News Items NSF Planning to Decommission Arecibo Observatory’s 305-meter Telescope

NEWS ITEM

NSF begins planning for decommissioning of Arecibo Observatory’s 305-meter telescope

The National Science Foundation (NSF) has provided a report to Congress, as required by the report language accompanying the Consolidated Appropriations Act, 2021, describing “the causes and extent of the damage, the plan to remove debris in a safe and environmentally sound way, the preservation of the associated AO facilities and surrounding areas, and the process for determining whether to establish comparable technology at the site, along with any associated cost estimates.” The investigation of the collapse and exploration of future opportunities for Arecibo is ongoing. The report is available at https://www.nsf.gov/news/reports/AreciboReportFINALProtected_508.pdf. A series of catastrophic events occurred at Arecibo in November 2020 that culminated in breakages to the supporting cables and the collapse of the 900-ton science platform suspended over the telescope's 305-meter aluminum dish. The famous radio telescope had survived hurricanes and earthquakes, but had become unstable as supporting cables and wires failed and snapped. The platform and the dome crashed into the reflective dish in the early morning of December 1. Arecibo was the largest fixed aperture telescope in the world. In 2016, China’s FAST telescope came online. Debates continued over which telescope had better sensitivity and performance under the definitions of “fixed aperture” and regarding other distinctions and capabilities. But for 57 years, Arecibo contributed to many important discoveries across many disciplines, including radar and radio astronomy, atmospheric science, and planetary science. Just a few highlights include: • determining Mercury’s rotation of 59 days • preparing lunar radar maps used to determine a landing site for the Apollo 11 mission • mapping landing sites for the Mars Viking program • sending the “Arecibo Message” radio signals into space for alien detection • discovering the first binary pulsar that verified predictions from Albert Einstein’s theory of general relativity • generating the first radar maps of Venus’ surface • discovering the first exoplanets outside our Solar

System, rotating around a pulsar • detecting ice on the polar regions of Mercury • participating in planetary defense by tracking asteroids

Arecibo Observatory prior to the collapse.

Arecibo Observatory’s 900-ton equipment platform.

Approximately 350 scientists used Arecibo annually along with 100 staff; and, 100,000 visitors came to Arecibo each year. Arecibo served as an important scientific and educational establishment for Puerto Rico, and even served as a FEMA emergency operations location following Hurricane Maria in 2017. Future plans for Arecibo remain in flux. Various groups have rallied to plan for rebuilding the telescope. Other options include using the site for further scientific research by utilizing other equipment and capabilities at the facility. The price tags for the different options vary, but are significant, ranging from $200-$400 million. Arecibo supporters published a white paper in February 2021 outlining key scientific objectives and novel capabilities that a new facility could offer. The white paper is available at http://www.naic.edu/ngat/NGAT-WhitePaper_ v2.0_03042021.pdf and an executive summary is available at http://www.naic.edu/ngat/NGAT-Summary_ v2.0_03042021.pdf.

SOURCES

The March 3, 2021 NSF News Release 20-010 is available at https://www.nsf.gov/news/news_summ. jsp?cntn_id=301674. Other sources reviewed include Miami Herald (December 12, 2020), Scientific American (December 11, 2020), Nature (December 18, 2020), Physicsworld (January 4, 2021), and Science (January 14, 2021) as well as the Arecibo Observatory website at https://www.naic.edu/ao/ landing.

Arecibo Observatory after the collapse.