The Webb Story: Unfolding Our Cosmic History
Where did we come from?
The greatest origin story of all unfolds with the James Webb Space Telescope. Webb is NASA’s newest premier space science observatory – destined to be a household name, like its predecessor, Hubble. This is an Apollo moment for NASA science: Webb will fundamentally alter our understanding of the universe. It can observe all of the cosmos, from planets to stars to nebulae to galaxies and beyond – helping scientists uncover secrets of the
distant universe as well as exoplanets closer to home. Webb can explore our own solar system’s residents with
exquisite new detail and search for faint signals from the first galaxies ever made. From new forming stars to devouring black holes, Webb will reveal all this and more.
Webb is engineered to build upon the groundbreaking discoveries of other spacecraft, such as the Hubble Space
Telescope and the Spitzer Space Telescope. While Hubble views the universe in visible and ultraviolet light,
Webb focuses on infrared, a wavelength important for peering through gas and dust to see distant objects. After
Spitzer blazed trails in the infrared, Webb will take us farther by virtue of a primary mirror that is nearly 60 times
larger in area. Finally, Webb’s mirror gives us Hubble’s incredible resolution with even greater sensitivity, and it is
fully adjustable in space.
Webb’s large mirror and advanced suite of instruments are protected by a five-layer sunshield, built to unfurl until it reaches the size of a tennis court. The entire observatory is folded up to fit inside the launch vehicle and will unfold in space. This complex deployment sequence has never been attempted for a space telescope, and the amazing engineering that enabled Webb includes many innovations that push the boundaries of technology.
Webb is a feat of human ingenuity. The mission has been developed over two decades, with contributions from
thousands of scientists, engineers, and other professionals from more than 14 countries and 29 U.S. states. Webb’s launch is a pivotal moment that exemplifies the dedication, innovation, and ambition behind NASA and its partners, the European Space Agency (ESA) and Canadian Space Agency (CSA), but it is only the beginning. The observatory’s six months of commissioning in space is an exciting but harrowing time, during which thousands of parts and sequences all have to work correctly together, almost a million miles from Earth. This period culminates when the telescope begins to take data – a truly momentous celebration for the mission,
NASA, the United States, and the world.
Fundamental astronomy questions propelled Webb’s unique design, cutting-edge capabilities, and unparalleled
infrared sensitivity – all geared to provide a new view of the universe and capture our imagination with extraordinary science discoveries. It’s a giant leap forward in our quest to understand humanity’s place in the great cosmic expanse.
History
Since the late 1980s, Webb has evolved from just an idea – “What’s next?” – to a premier flagship mission in 2021.
In 1989, the Space Telescope Science Institute (STScI) in Baltimore, Maryland, and NASA co-hosted the Next Generation Space Telescope Workshop at STScI, where engineers and astronomers debated the science and technical capabilities of an observatory that would follow the Hubble Space Telescope. Discussions from that workshop led to the formal recommendation in 1996 that the telescope should operate in infrared wavelengths and be equipped with a mirror larger than 4 meters.
By 2002, NASA had selected the teams to build the instruments and the group of astronomers who would provide construction guidance. Construction on Webb began in 2004. In 2005, the
European Space Agency’s Centre Spatial Guyanais (CSG) spaceport in French Guiana was chosen as the launch site and an Ariane 5 rocket as the launch vehicle. By 2011, all 18 mirror segments were
finished and proven through testing to meet required specifications.
Between 2012 and 2013, Webb’s individual pieces, constructed in a variety of locations, began to arrive at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. In 2013, construction of the sunshield layers began. From 2013 to 2016, Webb’s science instruments were packaged together and subjected to numerous tests of extreme temperature and vibration.
From late 2015 to early 2016, the telescope optics and structures were assembled, featuring installation
of all 18 of Webb’s individual mirrors on the telescope’s backplane structure to assemble the 21-foot (6.5-meter)
mirror.
In 2017, the telescope assembly and the package of science instruments were integrated into one unit and subjected to mechanical integrity vibration testing at
Goddard, then shipped to NASA’s Johnson Space Center in Houston, Texas, for end-to-end optical performance
testing in a giant cryogenic temperature vacuum chamber.
In 2018, the performance-verified telescope plus instrument assembly was delivered to Northrop Grumman in
Redondo Beach, California, where the spacecraft bus plus sunshield assembly was being built and tested, and
the following year, these two halves of Webb were connected.Final
environmental, electrical, functional, and communications testing continued until Webb was folded and stowed for the final time in 2021.
