What We Know About the New Space Telescope

Andrew Bronshteyn/Webmaster

Scheduled for Oct. of 2018, NASA will be hauling 7.15 tons of pure science 1 million miles away from Earth. With a primary mirror 2.75 times larger than the Hubble Telescope’s, the James Webb Space Telescope (JWST) will be the largest and most precise telescope in space. Running $3 billion over budget and many years past schedule, the project was nearly cancelled in 2011. NASA plans to launch the JWST on an Ariane 5 launch vehicle in just two more years.

Once in space, the solar panels and the high-gain antenna will deploy. After a week in space, it will unfold the tennis-court-sized sun shield – to protect it from the light and heat from the sun and Earth – and deploy the telescope and all of the focusing mirrors. Then, the next six months are a series of instrument tests, optimizations, and adjustments. What the telescope will look at first is currently to-be-determined by NASA and its affiliates.

The telescope will be located at the 2nd Sun-Earth Lagrange point, one million miles away from us. It will be effectively using the Earth as a shield; the point where it orbits is always between the Earth and the sun. However, it will still need its sun shield to protect itself and the sensitive technology inside.

Unfortunately, this also means that it is beyond the reach of repairs, meaning that the engineers building it are being very careful and double-checking everything. In fact, each of the eighteen mirrors is individually checked and double-checked, and they will be checked as a whole when they are all assembled. A lesson learned from the expensive Hubble mishap, caused by a simple error in imperial-metric conversion.

The mirrors, despite being incredibly large (21 feet in diameter when deployed), are quite light thanks to being made out of beryllium – the lightest alkaline metal on the periodic table. The mirrors are coated in a thin (100 nanometer) layer of gold to aid in the reflection of red and infrared light. Despite covering such a massive area, the amount of gold used has a similar mass to that of a golf ball. The point of using gold is its highly reflective nature and ability to reflect red and infrared light, which are the primary light frequencies that its sensors will be using.

Image courtesy: Northrup Grumman  An artist’s rendition of the James Webb Space Telescope, which will look into deep space to find information about the early formation of galaxies. THE JWST is projected to be launched in 2018, on an Ariane V launch vehicle.

But what are its goals? NASA gave the mission four distinct goals that they want the JWST to accomplish before the end of its lifespan:

“1)   Search for the first galaxies or luminous objects that formed after the Big Bang.

2)   Determine how galaxies evolved from their formation until the present.

3)   Observe the formation of stars from the first stages to the formation of planetary systems.

4)   Measure the physical and chemical properties of planetary systems and investigate the potential for life in those systems.” – JWST.NASA.Gov

Speaking of its lifespan, the engineers are building it to last no less than 5.5 years, with the goal that it lasts for 10. With its incredibly advanced sensors, it will look deeper and more clearly than the Hubble can. The sensors are special, not only for their accuracy and precision, but also because they will operate only 50 Kelvin above absolute zero. That is -370 degrees Fahrenheit! Whereas the outer layer of the sun shield will be at a cozy 185 degrees Fahrenheit: a 555-degree difference.

Onboard the spacecraft the advanced scientific instruments include: the Near Infrared Camera (NIRCam) made by the University of Arizona and Lockheed Martin, the Near-Infrared Spectrograph (NIRSpec) made by the European Space Agency, the Mid-Infrared Instrument (MIRI) made by the MIRI Consortium and the Fine Guidance Sensor/Near InfraRed Imager and Slitless Spectrograph (FGS-NIRISS) made by the Canadian Space Agency.

The James Webb Space Telescope is taking a long, arduous journey to completion and launch, one that is not yet finished. But when the telescope finally reaches its intended location, the knowledge that it beams back to Earth will make all the hard work worthwhile. No doubt countless a thesis will be based on the data that it sends back.