space Telescope's Heart Survives Deep Freeze Test
After 116 days of being subjected to extremely frigid temperatures like that in space, the heart of the James Webb Space Telescope, the Integrated Science Instrument Module (ISIM) and its sensitive instruments, emerged unscathed from the thermal vacuum chamber at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
The Webb telescope's images will reveal the first galaxies forming 13.5 billion years ago. The telescope will also pierce through interstellar dust clouds to capture stars and planets forming in our own galaxy. At the telescope's final destination in space, one million miles away from Earth, it will operate at incredibly cold temperatures of -387 degrees Fahrenheit, or 40 degrees Kelvin. This is 260 degrees Fahrenheit colder than any place on the Earth’s surface has ever been. To create temperatures that cold on Earth, the team uses the massive thermal vacuum chamber at Goddard called the Space Environment Simulator, or SES, that duplicates the vacuum and extreme temperatures of space. This 40-foot-tall, 27-foot-diameter cylindrical chamber eliminates the tiniest trace of air with vacuum pumps and uses liquid nitrogen and even colder liquid helium to drop the temperature simulating the space environment.
The James Webb Space Telescope is the scientific successor to NASA's Hubble Space Telescope. It will be the most powerful space telescope ever built. Webb is an international project led by NASA with its partners, the European Space Agency and the Canadian Space Agency.[/color]
James Webb Space Telescope Sunshield Test Unfolds Seamlessly
A major test of the sunshield for NASA’s James Webb Space Telescope was conducted recently by Northrop Grumman in Redondo Beach, California. For the first time, the five sunshield test layers were unfolded and separated; unveiling important insights for the engineers and technicians as to how the deployment will take place when the telescope launches into space.
“These tests are critical and allow us to see how our modeling works and learn about any modifications we may need to make in our design as we move into sunshield flight production,†said Jim Flynn, Webb sunshield manager.
The three-day test took place in July, taking seven engineers and six technicians about 20 hours to complete. On orbit, the sunshield will take several days to unfold.
“Tests on the ground are a little bit tricky because we have to account for gravity,†says Flynn. “Webb won’t face those same challenges in space. To overcome challenges on the ground, our technicians came up with the idea to rest the layers on a structure of metal beams covered by plastic.â€
The tennis court-sized sunshield, which is the largest part of the observatory, will be folded up around the Webb telescope’s mirrors and instruments during launch. As the telescope travels to its orbit one million miles from Earth, it will receive a command to unfold and separate the sunshield's five layers into their precisely stacked arrangement with its kite-like shape.
The sunshield separates the observatory into a warm, sun-facing side (reaching temperatures close to 400 degrees Farenheit), and a cold side (185 degrees below zero) where the sunlight is blocked from interfering with the sensitive telescope instruments. It provides the instruments with an effective sun protection factor, or SPF, of one million.
The sunshield’s membrane layers, each as thin as a human hair, are made of Kapton, a tough, high-performance plastic coated with a reflective metal. On orbit, the observatory will be pointed so that the sun, Earth and moon are always on one side, with the sunshield acting as an umbrella to shade the telescope mirrors and instruments from the warmer spacecraft electronics and the sun.
Northrop Grumman subcontractor NeXolve is currently manufacturing the flight sunshield layers at their facilities in Huntsville, Ala. The five flight layers will be delivered to Northrop Grumman in 2016, when extensive testing will continue, followed by integration with the entire observatory.
Image Credit: Northrop Grumman/Alex Evers
Spoiler for bacaanJames Webb Space Telescope's "Mirror Mattress"
The backplane of NASA's James Webb Space Telescope looks like the springs in a mattress. In this photo, you see the central part of the three-part backplane, tilted to its side, much like a mattress being carried.
Eighteen hexagonal polished metal segments that together comprise the largest mirror on the Webb telescope will rest on the backplane.
This is the center section of the actual backplane that will fly on the Webb telescope. The backplane also has two "wings" or other sections that attach to each side. The photograph was taken at Northrop Grumman's clean room in Redondo Beach, California.
The Webb's giant mirrors will collect light from galaxies farther away and further back in time than ever seen before.
