James Webb Space Telescope undergoes final tests

The James Web Space Telescope (JWST), the world’s largest space telescope, is to undergo final tests inside Chamber A at NASA’s Johnson Space Center in Houston, to make sure it functions properly in outer space. The James Webb Space Telescope, part of NASA’s ongoing Flagship program, and developed in cooperation with the Canadian Space Agency and the European Space Agency, is scheduled to launch in October next year.

The James Webb Space Telescope will soon be literally ‘hanging out’ in a vibrations-isolating ‘hammock’ – six support rods attached to the platform on which the telescope is sitting – at extremely low temperatures.

The hammock isolates the telescope from vibrations that Chamber A might produce as soon as the door shuts and testing starts, as well as from disturbances that may occur outside the chamber.

James Webb Space Telescope designed for space

Gary Matthews, a testing and integration engineer at NASA’s Goddard Flight Center, Greenbelt, Maryland, who is testing the James Webb Telescope at Johnson, said:

“Remember that the system is designed to work in space, where the disturbances are highly controlled and only come from the spacecraft.”

“On Earth, we have to deal with all the ground-based disturbances, such as the pumps and motors, and even traffic driving by.”

James Webb Space Telescope - suspendedThe James Webb Space Telescope hanging from the ceiling of Chamber A at NASA’s Johnson Space Center in Houston, Texas. (Image: nasa.gov. Credit: NASA/Chris Gunn)

In NASA’s photograph, viewers may have a hard time seeing the telescope floating, because it is suspended just a few inches from the rails at the bottom of Chamber A. The rails were used to roll it into place.

Cryogenic testing phase

With the telescope suspended in the hammock, engineers carried out a push test, where they gave it a gentle nudge and monitored its reaction to ensure the suspension system was working properly.

During what the engineers call the **Cryogenic Testing Phase, the Webb James Space Telescope will be inside Chamber A for approximately three months.

**Cryogenic means involving or using an extremely low temperature.

In space, it must be kept extremely cold, so that it can detect infrared light from very faint distant celestial objects. A five-layer, tennis court-sized sun-shield protects the telescope from external sources of heat and light, like the Sun, Moon and Earth, as well as from heat that the observatory emits.

James Webb Space Telescope - Artist impressionThe James Webb Space Telescope originated in 1996 as the NGST (Next Generation Space Telescope). NASA renamed it in 2002 after James E. Webb (1906-1992), NASA’s second administrator, noted for playing a crucial role in the Apollo program. (Image: flickr.com/photos/nasawebbtelescope)

The James Webb Space Telescope will be in an environment where temperatures range from 185 degrees Fahrenheit to 400 degrees below zero.

The sun-shield blocks sunlight, which can distort the sensitive instruments’ readings.

According to NASA:

“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, ESA (European Space Agency) and the Canadian Space Agency.”

About the James Webb Space Telescope

The James Webb Space Telescope will be a huge infrared telescope with a 6.5-meter primary mirror. It will be launched on an Ariane 5 rocket in October 2018 from French Guiana.

According to NASA:

“JWST will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.”

The whole project is an international collaboration between NASA, ESA (European Space Agency), and CSA (Canadian Space Agency).

NASA’s Goddard Space Flight Center is managing the telescope’s development effort. The Space Telescope Science Institute will operate JWST when it is in space.

James Webb Space Telescope - scientific instrumentsThe telescope has the following instruments: 1. MIRI (Mid-Infrared Instruments), provided by the European Consortium with ESA, and by JPL (NASA’s Jet Propulsion Laboratory). 2. FGS (Fine Guidance Sensor), also NIRISS (Near InfraRed and Slitless Spectrograph), provided by the Canadian Space Agency. 3. NIRCam (Near-Infrared Camera), provided by the University of Arizona. 4. NIRSpec (Near-Infrared Spectograph), provided by ESA, with components provided by NASA/GSFC. (Image: adapted from jwst.nasa.gov)

A number of innovative technologies have been developed specifically for JWST. These include:

– A primary mirror comprising 18 different segments that unfold and adjust to shape after the telescope has been launched. They are made of ultra-lightweight beryllium.

– A tennis court-sized, 5-layer sun-shield that reduces the heat from the Sun to one-millionth of what it was.

– Its four instruments – spectrometers and cameras – have detectors that can record extremely faint signals. One instruments, called NIRSPEC, has programmable microshutters, which make it possible to observe up to one hundred objects, all at the same time.

– It also has a cryocooler for cooling the mid-infrared detectors of the MIRI, another instrument, to an extremely cold 7 K so they can work.

NASA scientists hope that the James Webb Space Telescope will be able to use it infrared vision to confirm plume activity or venting on Europa, one of Jupiter’s moons.

Video – James Web Space Telescope

This NASA video shows how two dozen technicians and engineers successfully installed the package of state-of-the art scientific instruments into the James Webb Space Telescope’s  structure.

The ISIM (Integrated Science Instrument Module) contains a collection of spectrographs, cameras, and fine guidance systems that help record the light collected by the telescope’s giant golden mirror.