As early as 1923, space telescopes were proposed to peer deeper into the universe, without the obstruction of the Earth’s tenuous atmosphere. By the 1970s congress had funded the first of these great space telescopes, with the 2.4 meter primary mirror completed in 1981 for a Ritchey-Chreitien Cassegrain type telescope which finally launched in 1990 in the cargo bay of the Space Shuttle Discovery, carrying the name Hubble. A few servicing missions later, the Hubble Space Telescope has been gracing our computer screensavers with images of the cosmos for over 31 years.
Before it’s launch, however, NASA knew that the narrow visible spectrum that Hubble was designed to observe in was not the end-all goal of space telescopes. A series of additional orbiting laboratories able to capture light from all ends of the spectrum were developed, including the Chandra X-Ray Telescope, the Spitzer Space Telescope in the infrared, and the Kepler planet hunter telescope, but NASA engineers and astronomers dreamed of something bigger and better. In 1989, the concept was floated for a much, MUCH larger space telescope that could open like an umbrella, with multiple mirrors converging to create a 4-meter aperture telescope that could image across a much larger swath of the visible to near infrared spectrum. The next three decades of scientific advancements, engineering marvels, as well as numerous delays and drastic budget overruns have led up to this moment.
On December 25th the James Webb Space Telescope will launch aboard an Ariane 5 rocket from the European Space Agency spaceport in French Guyana, South America at 5:20 AM MST. Whereas Hubble orbits at about 330 miles above the Earth, making it a previously accessible target for repair and upgrade mission with the now retired fleet of Space Shuttles, The JWST will orbit the Sun at what is known as the L2 Lagrange point. This is a unique point in space where the gravitation forces of the Sun and Earth balance each other and create a stable point in space for an object to remain in relative equilibrium. There are 5 such Lagarange points created by the Sun/Earth gravity wells, with the benefit of the L2 point being that it will always be in a line with the Earth directly between it and the Sun, helping to block the Sun’s light – and astronomers like it dark! The JWST will take approximately a month to reach this point 1.5M km from earth, about 3 times further than the moon. During this time, the observatory will open its mirrors, solar panels, and a unique solar shield that will add additional protection from the light and heat of the sun, allowing for more detailed observations in the near and mid-infrared.
20 countries, more than 30 years, 9.7 billion dollars, and human capital that could never be accurately calculated, will all culminate in a Christmas gift to the world early this Saturday morning. God speed James Webb!
The Backyard Astronomer 