After two blogs,“Telescope: how it works“ and “Hubble Telescope: its purpose and progress“, to explain all about telescopes and the Hubble space telescope, we can finally reveal why so much information was needed. We would like to introduce you to the newest and most technologically advanced telescope to date, the James Webb Space Telescope.
What is the James Webb Space Telescope?
The creators of the telescope first named it “the next generation” because that is what it is: the next generation of telescopes that surpasses even the most recent additions to the Hubble Space telescope, and every other telescope created on the ground, in every way.
Is the James Webb Space Telescope similar to the Hubble Telescope?
There are some similarities on a grand scale, but those when you take a closer look they are not exactly alike.
- Like Hubble, this telescope will be orbiting in space, but instead of 250 miles from Earth, the James Webb Space Telescope will be orbiting a million miles away from Earth.
- Hubble had the same telescope design of mirrors to reflect light, but the mirrors on Hubble had been used in other places, whereas the mirrors on Webb were going to be placed far out in space where the temperature is extremely cold. The primary problem with that cold was the way it changed the materials the mirrors were made of. So scientists created new mirrors made of beryllium to make the smoothest possible texture. These mirrors are so smooth that they can reflect light particles as small as 20 nanometers in this extreme cold of -388 degrees Fahrenheit. Something that small is hard to imagine, so 20 nanometers can be compared in biological terms as about the size of a single protein or single strand of a virus.
- Both telescopes have mirrors that will allow them to see infrared light, but Hubble could just barely see light in that part of the light spectrum. The mirrors on James have just a tiny bit of gold sheeting to be able to detect the low and middle-levels of infrared wavelengths of light.
How is the James Webb Telescope completely different from Hubble?
This telescope will not have any protection from our atmosphere so it will have to have a sunshield. The problem with needing a sunshield is the weight and size needed for it and having to fit in a very small space within the rocket to launch it into space. The sunshield will also have to unfold, and the mirror has already taken most of the space. As a result they created a sunshield system of 5 membranes.
- Each membrane is 75 feet long, 5 feet wide, and 2 thousandths of an inch thick.
- The membranes were put together in 54 rectangular blocks with electronic welds.
- Between each of the 5 membranes is a tiny space. This spaces allows any heat that is not reflected by the membrane to be released out of the side.
- Any heat that penetrates the first membrane will have to face the second and so on giving a redundancy to make sure none of the 185 degrees Fahrenheit reach the telescope.
Even with the sunshield protection, the equipment and instruments mounted between the sunshield and the mirror will still give off heat. No telescope before has needed a cyrocooler, but the James Webb Telescope will have one that will use Helium to make sure all the delicate equipment and computers are cooled down from roughly 31 degrees Fahrenheit to nearly -450 degrees Fahrenheit. That’s around 50 degrees colder than the temperature of the mirror on the dark side of the telescope, but necessary to keep up with the 178 moving parts of machinery and instruments that will heat themselves up as they are used.
To be continued…
Apart from what it is made of, how big it is, and the technology it holds, it will be how scientists are going to get the telescope into orbit and what the telescope will do that will define this telescope for generations to come. Tune in next time to read all about it!