Arecibo’s To-be-determined Future

The National Science Foundation (NSF) made a report to Congress final week that particulars the harm to the 1,000-foot radio telescope following the collapse of the 900-ton instrument platform that was suspended above the aluminum dish. The report revealed particulars in regards to the occasions main as much as the collapse, in addition to a stay up for what’s subsequent for the Arecibo Observatory.

Even as a few of Arecibo’s operations proceed, the NSF is contemplating its choices for repairing different capabilities. Meanwhile, a gaggle of scientists and engineers is proposing not simply repairs however a full-on substitute that guarantees a dramatic enhance in energy and sensitivity.

The Collapse

Arecibo dish damage
This picture exhibits the harm wrought by the primary cable failure on August sixth.

The NSF report outlines an in depth timeline of occasions:

  • August 10, 2020, 3 a.m. ET
    An auxiliary cable from Tower 4 pulls free from its socket. The cable falls onto the dish beneath, damaging some 250 of 40,000 aluminum tiles that make up the reflective dish.
  • August and September
    Engineers mannequin assist buildings and decide a security plan to be able to entry the failed socket on Tower 4. They additionally develop a stabilization plan for repairs.
  • End of September
    NSF authorizes an order for substitute cables, because of arrive in December. Stabilization efforts previous to substitute are set to start November ninth.
  • Early October
    Engineers take away the failed socket and ship it to the NASA Kennedy Space Center for evaluation.
  • November 6, 2020, 8:15 p.m.
    A primary cable from the identical tower, Tower 4, breaks.
  • November 19, 2020
    NSF publicizes that the 305-meter radio telescope must be dismantled, as repairs can’t be made with out jeopardizing security.
  • November 24, 2020
    NSF confirms that extra wires throughout the thick cables are persevering with to snap.
  • December 1, 2020, 7:00 a.m.
    The remaining cables from Tower 4 snap and the suspended platform crashes down on the dish beneath, inflicting in depth harm.

The collapse additionally ripped off the highest 18 meters (60 ft) of Towers 4 and 12, and the highest 37 meters of the taller Tower 8. Outside of the dish, towers, and different assist buildings, harm was surprisingly restricted, principally to constructing roofs. A variety of the observatory’s services, together with LIDAR and optics to look at the ambiance as effectively a 12-meter radio telescope, are nonetheless operational.

NSF states that investigation into the collapse is ongoing. Engineers proceed to analyze the failed socket concerned within the auxiliary cable’s loss in addition to the primary cables, which NSF says have been “weaker than expected.” The primary and auxiliary cables date to the Sixties and the Nineties, respectively. NSF expects to have ultimate stories on these investigations by December 2021.

The Repairs

Cleanup has begun, but it surely’s a protracted course of that can proceed into 2022, costing some $30–50 million. Engineers have mapped the particles from the collapse and employees have made good progress, as could be seen within the overhead picture beneath. Cleanup isn’t solely about eradicating equipment; there are environmental results, too. For instance, employees are additionally excavating soil contaminated with hydraulic oil launched throughout the collapse.

Anything that’s nonetheless scientifically usable is staying put, although, as NSF remains to be deciding find out how to proceed with repairs. The group is convening a gathering of scientists and engineers within the April timeframe to contemplate subsequent steps.

One possibility on the desk is to rebuild the 305-meter reflecting dish and proceed research of Earth’s ambiance utilizing devices just like the High Frequency ionospheric heaters and incoherent scatter radar.

But to conduct astronomy or planetary research, the dish must get replaced. Some, led by Arecibo senior scientist Anish Roshi, are proposing a substitute that will be vastly completely different — and extra highly effective — than what’s there now.

A Replacement

Here’s the concept as outlined in a white paper circulated by Roshi and his colleagues: The Next Generation Arecibo Telescope would pack a whole bunch, perhaps much more than 1,000 smaller radio dishes into the identical space now occupied by the one 305-meter dish. Those smaller antennas would mix forces to behave like a single bigger telescope (no suspended instrument platform required).

Ideally, these dishes could be on a single, tiltable platform to entry extra of the sky from the Arecibo web site; it’s attainable a number of platforms may do the identical.

Next Generation Arecibo Telescope possible designs
Two attainable designs of the Next Generation Arecibo Telescope are proven right here: 1,112 parabolic reflectors which might be every 9 meters in diameter (left) or 400 dishes 15 meters in diameter (proper). In each instances proven right here, the arrays are positioned on a single, tiltable platform.
Roshi et al. / arXiv

The revamped telescope would have twice the sky protection of the legacy dish, 500 instances the sphere of view in particular person pictures, at the least double the sensitivity, and 5 instances the radar energy.

Those new capabilities open up numerous new science. For instance, the elevated sky protection would put the galactic middle in view, permitting astronomers to seek for pulsars orbiting the supermassive black hole lurking there and enabling unprecedented assessments of normal relativity.

A tough estimate places the price of such a facility at $454 million, lower than the price of producing and advertising Avengers: Endgame. A more true estimate will come as soon as the telescope’s design is hammered out.

“The Next Generation Arecibo Telescope will not start from scratch,” the staff states on their website. “It will take advantage of the existing infrastructure, decades of experience, and the support of the local people and government.”

Pluton space radar
The Pluton radar system in Crimea consists of eight reflectors, every 16 meters in diameter. It serves as a working instance of a compact dish array mounted on a plane.
Rumlin / Wikimedia Commons / CC BY-SA 3.0

To Be Decided

The plan is thrilling to make sure, however the ultimate resolution is probably going a protracted way off.

“NSF has a very well-defined process for funding and constructing large scale infrastructure, including telescopes,” stated Ralph Gaume, director of NSF’s astronomy division. “It’s a multi-year process that involves congressional appropriations, and the assessment and needs of the scientific community. So it’s very early for us to comment on the replacement.” While Gaume issued that assertion at a December press convention, it’s no much less true now.

And it’s price holding in thoughts that along with any Arecibo repairs, NSF additionally must fund the under-construction Vera C. Rubin Observatory, the just-commissioned Daniel Ok. Inouye Solar Telescope, the ALMA radio array in Chile, the LIGO gravitational-wave detectors, and a number of other different services. All these huge, costly devices compete for a similar out there funds.

A separate Congressional appropriation is theoretically attainable — that’s what helped rebuild the 100-meter Green Bank Telescope following its sudden collapse in 1988. The political realities are a bit completely different in Puerto Rico than in West Virginia, however quite a few representatives have expressed support for rebuilding Arecibo.

The astronomy group’s decadal survey, which outlines funding priorities for the following 10 years (or extra) and is due out within the subsequent couple months, may additionally play a job in deciding Arecibo’s destiny.

In the meantime, NSF is contemplating all proposals — the ground is open.

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