The James Webb Space Telescope studies every phase of Cosmic Historic
The Webb telescope is the scientific successor to the iconic Hubble and Spitzer space telescopes, built to
complement and further the discoveries of Hubble, Spitzer, and other NASA missions by accessing the near-
infrared and mid-infrared wavelengths with unprecedented resolution. Webb’s revolutionary technology will allow
scientists to explore every phase of cosmic history – from within our solar system to the most distant observable
galaxies in the early universe, and everything in between. Webb will reveal new and unexpected discoveries and
help humankind understand the origins of the universe, as well as our place in it.
The Webb observatory is so large it must fold up for launch and then unfold in space, like giant high-tech origami
Webb’s science objectives require the observatory to be very large – so large that, when expanded to full size, it can’t fit into the nose cone (i.e., fairing) of any available launch vehicle in its operational configuration.
One of Webb’s main components is the sunshield, a diamond-shaped structure roughly the area of a tennis court. It was carefully folded and packed to fit inside Webb’s launch vehicle, the Ariane 5 rocket. In space, the sunshield will expand, tension, and separate into its five distinct layers.
At over 21 feet (6.5 meters) in diameter and about 270 square feet (25 square meters) in area, Webb’s primary mirror is also too wide to fit into the Ariane 5 fairing in one piece, so it is segmented into 18 hexagonal pieces on a hinged structure so it can fold up for launch and unfold in space. It will be the largest mirror ever flown into space.
More details of Webb’s complex two-week unfolding process are outlined below.
Webb has a million-mile journey to reach its destination, where it can orbit the sun in line with Earth
This special orbit allows one side of Webb’s sunshield to always face the Sun, Earth, and Moon, blocking their
heat and light from reaching the telescope’s heat-sensitive optics. Webb’s month-long journey takes it to the second Lagrange (L2) point, one of five positions in space where the gravitational pull of the Sun and Earth bal-ances the centripetal force required for a spacecraft to move with them. This makes Lagrange points particularly useful for reducing the fuel required for a spacecraft to remain in position. The location also enables continuous communications with Webb through the Deep Space Network, an international array of giant antennas managed by NASA’s Jet Propulsion Laboratory (JPL).
Webb’s state-of-the-art scientific instruments are engineered to produce a treasure trove of awe-inspiring imagery and data
The instruments primarily have two functions:
1) imaging, or taking images of scientific targets; and 2) spectroscopy, or breaking down light into separate wavelengths – like raindrops create a rainbow – to determine the physical and chemical properties of various forms of cosmic matter. Learn more in the Instruments section.
Several new technologies were developed during the building of the Webb telescope, including innovative spinoffs that have already improved life here on Earth
In designing Webb, engineers had to imagine a telescope unlike any that has ever been built before. Technological advances, and even new inventions,
were necessary to make the mission feasible: Breakthrough lightweight deployable mirrors and advanced composite structures that align to millionths of millimeters and work at super-cold temperatures. Large, ultra-sensitive infrared light detectors.
A “microshutter” device with thousands of tiny windows, each the width of a human hair and programmable to be open or closed, to enable spectroscopic measurement of hundreds of individual objects simultaneously. A cryocooler that chills the mid-infrared detectors to the necessary temperature of only a handful of degrees above absolute zero.
Some Webb developments have had serendipitous spin-off benefits. One example assists surgeons performing LASIK eye surgery: Engineers developed a technique for precisely and rapidly measuring the mirrors to guide their grinding and polishing.
This technology has since been adapted to creating high-definition maps of patients’ eyes for improved surgical precision.
The James Webb Space Telescope’s very first science images are worth the wait
Webb begins gathering its first set of scientific observations after its commissioning process is complete, roughly six months after launch. The initial few weeks of commissioning includes Webb’s unfolding process, which occurs as Webb is on its month-long, million-mile journey to its operational orbit. The observatory then gradually cools down to its cryogenic operating temperatures before we can safely operate the science instruments (about 40 kelvins, or less than -380 degrees Fahrenheit), and the commissioning team aligns all of its mirrors and cali-brates its scientific instruments. In order for Webb’s primary mirror segments to act as a single optic, each of the 18 segments must be aligned to within a fraction of a wavelength of near-infrared light, i.e., mere nanometers, or about 1/10,000th the thickness of a human hair!