The James Webb Space Telescope is the successor to NASA's Hubble Space Telescope. It will be the most powerful space telescope ever built. Webb is an international project led by NASA with its partners, the European Space Agency and the Canadian Space Agency.
Learn more about the Webb telescope at: www.jwst.nasa.gov or www.nasa.gov/webb
Text credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, Maryland
Image credit: Chris Gunn, NASA's Goddard Space Flight Center, Greenbelt, Maryland
Spoiler for bacaanNASA Engineers Conduct Low Light Test on New Technology for Webb Telescope
NASA engineers inspect a new piece of technology developed for the James Webb Space Telescope, the micro shutter array, with a low light test at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Developed at Goddard to allow Webb's Near Infrared Spectrograph to obtain spectra of more than 100 objects in the universe simultaneously, the micro shutter array uses thousands of tiny shutters to capture spectra from selected objects of interest in space and block out light from all other sources.
The James Webb Space Telescope is a large space telescope, optimized for infrared wavelengths. It is scheduled for launch later in this decade. Webb will find the first galaxies that formed in the early universe, connecting the Big Bang to our own Milky Way galaxy. Webb will peer through dusty clouds to see stars forming planetary systems, connecting the Milky Way to our own solar system.
Caption Credit: Laura Betz, NASA's Goddard Space Flight Center, Greenbelt, Maryland
Image Credit: NASA Goddard/Chris Gunn
Spoiler for bacaanA "NIRSpec-tacular View" of NASA's Webb Telescope Instrument
Photo Credit: NASA/Chris Gunn
A NASA photographer recently captured a "NIRSpec-tacular" photo of an instrument that will fly aboard NASA's James Webb Space Telescope when it launches in 2018.
Access into a clean room to get a close-up view of a complicated, high-value scientific instrument is carefully controlled, but NASA photographers get such exclusive entry all the time. Photographer Chris Gunn took this image of the NIRSpec instrument inside the giant cleanroom at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
The Near-Infrared Spectrograph or NIRSpec is a multi-object spectrograph, which is a tool for observing many objects in the cosmos simultaneously. The NIRSpec takes in light from around 100 distant objects and records their spectra (band of colors produced when sunlight is passed through a prism), separating the light into its components using prisms and other optical devices.
The NIRSpec will join three other Webb science instruments that will be mounted on the Integrated Science Instrument Module (ISIM). The ISIM structure is like the frame of a in a car providing support for the engine and other components.
In the photo, the NIRSpec is the large silver mass on the right-hand side. The silver frame-like object on the left side is part of the ISIM structure.
The NIRSpec can gather data on over 100 objects at the same time over a 9-square-arcminute field of view (the sun seen from Earth is about 32 arcminutes across). The NIRSpec will be the first spectrograph in space that has this remarkable multi-object technology. To make it possible, Goddard scientists and engineers had to invent a new device using a microshutter system to control how light enters the NIRSpec.
NIRSpec weighs about 430 pounds (195 kg), about as much as an upright piano. It is one of four instruments that will fly aboard the Webb telescope. The other instruments include the Near-Infrared Camera (NIRCam), the Mid-Infrared Instrument (MIRI) and the Fine Guidance Sensor/ Near InfraRed Imager and Slitless Spectrograph (FGS/NIRISS).
The ISIM and NIRSpec are now in a months-long cryo-vacuum test. This test duplicates the vacuum and extreme temperatures of space to ensure that the ISIM and the NIRSpec can function properly in those conditions.
NIRSpec was provided by the European Space Agency and built by Airbus Defense and Space in Germany. Webb is an international project led by NASA with its partners the European Space Agency and the Canadian Space Agency.
For more information about the NIRSpec, visit: http://jwst.nasa.gov/nirspec.html or http://www.nasa.gov/mission_pages/we...s/NIRSpec.html
For a "Behind the Webb" video feature on NIRSpec, visit: http://www.nasa.gov/content/goddard/...oints-of-light
Rob Gutro
NASA's Goddard Space Flight Center[/color]
Sumber :http://www.kaskus.co.id/thread/547cc36a9e74040b408b4568
