NASA Moves Forward With Webb Space Telescope Sunshield Tensioning

Engineers working on the James Webb Space Telescope fine-tuned its electrical power system to better cope with the actual space environment. It cooled down slightly warmer-than-expected motors before pressing ahead with the final deployment of the observatory’s integral sunshade.

Bill Ochs, the NASA project manager, said tightening up the sunshade’s five hair-thin layers, carefully pulling them taut with motor-driven cables running through multiple pulleys, likely would take three days to complete. By Monday night, three of the five layers had been pulled into shape, with the final two awaiting tightenings Tuesday.

The sunshade deployment has long been considered one of Webb’s most challenging hurdles, but he doesn’t expect any drama. The James Webb Space Telescope, the most expensive science probe ever built, was launched with great fanfare atop a European Space Agency-provided Ariane 5 rocket on Christmas Day, bound for an orbit around the sun a million miles from Earth.The telescope was designed to capture infrared light from the first stars and galaxies to form in the wake of the Big Bang; Webb is extraordinarily complex.

Other than the minor growing pains common to all new spacecraft, Ochs said the $10 billion observatories move through its initial activation almost precisely as planned.The sunshade is required to block out the heat of the sun, cooling Webb’s 21.3-foot-wide primary mirror and instruments to nearly 400 degrees below zero, cold enough to register faint infrared light from the first stars and galaxies to light up after the Big Bang.