90-milliardersprosjekt utsatt - Curt Lewis

Webb Telescope Faces 5-8 Month Launch Setback

HOUSTON-The planned launch of NASA's $8.8 billion James Webb Space Telescope is slipping from October 2018 to between March and June of 2019 to accommodate further hardware integration and pre-mission preparations, the space agency announced Sept. 28.

JWST's five- to 10-year mission to seek out the earliest, most distant galaxies and search the atmospheres of extrasolar planets for signs of biomarkers with the partnering European and Canadian space agencies will kick off with an Ariane 5 launch from Kourou, French Guiana.

NASA reassessed the launch schedule to allow for longer-than-expected integration and testing of the spacecraft bus and tennis court-sized Sun shield at Northrop Grumman Aerospace Systems, of Redondo Beach, California, the prime contractor.

"The change in launch timing is not indicative of hardware or technical performance concerns,'' said Thomas Zurbuchen, the director of NASA's science mission directorate, as part of the announcement. Rather, the integration of the various spacecraft elements is taking longer than expected."

The observatory's existing budget remains adequate to accommodate the change, and planned science operations will not be jeopardized, according to NASA's update.

JWST is no stranger to setbacks. The observatory was first conceived in 1996 as a follow-on to the now 27-year-old Hubble Space Telescope. Early cost estimates ranged from $1 billion to $3.5 billion, with launch between 2007 and 2011, according to a previous U.S. Government Accountability Office audit. The program achieved new stability after reforms in 2011.

Meanwhile, the telescope hardware itself is now in a slow warm-up phase as it emerges from a challenging thermal vacuum chamber test at NASA's Johnson Space Center here. The testing was configured to assess how the infrared observatory will function in temperatures of about -400F, or 33K, at its final destination, the L-2 Sun/Earth LaGrange point about 1 million mi. from Earth.

The massive circular door to the nearly nine-story Apollo-era thermal vacuum chamber that surrounds the James Webb's 18-segment mirror and integrated science module was closed on July 11. The gradual warm-up to 68F, or 293K, that got underway on Sept. 27 will permit the low-temperature vacuum testing to reach its goal of 93 to 100 days duration by mid-October, when the door is to be unsealed, according to Rob Gutro, a spokesman for NASA's Goddard Space Flight Center in Greenbelt, Maryland, which manages JWST development.

A day later, chamber temperatures simulating those at the JWST's L-2 final destination had warmed to -373F, or 48.2K. Outside of the test facility housing Johnson's Chamber A and the telescope, skies were sunny as temperatures climbed to near 90F, high enough to continue erasing memories of Hurricane Harvey that drenched Houston and JSC with more than 40 in. of rain between late August and early September.

Though Johnson was forced to close for more than a week to cope with Harvey's high water and some roof leaks, JWST testing continued without interruption and is supplying the desired prelaunch data, Gutro said.

The telescope hardware and components reached Houston from Goddard by C-5 air transport on May 4, or about two months later than planned. That setback was linked to trouble with vibration and acoustic testing simulating the launch environment on the 21-ft.-wide mirror and science instrument package.

When it departs Houston at the completion of the thermal vacuum test, the telescope's comex primary mirror and science module are to be flown to Northrop Grumman facilities in Redondo Beach, California, where they are to be integrated with the spacecraft bus and Sun shield for further prelaunch testing.

The latest launch delay will provide additional environmental testing of the fully assembled observatory to ensure a thorough evaluation, including lessons learned. Evaluations to date indicate the hardware is meeting its required performance levels, according to the agency's Sept. 28 update.

Once final assembly and testing are complete at Northrop Grumman, JWST is to be transported by barge to the European Space Agency's launch complex in French Guiana.