Friday, April 24, 2015

Missed It By That Much

The welding tool that was to build the Space Launch System. Image source: NASA via Space News.

Space News reports that assembly of the Space Launch System faces an unknown delay after it was discovered that a welding tool at NASA's Michoud facility is out of alignment.

Dan Leone reports:

The problem was due to a “miscommunication” between two ESAB suncontractors, Todd May, NASA’s SLS program manager, said here after an April 15 panel discussion at the National Space Symposium.

“The requirement, which was to be horizontal within one eighth of an inch [0.3175 centimeters] measured 170 feet up was not passed to one subcontractor, and instead that subcontractor used the standard tolerance requirements for plate flatness to horizontal within 0.06 inches at the base of the tower,” May wrote in a subsequent email to SpaceNews April 20. “This corresponded to a roughly 2.5-inch [6.35 centimeter] misalignment at the top, compared with the intent to have to towers horizontal to within one eighth of an inch [0.3175 centimeters].”

In other words, the [Vertical Assembly Center]’s baseplate, which secures the tool to Michoud’s concrete floor, was cocked too far to one side. The angle was very slight — the highest part of the baseplate was less than half a centimeter above its lowest part — but it was enough to put the whole tool out of alignment, May said.

While the baseplate’s alignment can be corrected easily enough, the plate sits at the very bottom of the VAC and cannot be accessed without disassembling substantial parts of the machine, said May.

Leone reported that “the exact effect on SLS’s development, both in terms of cost and possible delays, has yet to be calculated.” The facility was supposed to have been completed in March.

As I wrote in March, various statements and reports have implied that the Orion crew capsule necessary for the first SLS test flight has already slipped into 2019. NASA officials for now stick to their end-of-2018 launch date, but today's Space News reports adds more credence to the notion that we won't see SLS launch from Pad 39B until at least 2019.

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