NASA’s New Webb Space Telescope Checking All the Boxes As It Unfolds

NASA’s New Webb Space Telescope Checking All the Boxes As It Unfolds

Five days after launch, NASA’s new James Webb Space Telescope is checking off one box after another unfolding itself enroute to its destination a million miles from Earth. Many more steps are required, but so far so good.

The 6.5 meter diameter space observatory is too big to fit inside the Ariane 5 rocket that lofted it into space on Christmas Day. It is morphing from its cramped pre-launch configuration into its elegant final shape.

The James Webb Space Telescope in its folded congifuration at the Arianespace processing facility in Kourou, French Guiana prior to launch. Credit: NASA
Illustration of the James Webb Space Telescope fully deployed. Credit: NASA

Every step is critical, but some are more critical than others starting with deployment of the solar array that provides electrical power. By chance, a camera on the Ariane 5’s upper stage captured that moment less than a minute after the two separated.

JWST is a joint program among NASA, the European Space Agency, and the Canadian Space Agency.  Among ESA’s contributions was the launch, provided at no cost to NASA on Europe’s Ariane 5.  Arianespace’s rocket put the telescope on a path to the Sun-Earth Lagrange Point 2 (SEL-2) a million miles (1.5 million kilometers) from Earth.

The telescope has small engines of its own to make mid-course corrections to fine-tune the trajectory and then to keep the telescope orbiting that SEL-2 point in space. How long JWST can do its job thus is partially dependent on how much fuel is left after the mid-course corrections. Ariane 5 was so precise in getting JWST on its way that, in terms of fuel, JWST will be able to operate for more than 10 years.

JWST’s design life is five years and the life-cycle cost estimate of $9.7 billion is based on five years of operations. Scientists have long hoped that it actually might operate for twice that long, though the costs for extended operations are not part of NASA’s budget planning at this point. Many, perhaps most, NASA science missions last long beyond their design lives and NASA periodically conducts Senior Reviews to assess whether the science gathered is worth the continuing expense. Usually the answer is yes even though that may mean less money to begin new projects.

For JWST that question will be confronted years from now. At the moment, everyone is focused on getting it up and running in the first place.

Over the past five days, several crucial steps have proceeded as planned, including not only solar array deployment, but two mid-course corrections, lowering the two pallets for the sunshield, and lifting the tower on which the telescope’s primary mirror sits.

JWST will study the universe in infrared (heat) wavelengths, so its instruments must be very, very cold. One, the Mid-InfraRed Instrument (MIRI), must be kept at 7 degrees Kelvin (-447°F/-266°C). The others, NIRSpec, NIRCam, and FGS/NIRSS, operate at 40° K (-387°F/-233°C).

The sunshield protects the instruments from the heat and light of the Sun. Deployment is underway.

This next week will see sunshield tensioning and other deployment steps. The exact timing is flexible, but NASA said today it will provide live coverage on its website and the NASA App of sunshield tensioning no earlier than (NET) January 2, secondary mirror support structure deployment NET January 4, and final deployments NET January 7.

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