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On Losing Arecibo

I always wanted to get to Arecibo, the magnificent 305-meter telescope that has for so long been a locus for radio astronomy research, but I was never able to make it to Puerto Rico. Now I’ve run out of time. The National Science Foundation doesn’t make these decisions lightly but multiple engineering companies have delivered assessments that point to catastrophic failure of the telescope structure as a real possibility. Too dangerous to repair, and faced with stability issues even if it could be repaired, the Arecibo Observatory will be decommissioned.

The breakdown in the vast structure has been ongoing, bits and pieces of news that added further dismay to an already dismal 2020. A support cable detached in August, resulting in an evaluation from the University of Central Florida, which manages the site. Replacement auxiliary cables were then on the way, temporary cables available, but on November 6 another main cable broke. The stresses on the second cable evidently told the story, making it clear that to proceed with repair would be to push against acceptable standards of safety.

Ralph Gaume, director of NSF’s Division of Astronomical Sciences, sums up the situation:

“Leadership at Arecibo Observatory and UCF did a commendable job addressing this situation, acting quickly and pursuing every possible option to save this incredible instrument. Until these assessments came in, our question was not if the observatory should be repaired but how. But in the end, a preponderance of data showed that we simply could not do this safely. And that is a line we cannot cross.”

Image: Arecibo Observatory’s 305-meter telescope in November of 2020. Credit: University of Central Florida.

It’s going to take some time for me to get my head around losing Arecibo, which has been since the early 1960s a part of my mental landscape when contemplating our civilization and its context in the cosmos. I had gotten to thinking in terms of ‘Arecibos’ of transmitting power, meaning that a dish like Arecibo could pick up an installation of comparable power over a span of 1,000 light years, a volume in which there are more than 10,000,000 stars. Ideas like that fueled my interest in SETI, which grew into a general passion for exoplanet research.

Remember, although we sometimes hear 51 Pegasi b referred to as the first exoplanet discovered, the honor actually belongs to the planets at the pulsar PSR B1257+12, which were found three years earlier in 1992 by Aleksander Wolszczan and Dale Frail using Arecibo data (51 Pegasi b was the first exoplanet found around a main sequence star, a valid distinction since pulsar planets are an unusual extreme as we contemplate the conditions extant in planetary systems). Speaking of pulsars, the first binary one was uncovered in Arecibo data in 1974 by Russell Hulse and Joseph H. Taylor, Jr., a find that earned the duo the Nobel Prize for Physics in 1993.

Arecibo has produced radar maps of Venus and Mercury and has charted near-Earth asteroids. As far back as 1965, it uncovered the actual rotation rate of Mercury (59 days as opposed to the previously believed 88). It analyzed the pulsar from the Crab Nebula supernova remnant in 1968 and performed the first radar ranging to an Earth-crossing asteroid (1862 Apollo) in 1980. Its planetary radar found evidence for hydrocarbon lakes on Titan and the observatory was used to study frequencies in the 1,000 MHz to 3,000 MHz range as part of the SETI effort.

Indeed, the list of accomplishments is far too long to list here, so I’ll direct you to this summary page. I do want to mention in the SETI context (although it was a matter of transmitting rather than listening) the 1974 message sent toward the globular cluster M13 by Frank Drake, primarily performed, I’m told, as a way of demonstrating what newly installed equipment could do. Even so, that transmission is an oft-cited marker in our thinking about our own place in the universe and the possibility of other technological civilizations we might encounter.

Invariably I think of Jill Tarter in terms of SETI, in this context because of her involvement in Project Phoenix, which moved to Arecibo in 1998 after stints at Parkes (Australia) and Green Bank (WV). As soon as I learned of Arecibo’s decommissioning, I wrote to ask for a comment. My own reflections on Arecibo hardly match the poetic depth of Dr. Tarter’s response:

I’ve been going to Arecibo since 1978. Over the decades, we’ve built a lot of Arecibo-specific hardware, written a lot of software, and bent the telescope control system into modes it was never designed for.

Arecibo was an impressive feat of engineering, a scientific workhorse, and it never lost that aura of being slightly exotic, no matter how many times I visited there; the constant croaking of the coquis [a frog common to Puerto Rico], the perfumes of the tropical forest, the local Ron del Barrelito [a rum said to be the best on the island], the Gregorian dome with its unmistakable compressor cadence, the jogging track underneath the dish ringed with small orchids, Orion rising over the treetops as seen from the balcony of the VSQ [Visiting Scientists Quarters], before heading off to my midnight shift of Project Phoenix observations, and the absolutely best view on the island from atop the platform.

