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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Arecibo Telescope | 3/6 | https://en.wikipedia.org/wiki/Arecibo_Telescope | reference | science, encyclopedia | 2026-05-05T13:15:38.928164+00:00 | kb-cron |
=== Upgrades === Since its construction, the telescope was upgraded several times, following the facility's oversight from the DoD to the National Science Foundation on October 1, 1969, and subsequent renaming of the AIO to the National Astronomy and Ionosphere Center (NAIC) in September 1971. Initially, when the maximum expected operating frequency was about 500 MHz, the surface consisted of half-inch galvanized wire mesh laid directly on the support cables. In 1973, a high-precision surface consisting of 38,000 individually adjustable aluminum panels replaced the old wire mesh, and the highest usable frequency rose to about 5000 MHz. A Gregorian reflector system was installed in 1997, incorporating secondary and tertiary reflectors to focus radio waves to one point. This allowed installing a suite of receivers, covering the full 1–10 GHz range, that could be easily moved to the focal point, giving Arecibo more flexibility. The additional instrumentation added 270 tonnes (300 short tons) to the platform, so six additional support cables were added, two for each tower. A metal mesh screen was also installed around the perimeter to block the ground's thermal radiation from reaching the feed antennas. As part of this upgrade, the power of the 2380 MHz transmitter was doubled to 1 MW by adding a second Klystron tube and improving the design. Finally, in 2013 with a grant of US$2.5 million, work for adding the ionospheric modification HF facility began, which was completed in 2015. The HF facility consisted, on the sender side, of six foldable 100 kW crossed dipoles inside the main dish, and a hanging 100m-wide subreflector mesh between the dish and the platform.
=== Funding reductions === The Astronomical Sciences and Atmospheric Sciences divisions of the NSF had financially supported Arecibo since its completion in the 1970s, with incremental support by NASA, for operating the planetary radar. In 2001 NASA announced a rampdown and elimination of its support of the planetary radar by 2005. In 2002, after several years of discussion, the US Congress passed a bill to double the NSF budget, and instructed the NSF to begin new projects. As a result, the NSF began committing to major projects. However, the funding increase never arrived and the NSF was left with the new commitments. In 2005 the Astronomical Sciences division commissioned a "Senior Review" of its facilities to deal with its increasingly constrained budget. The Senior Review report released in November 2006 "regretfully" recommended substantially decreased astronomy funding for the Arecibo Observatory, beginning with a cut to US$10.5 million in 2007 and continuing to decrease to US$4.0 million in 2011. The report further stated that if other sources of funding could not be found, closure of the Observatory was recommended. Academics and researchers responded by organizing to protect and advocate for the observatory. They established the Arecibo Science Advocacy Partnership (ASAP) in 2008, to advance the scientific excellence of Arecibo Observatory research and to publicize its accomplishments in astronomy, aeronomy and planetary radar as to seek additional funding support for the observatory. An additional US$3 million in bonds were issued by the government of Puerto Rico to fund the Observatory, which were used to modernize power generation and improve other aging infrastructure. Academics, media and influential politicians pressured the United States Congress on the importance of the work of the observatory. led to additional US$3.1 million in funding to support Arecibo in the American Recovery and Reinvestment Act of 2009. This was used for basic maintenance and for a second, much smaller, antenna to be used for very long baseline interferometry, new Klystron amplifiers for the planetary radar system and student training. Arecibo's budget from NSF continued to wane in the following years. Starting in FY2010, NASA restored its historical support by contributing $2.0 million per year for planetary science, particularly the study of near-Earth objects, at Arecibo. NASA implemented this funding through its Near Earth Object Observations program. NASA increased its support to $3.5 million per year in 2012. In 2011, NSF removed Cornell University, which had managed the National Astronomy and Ionosphere Center (NAIC) since the 1970s, as the operator and transferred these responsibilities to SRI International, along with two other managing partners, Universities Space Research Association and Universidad Metropolitana de Puerto Rico, with a number of other collaborators. NSF also decertified NAIC as a Federally Funded Research and Development Center (FFRDC), which the NSF said would give NAIC greater freedom to establish broader scientific partnerships and pursue funding opportunities for activities beyond the scope of those supported by NSF, but which would also remove the FFRDC's promise of stability intended to retain the very best technical staff. While the Observatory continued to operate under the reduced NSF budget and NASA funds, NSF signaled in 2015 and 2016 that it was looking towards potential decommissioning of the Observatory by initiating environmental impact statements on the effect of disassembling the unit. The NSF continued to indicate it would like to reduce funding to the Observatory in the short term. As in 2008, academics expressed their concern over the loss of scientific discoveries that could occur should the Observatory be shut down.
=== 2020 damage, decommissioning plans, and collapse ===