Technical, Cost Issues Persist For Webb Telescope

By Amy Svitak
Source: Aviation Week & Space Technology
July 22, 2013
Credit: NASA

For more than a decade NASA's most expensive science mission, the James Webb Space Telescope (JWST), has suffered cost growth and schedule delays owing to poor management and inadequate budgets. But until recently, technical progress on the enormous space observatory appeared sound.

Conceived in the late 1990s as a follow-on to the Hubble Space Telescope, JWST was projected to cost just $1 billion to build and launch an observatory so advanced it would revolutionize scientific understanding of star and planet formation and identify galaxies in the early universe.

By 2011, however, the program had seen almost a decade of cost overruns and schedule delays. Under pressure from lawmakers, NASA rebaselined the program with a revised cost estimate of $8.8 billion, a new launch date of October 2018, and a healthy amount of schedule margin to maintain both. At nearly nine times the original cost, and more than a decade behind schedule, JWST was finally on track.

Since then, the program has entered a critical phase; myriad technical concerns have emerged, including mass issues on the spacecraft, delayed delivery of two instruments and technical problems with key subsystems, one of which required the addition of a third round of lengthy cryo-vacuum testing to the Integrated Science Instrument Module (ISIM). Combined, these issues have cost 18 of 26 months of schedule reserve on the ISIM, the heart of the telescope that houses JWST's four instruments, designed to detect light from distant stars and galaxies.

One of the late instruments is the Near-infrared Spectrograph (NIRSpec), a 200-kg spectrometer designed to observe up to 100 celestial bodies simultaneously at various spectral resolutions being supplied by the European Space Agency (ESA) and built by Astrium GmbH of Ottobrun, Germany.

According to ESA, in July 2011 three cracks were found in the part that holds the optics components for NIRSpec. After a failure review board in January 2012, ESA had to reassemble the instrument using a flight spare optical bench.

During the rebuild and test, however, ESA encountered additional problems with NIRSpec, including failure of the NASA-supplied microshutter arrays to close. The project also suffered from slower-than-planned progress on the reintegration on the part of Astrium, according to the Government Accountability Office (GAO), which conducted an in-depth review of JWST in 2012.

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