But most of all I remember the staff and the resident scientists who were very close knit, offered us superb technical support, and threw wonderful parties with lots of dancing. It is very sad to witness the passing of this scientific Queen. She withstood powerful hurricanes, but age appears to have gotten the upper hand.

Arecibo’s demise also led me to touch base with Greg Matloff (New York City College of Technology (NYCCT)), whose work on interstellar propulsion was what originally drew me to the field (his Starflight Handbook, written with Eugene Mallove, was a frequently consulted text and provoked the research that led to my Centauri Dreams book in 2004). We had discussed Arecibo’s role in planetary protection in many conversations. Said Matloff:

“The loss of Arecibo is heartbreaking. This observatory has contributed so much to the study of Earth’s upper atmosphere, Solar System and deep sky objects, and SETI. But its greatest significance today is its service as planetary radar. Much of what we know about Near Earth Asteroids that might someday impact the Earth is due to the imaging capabilities of this instrument. It is my hope that an upgraded Arecibo can be constructed at the same site to continue this work of Earth Defense.”

That’s a hope many of us share, and we will see what comes of it. I do notice in the National Science Foundation’s materials on the decommissioning that NSF intends “to restore operations at assets such as the Arecibo Observatory LIDAR facility — a valuable geospace research tool — as well as at the visitor center and offsite Culebra facility, which analyzes cloud cover and precipitation data. NSF would also seek to explore possibilities for expanding the educational capacities of the learning center.”

What may emerge following telescope decommissioning is worth pondering.

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{ 22 comments… add one }
  • Thomas R Mazanec November 20, 2020, 10:34

    At least there is Tianyan in China to carry on the torch.
    https://en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Spherical_Telescope

  • Hal Schirmer Esq November 20, 2020, 10:44

    It’s NOT lost. We know exactly where it it.
    It requires replacing 2 steel cables.

    That will cost, eh, 1% of the revenue that Facebook or CNN or MSNBC makes today?

    • Jake B November 24, 2020, 8:36

      I wish it were that easy. Unfortunately failure of two cables is the least of the sites issues. First is the safe re-installation of the support cables. Having work crews on the unstable platform to install new cables is a serious risk to life (and a gamble none would be willing to make) due to the below issues.
      The unfortunate fact is as such: corrosion and failure of the support structure is not limited to just one cable or tower. Each and every cable on the site has been neglected for at least a decade now. With two failed cables, the remaining cables are supporting an increased load with the same decaying hardware and structure. If anything else, the time to subsequent failure has been shortened by the loss of two cables.
      Another issue the site is having is the load at which the second cable failed. From what I heard (I’m sure there was an article on it somewhere), the second cable failed at 66% of it’s installed capability. This could indicate the site is closer to failure than originally thought and only one or more cables failing (which is more likely now due to the increased load) to total structural failure. This also means that every cable would need to be replaced or risks mitigated to become safe again.
      The final factor that we have to keep in mind is that the platform isn’t the same mass as built. The platform underwent a retrofit to install the geodesic dome which added a load significant enough to warrant the installation of additional support cables. With the suspected decrease in safe working load of the support cables, the tolerance of available load (factor of safety) is too small to safely begin repairs.

      Overall, engineers have likely deemed the risks to life and instability of the structure too great to warrant attempts to recover the aging equipment.
      It is a shame to see it go, but after looking at the situation I’d say it is the most responsible course of action.
      Our only hope now is that the need for the equipment will be enough to construct a new radio telescope to fill its role.

  • Joe H. November 20, 2020, 13:44

    I know it’s merely coincidence the structural problems of the aging telescope have come to light during this plague year. And yet in some ways Arecibo seems to reflect greater themes of decline and decay. The scientist/historian Peter Turchin is the latest in a long line of pessimistic prophets.

    https://www.theatlantic.com/magazine/archive/2020/12/can-history-predict-future/616993/

    How long before someone Photoshops a fallen Arecibo with the jungle encroaching, and lyrics of Ozymandias superimposed on the scene?

    • Paul Gilster November 20, 2020, 15:59

      Also eerily reminiscent of such J. G. Ballard stories as “The Dead Astronaut,” etc.

  • Patient Observer November 20, 2020, 14:38

    Sad, but good things die of old age if fortune is good. However, the pioneering concept is reincarnated in China:

    https://www.nature.com/articles/d41586-019-02790-3

  • Alex Tolley November 20, 2020, 15:51

    I am in two minds about this. Arecibo is an instrument from the past. If it truly has advantages over newer approaches, the Chinese have just finished their own version that eclipses Arecibo in size, and presumably in performance.

