The James Web Space Telescope project has been plagued with problems, funding issues, and a long list of delays. The latest delay came today and pushed the launch date off to Christmas eve.
Hopefully, in late December, its historic five to ten-year mission of scientific discovery will finally begin. The James Webb Space Telescope – the most powerful, most complex, and most expensive space telescope in human history – will be folded up, tucked inside a massive rocket, then blasted into space on a million-mile journey.
The James Webb Space Telescope has been a 25-year effort. It should provide surprising and unexpected discoveries. Scientists believe it will shed light on several science mysteries, including providing us with clues about one of the biggest mysteries in the universe – dark matter.
Despite its cost of $10 billion and delays, the James Webb observatory has been reported as ready for launch. At a weight of 7-tons, it is the T-Rex of space telescopes. A European Space Agency Ariane 5 rocket will carry the three-story space observatory into space after a launch from Kourou, French Guiana, near the equator.
Destination in space – Lagrange Point 2
The telescope’s destination is a mathematical point in space beyond the moon called Lagrange point 2 (LP2). LP2 lines up with the sun, Earth, and moon, positioning the telescope to remain in the same approximate orbit for 23 days before any course corrections are needed. The telescope won’t remain stationary at L2. Imagine the Webb telescope is a wheel rotating on an axle that consists of a straight line between the moon, the Earth, and the sun.
Parking the James Webb Space Telescope at LP2 serves several purposes:
- Instead of requiring continuous course corrections, locating Webb at LP2 saves fuel because it only requires a minor course correction every 23 days.
- LP2 uses the Earth and the moon to shield the telescope from sunlight and heat.
Once Webb settles in at LP2, it will be almost a million miles from Earth. It will be so far away that it will be impossible to perform traditional maintenance if anything goes wrong. If that happens, our investment will turn into $10 billion worth of space junk.
During its month-long trip from Earth to Lagrange point 2, the Webb will begin the unfolding process, starting first with the sunshield.
To protect its extremely sensitive mirrors and sensors, the Webb observatory must be protected from all sources of heat. The five mylar-like layers of sunshield is a very efficient insulator. Once unfolded, the sunshield will be about the size of a tennis court. It is definitely a fire and ice situation because the shield produces a temperature differential of more than 600 degrees Fahrenheit.
On the solar side of the shield, the temperature is oven-hot. Still, on Webb’s instrument side of the shield, protected by five layers of thin material, the temperature will remain a few degrees above absolute zero.
Space telescopes and large ground telescopes use mirrors to gather dim ultraviolet and visible starlight. A larger mirror can collect more photons of light, and better imaging is possible.
To fit Webb’s mirror into the rocket, engineers reduced it to 18 separate small gold-coated beryllium mirrors hinged together. Like the sunshield, once in space, the cluster of hexagonal mirrors will unfold to form a large 21-foot diameter mirror with a light-gathering surface area of 273 square feet. The process must be done flawlessly, and once unfolded, the pieces must fit together with incredible precision.
In addition to its shield and mirror, the Webb will be equipped with four incredibly sensitive instruments:
- Near-Infrared Camera
- Near-Infrared Spectrograph
- Mid-Infrared Instrument
- Near-Infrared Imager and Slitless Spectrograph with the Fine Guidance Sensor
It will take the Webb about a month to reach LP2. Once there, it will require another 5-6 months to orient and optimize its components and instruments. When that is complete, and assuming it is flawless, the Webb will begin its mission.
Differences between Hubble and the James Webb Space Telescope
Since its launch in 1990, the Hubble Space Telescope has made a number of significant contributions to our knowledge of the universe. It has helped determine the age of the universe and its rate of expansion. It also revealed that almost every galaxy has a massive black hole at its center.
NASA doesn’t like to label the James Webb Space Telescope as a Hubble replacement. However, there are significant differences.
Hubble sees the light from galaxies and stars in visible and ultraviolet wavelengths.
The Webb observatory is designed to image infrared wavelengths rather than visible light. Because the universe is expanding, visible light’s wavelength lengthens as it travels billions of light-years across an expanding universe, changing from visible light into very weak infrared light. This transformation of light is the reason early galaxies can only be seen with an infrared telescope such as the Webb observatory.
The above photographs illustrate the difference between an image using visible light (left) and an image created with infrared (right). Because infrared can cut through the haze and detect older galaxies and stars, more details are visible in the infrared image. In this case, Hubble took both images. However, the James Webb Space Telescope is 100X more powerful than the Hubble, and it has a much higher resolution. Comparing these images to ones taken by the Webb would reveal a very dramatic difference.
Seeing what we’ve never seen before
On the size scale of the universe, there is a direct correlation between distance and time. For instance, Canis Major Dwarf Galaxy is our closest galactic neighbor. It is 236,000,000,000,000,000 miles away and its light takes 25,000 years to reach us, so its distance is 25,000 light-years.
We can see this galaxy with regular telescopes because it is a relatively young and its light remains in the visible and ultraviolet spectrum. When we look at Canis Major through a telescope, the instrument acts like a time machine that allows us to see the galaxy as it existed 25,000 years ago. If something happened to the galaxy in real-time as you were looking at it, you would have to wait 25,000 years to find out what happened.
Webb’s infrared capabilities will advance our scientific knowledge about conditions and stellar objects that existed in the early universe. It will enable us to see the early galaxies and stars that formed about a billion years after the Big Bang.
The James Webb Space Telescope is our new time machine. It can travel back in time even further than the Hubble. With it, we can use infrared light to see early stars and galaxies over 13 billion years ago.
The Webb space observatory will be conducting many studies. It will collect details about the black hole in our galaxy, determine the chemical make-up of protoplanets in the process of being formed. It will also examine exoplanets that orbit fully-formed around distant stars to determine if chemical biosignatures are present for chemicals needed to create or sustain life.
What if the mission fails?
Top Webb scientists have expressed near 100% confidence in the mission’s ultimate success. However, it can’t be ignored that the James Webb Space Telescope is one of the most ambitious and most complex science projects ever undertaken. Its success depends on perfectly timed execution of hundreds of operations that must be executed precisely during the unfolding process.
What happens if it fails to work after all our efforts and expense?
The human spirit and our thirst for knowledge will persevere. If nothing else, we will have gained experience that can shorten the time to develop, execute, and deploy another infrared space telescope. Maybe we can do it in ten years or perhaps 15 instead of 25 years.
But one thing is for sure. This mission is too important. If it fails, we must keep trying until we get it right.
Note: Moor Insights & Strategy writers and editors may have contributed to this article.