The James Webb Space Telescope will experience intense forces as it launches into space. To ensure that the different parts of the observatory won't suffer damage during this stage of the mission, engineers shake them rigorously. These two- to three-week-long vibration tests are performed on each of Webb's 18 primary mirror segments and the secondary, tertiary, and fine-steering mirrors. Engineers test the mirror's optics before and after each vibration test to confirm that the simulated launch left the mirror surface unscathed, without deformation or structural changes.

The many components of the James Webb Space Telescope undergo testing at their place of construction, as well as at the locations where the individual pieces are assembled into larger parts. But closer to launch, engineers need to put the fully-assembled telescope through environmental testing. NASA will be using its largest thermal vacuum chamber to accomplish this task. The chamber at Houston's Johnson Space Center was used to test Apollo vehicles back in the 60's and 70's, and has been used sporadically throughout the following years for other space vehicles. Changes are being made to the chamber so the James Webb Space Telescope can be tested even more rigorously than the Apollo spacecraft.

Related outside links:

NASA information about Johnson Space Center's Chamber A

The making of Webb's mirrors is a complex process. It requires painstaking work to fine-tune each surface to capture and direct the maximum amount of light to the telescope's detectors. The mirrors must be ground and polished to a precise, smooth curve that keeps light from bouncing off in unwanted directions. At Tinsley Laboratories in Richmond, Calif., engineers are shaping Webb's mirrors to their exact requirements.

The primary mirror segments of the Webb Telescope, along with its secondary and tertiary mirrors, are not made of glass like most mirrors on Earth. They are made of beryllium, a relatively rare metal that is only mined and processed in one place in the western hemisphere. Behind the Webb's Mary Estacion travels to the West Desert of Utah to take a look at what it takes to extract this unique ore.

Get the details on the rare metal beryllium, why its properties make it perfect for Webb's mirrors, and the complex process that changes it from raw ore into a precise astronomical tool. Read the NASA feature article, The "Not So Heavy Metal Video": James Webb Space Telescope's Beryllium Mirrors

One of the dominant features of the Webb telescope is its tennis court-sized sunshield. The sunshield protects the observatory from unwanted light, keeping it cool and allowing it to detect heat from faraway objects in the universe.

Getting such a huge sunshield into orbit, however, is a technical feat. Webb's sunshield will be folded up during launch, and then unraveled in a seven-hour deployment process as the Webb telescope reaches its destination a million miles from Earth. Two deployable towers, or Mid Boom Assemblies (MBA), serve to stretch the sunshield open. The completion of this hour-long process triggers another mechanism that separates the sunshield's five layers, readying the sunshield for work.

Read a feature article about Webb's sunshield at NASA.gov.

Webb has a primary mirror six times larger than the one found on the Hubble Space Telescope. In order for a primary mirror 21 feet in diameter to travel into space, it has to be broken up into multiple segments in this case, 18 of them.

But for the 18 to act as one primary mirror, they have to be adjusted while in orbit. How this task is achieved is the focus of this episode of Behind the Webb: Got Your Back.

Webb's orbit will place it out of reach of repair crews. The telescope will be located beyond the Moon, so far away even astronauts would be unable to access it. Ensuring perfect control of the telescope from the confines of Earth is vital.

At Northrop Grumman, engineers are testing the telescope's responses to its controllers and performing simulations of the conditions it would face in orbit. Making sure the telescope works on the ground is critical to guaranteeing it'll work in space.

The Webb Space Telescope model rose into the sky, enticing viewers with its promise of new cosmic wonders. At the World Science Festival in New York City, the life-sized model was a draw for both the technologically inclined and scientifically curious. While telescope experts and astronomers gave a rundown of Webb's capabilities, visitors explored the promise of the next big leap in orbiting observatories. Webb's enormous size and distant orbit will allow it to see infrared light with a previously unachieved clarity, opening the path to new visions of the universe.

Credit: Space Telescope Science Institute; Mike McClare, NASA GSFC.

Outside related links:

The World Science Festival

Time-lapse videos of the model being built in Battery Park

More pictures of the Webb Telescope model

Webb's mirrors capture and direct light from the distant universe to create the telescope's images. Webb's primary mirror - with its vast expanse made up of 18 segments - gets most of the attention, but several more mirrors help control the flow of light through the telescope. Webb has a secondary, tertiary and fine-steering mirror, each appropriately shaped for the action it must undertake. The mirrors' ultimate goal is to get the light to the telescope's detectors in order to record and translate it into imagery.

Outside related links:

Basic science concepts about how telescopes work from Amazing Space

Universe Today's guide to reflecting telescopes

Wikipedia's entry about Reflecting Telescopes

The James Webb Space Telescope will see infrared light, which humans perceive as heat. In order to work properly, the telescope has to be kept very cold. Engineers have designed a huge sunshield to block heat from the Sun, allowing Webb to operate at nearly -400 degrees Fahrenheit. The telescope will be cold enough to let astronomers measure the infrared from far away objects in the universe.

Engineers at Northrup Grumman in Redondo, Beach, Calif., designed Webb's sunshield. It consists of five layers of a space-age material called Kapton. Each layer is only about as thick as a human hair, but has to be strong enough to withstand the harsh environment of space. The orientation of these layers also help dissipate any incoming heat before it has a chance to affect the telescope. The sheets of the sunshield will be coated with different materials, depending upon their position. The two layers exposed to the sun will be coated with silicon to reflect the sun's energy. The remaining three layers will be coated with aluminum to reflect any residual heat that the first two layers were unable to dissipate.

Related links:

Challenge: Keep It Cold - How the Webb Telescope is chilled.

Outside links:

NASA news feature: Super-Tough Sunshield to Fly on the James Webb Space Telescope

NASA news release: Sunshield Preliminary Design Review Complete

The digital camera in your home shares a family tree with the James Webb Space Telescope. Webb's instruments use "detectors," similar to the sensors in digital cameras, to convert images into a digital signal.

The detectors being tested at the Jet Propulsion Laboratory in Pasadena, Calif., are part of the Mid-Infrared Instrument (MIRI). The detectors, which will be housed in insulated, brick-like structures called focal plane modules, go through intensive temperature and vibration testing to ensure they survive the ride into orbit. The detectors have to be perfectly aligned within these brick structures, so they don't move out of position when the chill of space causes materials to shrink. MIRI will be the most sensitive mid-infrared instrument ever flown in space, helping us see deeper into the universe than ever before.

Related links:

Techonology Overview: Instruments

Outside links:

NASA's Webb instruments page

Images of Webb's detectors

NASA news feature: James Webb Space Telescope Testing to Find Infrared Light for Christmas

NASA news feature: Shake, Rattle and Roll: James Webb Telescope Components Pass Tests