Like a beach umbrella protects people from the sun's heat and ultraviolet radiation, the sunshield protects the telescope and the sensitive infrared instruments that fly beneath the Webb telescope's sunshield from our sun's heat and light. "Each of the five layers of the shield is less than half the thickness of a piece of paper. The five work together to create an effective SPF (or Sun Protection Factor) of 1,000,000," said John Durning, Deputy Project Manager for the James Webb Space Telescope Project, at NASA's Goddard Space Flight Center, Greenbelt, Md.
A new video takes viewers to Northrop Grumman's Astro Aerospace in Carpinteria, Calif. to understand the mechanics necessary to unfold the large tennis-court sized sunshield. In the 3:00 minute video, engineers are interviewed to explain how the new technology extends the sunshield in space and unfurls it before the Webb telescope attains orbit one million miles from Earth.
The video called "Stretching Webb's Wings" is part of an on-going video series about the Webb telescope called "Behind the Webb." It was produced at the Space Telescope Science Institute (STScI) in Baltimore, Md. and takes viewers behind the scenes with scientists and engineers who are creating the Webb telescope's components.
The large sunshield is 20 meters (65.6 ft.) by 12 meters (39.3 ft.). It is made of a material called Kapton that can be folded like a blanket. Kapton is a film developed by DuPont which can remain stable and strong over the wide range of temperatures, from 36K to 650 Kelvin (K) (-395°F to 710°F or -237 to 377°C), the sunshield will experience during its launch and deployment. Once on orbit, the sunshield creates a 330 K (243°F to -351°F) temperature differential between the hottest and coldest layers. Using multiple separated layers allows most of a layer’s heat to radiate to space before it reaches the next one creating a substantial temperature drop from one layer to the next.
The Kapton membranes used on the Webb telescope are coated with infrared-reflecting aluminum. The lowest two sun facing sunshield layers are coated with a silicon-based conductive coating to prevent the buildup of an electric charge, and minimize the amount of absorbed heat from the sun.
When the sunshield is folded up, it is packaged on a large pallet. A boom system being developed at Northrop Grumman Astro-aerospace in Galita, Calif. pulls each side of the sunshield from the pallet. It deploys much like a telescoping radio antenna, or like a big beach umbrella that extends upward and pops into place.
Each of the sunshield's five layers are unfurled and separated out in space to resemble a giant umbrella by spreader bars and cable drives. There are two electrical motor mechanisms called stem deployers, one on each side of the spacecraft. Their job is to "push out" from the inside, the telescoping booms thus pulling out the folded up membranes on each side. "The stem deployer extends the telescoping boom," said Mark Clampin, James Webb Observatory Project Scientist at NASA Goddard. "The metaphor that comes to mind is a sailing boat, except that the sail (membrane) would have to be raised by a telescoping main mast, rather than hoisted up the main mast."
The James Webb Space Telescope will observe primarily the infrared light from faint and very distant objects. But all objects, including telescopes, also emit infrared light in the form of heat energy. To avoid swamping the very faint astronomical signals with radiation from the telescope and the telescope from seeing its own thermal signature, the telescope and its instruments must be very cold, at an operating temperature of under 50 K (-370F/-223C).
The observatory will be pointed so that the Sun, Earth and Moon are always on one side, and the sunshield will act like a beach umbrella, keeping the Optical Telescope Element and the Integrated Science Instrument Module on the telescope's topside cool by keeping them in the shade and protecting them from the heat of the sun and warm spacecraft electronics. The telescope is on the topside and the underside sees the sun.
The Webb telescope will orbit 1,513,000 km (940,000 miles) from Earth at the L2 Lagrange point and is the first deployable optical telescope in space. It will undergo a complex post-launch sequence of deployments including the sunshield, before it becomes fully operational.
The video "Stretching Webb's Wings" will give viewers a unique behind the scenes look at the equipment that will make the sunshield expand almost a million miles from Earth.
The "Behind the Webb" video series is available in HQ, large and small Quicktime formats, HD, Large and Small WMV formats, and HD, Large and Small Xvid formats.To see the sunshield deployment in this new "Behind the Webb" video, visit:
Lynn Chandler | EurekAlert!
A single photon reveals quantum entanglement of 16 million atoms
16.10.2017 | Université de Genève
On the generation of solar spicules and Alfvenic waves
16.10.2017 | Instituto de Astrofísica de Canarias (IAC)
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
It's possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF...
Mercury, our smallest planetary neighbor, has very little to call an atmosphere, but it does have a strange weather pattern: morning micro-meteor showers.
Recent modeling along with previously published results from NASA's MESSENGER spacecraft -- short for Mercury Surface, Space Environment, Geochemistry and...
10.10.2017 | Event News
10.10.2017 | Event News
28.09.2017 | Event News
16.10.2017 | Physics and Astronomy
16.10.2017 | Earth Sciences
16.10.2017 | Physics and Astronomy