Dec. 24th Update: In an update posted Friday on the health of its James Webb Space Telescope, NASA reported that engineers at Goddard Space Flight Center are "making good progress at identifying the root cause of the vibration anomaly." During two subsequent vibration tests, the large instrument was found to be in sound condition, and engineers expect to finalize their investigation and plans to move forward in early January. As about six months of "reserve" remain the the telescope's development timeline, its launch date of October 2018 has not yet been affected.

Original post: It's never a good thing when an anomaly is detected in your scientific instrument during pre-operational testing. When that instrument is the James Webb Space Telescope—which is expected to cost about $8.8 billion, cannot be fixed after launch, and is counted upon to provide insights about the earliest days of the Universe—it's cause for significant concern.

The anomaly occurred earlier this month, on December 3, during vibration testing at Goddard Space Flight Center in Maryland. As part of the run-up to a launch in late 2018, the telescope will be subjected to all manner of conditions, from extreme temperatures to a hard vacuum, to ensure that it will survive during its five- to 10-year mission in deep space. The telescope must also withstand its launch aboard an Ariane 5 rocket, and the vibration test mimicked the shaking and gravitational forces of launch. After the test began, accelerometers detected "anomalous readings," but so far the cause of the anomaly has yet to be determined.

"Further tests to identify the source of the anomaly are underway," the agency stated in an update. "The engineering team investigating the vibe anomaly has made numerous detailed visual inspections of the Webb telescope and has found no visible signs of damage. They are continuing their analysis of accelerometer data to better determine the source of the anomaly. They have conducted a low-level vibration of the hardware to measure its responses, and are comparing the results with data obtained prior to the anomaly. Engineers are currently running diagnostics to determine the cause and to assess any potential impacts."

The oldest and most distant objects in the Universe are moving away from Earth the fastest, so they have the largest red shift, best viewed in the infrared spectrum. The Webb telescope will specialize in the infrared and, therefore, should capture images of the Universe's first stars and galaxies, which formed only 200 million years after the Big Bang.

This telescope is vitally important to the astronomy community because of its unique capabilities for a space-based telescope and also because Webb has cost so much it has had a deleterious effect on other parts of NASA's science budget. It is too big to fail.