James Webb Space Telescope: Hopes & Expectations

December 25th may become known as the day the universe changed. On that day, NASA expects to launch the James Webb Space Telescope, the largest and most expensive instrument ever flown. One hundred times more powerful than the 31-year-old Hubble Telescope, Webb can see back in time all the way to the “let there be light” moment—that instant when a cold, dark universe ignited into stars.¹

The JWST was specifically designed to allow us to see the very first galaxies that formed after the Big Bang. Galaxies are born and then they evolve and change over time, and the way that galaxies change must rely critically on dark matter. James Webb is going to allow us to observe that process of galaxy evolution in more detail than ever before.²

It’s intended to answer two big questions in astrophysics: where did we come from, and are we alone? Our hope is that, just maybe, with the JWST, we’ll finally start to see the light!

There are many profound questions that the JWST will help us answer:

• What was the early universe really like?
• Can we actually see it? Can we actually watch as the stars “blink on”?
• What do the lives of stars really look like?
• How did galaxies evolve?
• What other worlds can we see?
• Do we see signs of life?

The answers have the potential to forever change our understanding of the universe and, in complex ways, our understanding of ourselves! Three Near IR instruments and one Mid IR Instrument on board the JWST will help answer these questions:

• NIRCam – for WFOV Deep Imaging (lead by the University of Arizona)
• NIRSpec – for Multi-Object Spectroscopy and Chronography (lead by ESA and Airbus Defense and Space)
• MIRI – for Mid IR Imaging and Spectroscopy and Chronography (lead by a European consortium, with the UK Astronomy Technology Centre and JPL)
• FGS/NIRSS – the Fine Guidance Sensor and Near IR Imaging Slitless Spectrometer and Chronography (lead by the Canadian Space Agency).
• Studying the transit and eclipses of the exo-planets, and the phase spectroscopy of their atmospheres, will be observed/detected by these state-of-the-art instruments.

The development of these instruments resulted in numerous new technologies and techniques, including (chronologically): New Near IR Detectors, Sunshield Materials, Primary Mirror Segment Assemblies, Mid IR Detectors, Cryo ASICs, Microshutter Arrays, Heat Switches, Large Precision Cryogenic Structures, Wavefront Sensing and Control,  Cryocoolers, High Speed Interferometry, Test Planning Software, and Mirror Cleaning.

The images below are taken from “JATIS Webinar: Webb is Ready to Launch!” webinar recording.

The following photographs show various stages of the JWST build process:

What happens after the launch?

• The JWST is unfolded in the following planned order:
  1. spacecraft appendages (solar arrays, high gain antenna)
  2. sunshield
  3. extend tower
  4. secondary mirror
  5. primary mirror
• For 30 days after launch, it takes a one-million-mile trip to L2 halo orbit.
• For six months, the JWST prepares for full-time science operation. This includes letting everything cool down, calibrating the mirrors and instruments, etc.
• The baseline five-year science mission starts after six months. Ten years of operation is the goal, and the JWST carries enough fuel to maintain its halo orbit for at least that long.