How a Single Plate Failed and Destroyed the 300-Foot Green Bank Telescope

On November 15, 1988, the 300-foot radio telescopeRadio telescopeA specialized antenna and receiver system used to detect radio waves from space. Open in glossary in Green Bank, West Virginia, collapsed suddenly at 9:46 p.m. The failure occurred on a clear night with calm weather. When observatory personnel arrived the following morning, the instrument was a massive pile of twisted metal debris.

The Cause of the Collapse

Investigators discovered that the structure collapsed under its own weight after a critical part known as a gusset plateGusset plateA thick piece of steel used to join structural beams together. Open in glossary gave way. This steel connector was one of four plates holding the major metal beams together. The analysis showed that unforeseeable stress factors cracked the plate. The component was simply never built to survive the 26 years the facility had remained in active service.

The telescope had originally been built in just two years. That rapid construction schedule created issues over time. By 1970, weight, snow, and maintenance traffic had warped the dish surface. That forced workers to replace it with a finer aluminum mesh and install an expanded traveling feed at the prime focus.

Scientific Impact and Replacement

Before its sudden loss, the facility was the largest radio observatory in the world. It delivered major scientific results throughout its decades of operation, including contributions to dark matterDark matterAn invisible form of matter that scientists believe provides extra gravity to hold galaxies together. Open in glossary research and the discovery that pulsars originate from supernovaSupernovaA powerful and luminous explosion of a massive star at the end of its life. Open in glossary explosions.

• It mapped celestial radio sources via the Green Bank 6cm Survey.
• That catalog covers nearly every northern hemisphere radio object investigated by other observatories.
• The collapse led directly to the development of a successor facility.

Three years after the disaster, workers broke ground on a replacement. The new Green Bank Telescope was designed to be even larger and more sensitive than its predecessor, officially beginning scientific observations in 2001.