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Web Telescope Orbit, Pic Courtesy of NASA

 

So there is some good news for the Space Cadet corps this week. The James Webb Space Telescope (JWST) has been fully funded in the Senate. This is big news because the House had fully defunded the project.

A lot of the press about JWST says that it is the replacement for the Hubble Space Telescope, but that really does not tell the whole story. You see, JWST is different in just about every particular from the Hubble.

The JWST is designed to “see” in infrared, as well as visible light. This is important because it will be able to further back into time (by way of distance) and give us new data about the early universe that can not be achieved with the Hubble.

It also features a huge and adjustable main mirror, that will be 21 feet in diameter when it deploys. That that the mirror can launch in a folded state and then deploy to the full size is a major difference between the Hubble and JWST. Hubble’s mirror was designed to sit inside the telescope by the new observatory will have it open to space.

With this design and infrared capability there are unique requirements for this telescope. It must be shielded from the heat radiated by the Sun and Earth and must be in a position that will be dark most of the time. The only one place where these conditions exist are at the L-2 point on the far side of the Moon. That is what the graphic above is of.

L-2 stands for Lagrange point 2. This is named after the mathematician who calculated places of orbital stability between orbiting objects. The most commonly known Lagrange points at L-4 and L-5 which are 60 degrees ahead and behind the orbit of the Earth. L-2 on the other hand is a lot closer, it is on the other side of the Moon.

If this project goes ahead, we will park the JWST about 1.5 million kilometers, or about 932,000 miles away. In this spot it will be able to maintain its position with very little use of its rocket fuel. And it will be protected (mostly) from the light and heat of the Earth and the Sun.

It is a very good thing that this project is going forward. Beyond the science which this telescope will be able to perform the experience of placing and operating an observatory this far from the Earth will be a major step forward in our deep space capability. The knowledge gained will help in many forms of manned exploration.

It remains to be seen if the money will stay in the budget for this project. Like everything this new and complex, it has run over budget by quite a bit. Then again so did the Hubble. Can any of you imagine what the world would be like without the pictures we have been treated to over the life of that telescope.

So tonight we can be happy that the JWST is still in progress for its 2018 launch. If there is even a little foresight in Congress it will make that launch date and we will take another huge step forward to learning about and understanding our Universe.

What is on your minds tonight Firedogs? The floor is yours.

Bill Egnor

Bill Egnor

I am a life long Democrat from a political family. Work wise I am a Six Sigma Black Belt (process improvement project manager) and Freelance reporter for Govtrak.org

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