The James Webb Space Telescope: Final Preparations Before Launch
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Chapter 1: Unfurling the Golden Mirror
The remarkable mirror of the James Webb Space Telescope (JWST) has been unfurled for the last time on Earth as it prepares for its monumental journey into space.
This impressive golden mirror, consisting of 18 hexagonal segments, is designed to be compact for launch, fitting snugly within the rocket that will carry it into orbit. As engineers gear up for this historic mission, they conducted the final unfurling of the 6.5-meter (21-foot) primary mirror, using support wires to simulate the conditions of microgravity that it will encounter in space.
Lee Feinberg, the optical telescope element manager at NASA’s Goddard Space Flight Center, remarked, “The primary mirror is a technological marvel. When fully deployed, the lightweight mirrors, coatings, actuators, mechanisms, electronics, and thermal blankets create a single, precise mirror that is truly extraordinary.”
Join us on Astronomy News with The Cosmic Companion on May 18 for a discussion with Scott Lambros, NASA’s Instrument Systems Manager for JWST.
Section 1.1: Testing Commands and Controls
During this crucial test, the JWST's onboard computers received commands from its control room in Redondo Beach, California. These commands, which are identical to those that will be used in space, directed the telescope's mirror to deploy and secure itself in place.
“When Webb is in space, commands will be sent from STScI to one of three Deep Space Network facilities: Goldstone, California; Madrid, Spain; or Canberra, Australia. Signals will then reach the observatory nearly one million miles away. Furthermore, NASA’s Tracking and Data Relay Satellite network — including locations in New Mexico, Kenya, and Germany — will maintain consistent communication with Webb,” explained NASA officials.
The golden mirror segments, equipped with all necessary insulation and shielding for space, successfully expanded to their full size. After this test, the mirror was folded back and secured, ready for its launch.
Subsection 1.1.1: The Importance of Diameter
One key factor for a telescope’s effectiveness is its diameter, which dictates its light-gathering capabilities. With a primary mirror that is over three times wider than Hubble's, Webb is expected to capture approximately nine times more light than its predecessor, which has been in operation for 30 years.
However, this sizable mirror also presents challenges for launch. The innovative solution involves folding the mirror, akin to origami, allowing it to fit within the 5-meter (16.5-foot) fairing of the Ariane-5 rocket.
“We shouldn’t persuade people that we can simply conjure up the sun and the moon: at the most, we can deliver a telescope,” — Jean-Claude Juncker.
Opening the mirror entails the use of 132 independent actuators and motors. After the telescope reaches its operational position, additional actuators will make fine adjustments to the mirror segments, ensuring they align precisely for observations.
Chapter 2: The Journey Ahead
Liftoff for the JWST is currently slated for Halloween, although potential delays may occur due to unforeseen challenges. Unlike the Hubble Space Telescope, which operates in low Earth orbit, the James Webb Space Telescope will perform its observations one million miles from our planet, making it inaccessible for servicing missions. Consequently, NASA must ensure that this groundbreaking telescope functions flawlessly prior to its launch.
Upcoming tests for Webb include extending and retracting its deployable tower, which is a pipe-like structure made of graphite-epoxy composite designed to insulate the mirror from the heat of the sunlit side of the craft. Additionally, two radiator assemblies that help cool the telescope will undergo similar tests.
Once successfully positioned in its orbital home, the James Webb Space Telescope will tackle questions about our solar system, explore exoplanets around distant stars, and delve into the mysteries of the early Universe.
James Maynard, the founder and publisher of The Cosmic Companion, resides in Tucson with his wife Nicole and their cat, Max.
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