    I recently watched the Seti Institute live webinar on the future of telescopes, primarily about distributed radio telescopes. The speakers were unanimous is stating this was the future – lots of cheap receivers whose signals could be combined to make a very powerful radio telescope.

    If they are correct, venerating Arecibo is rather like fetishizing an IBM 360 mainframe computer despite computing replacing such machines with racks of cheap computers in server farms, and even distributing computations out to the “edge”.

    Brits still venerate steam engines like the “Royal Scotsman” even though the age of steam is long over and been replaced by diesel and electric trains. Many people still prefer the elegance of sailing ships over modern cargo ships that eschew wind power. There are those who still enthuse over the Saturn V rocket, even though it has long gone and newer rockets will likely surpass its performance.

    There is also a sadness in that it was a historic telescope, shown in relevant movies like “Contact”, and also as a backdrop in the James Bond movie – “Goldeneye”. It is as famous in its way as the 200 inch Hale telescope at the Palomar Observatory.

    One day the age of rockets soaring into the sky will end, replaced by far more elegant approaches of reaching orbit and traveling beyond to deep space. Yet many will still pine for the spectacle of the rocket age, with pictures and paintings adorning offices and living rooms with scenes of fiery takeoffs. And like Picard gently touching the Phoenix, we still haunt aerospace museums and marvel at aircraft from the first half-century of flight.

    • Henry Cordova November 20, 2020, 18:38

      The theoretical performance of any telescope, radio or optical, is determined solely by its aperture. You can upgrade an instrument by increasing the sensitivity of its detectors, or the precision of its mounting, or by resilvering or coating its surface. But once the accuracy of its lens or mirror’s figure relative to the wavelength it operates at is optimized, it cannot be fundamentally improved upon. There are optical telescopes well over a century old today which can still do valuable research, although they may have been overhauled mechanically and electronically several times since their “first light”. The 100″ Hooker reflector was not scrapped the day the 200″ Hale opened. In fact, the Mt Wilson instrument boasts a better paraboloid than the Palomar Telescope. For the same reasons, radio telescopes can be upgraded to modern specs, and even if they are eclipsed by bigger instruments today, they can still be useful in applications where sheer size is not critical. The major advantage of the Arecibo dish was the geological feature over which it was constructed. Unless this can be duplicated cheaply somewhere else, there may be very good reason to repair the old girl rather than build a replacement at another site.

      It may be that the collapse of the structures suspended over the mesh disk may have damaged it so much that it can no longer be economically or safely repaired. If that is the case, then so be it. But age or technological obsolescence alone is not sufficient reason to abandon the site.

    • David November 21, 2020, 1:49

      Alex,
      There will always be a need for single dish antennas such as Arecibo because they will detect radiation that will be missed by aperture synthesis telescopes such as the VLA or ALMA. The latter do not detect radiation at all spatial scales, particularly from sources that are extended in size.
      If you want more see: http://articles.adsabs.harvard.edu//full/2002ASPC..278…27E/0000034.000.html

    • Alex Tolley November 21, 2020, 15:28

      @Henry, @David

      If I have misunderstood this SETI talk then I stand corrected. However, the 2 speakers appear to me to be saying that multiple, linked, receivers in arrays, like the SKA, are far more sensitive AND have a better field of view than the largest single-dish radio telescopes, AND that they are steerable too. I certainly do not have the expertise to tell if what they are saying is misleading, but I trust the SETI organizers to put on speakers who are credible experts.

      Radio Astronomy: The End of Big Dishes?

  • ole burde November 20, 2020, 16:26

    Responsible maintenance is to keep ´´the old one´´ working , NO MATTER WHAT , until ´´the new one ´´ is a certified sucses ……but thats just oldfashioned little me , grandfather-talk

  • charlie November 20, 2020, 17:45

    “Its planetary radar found evidence for hydrocarbon lakes on Titan …” , Is that true ? This radio telescope ACTUALLY was able to detect a liquid hydrocarbon Lake on a tiny moon like Titan? That seems like an awfully small target as well as a extremely distant one. How did it manage that feat?

  • Michael Fidler November 21, 2020, 4:14

    We can put the blame on many things but global warming has caused more problems around the globe at many observatories. The hurricanes and wild fires have destroyed or have come close to destroying many observatories and it is only going to get worst. Sad we live in such conflicting days.

  • Henry Cordova November 21, 2020, 13:58

    In praise of the “Starflight Handbook”

    I too have a copy of the Matloff/Mallove work, and it is indeed a useful and oft-consulted reference.

    But my copy was published in 1989, over thirty years ago! It must be way out of date. Surely there has been much progress in this field since it appeared. Are there any newer, revised editions available, or any other comparable volumes which examine this field for today’s readers?

    • Paul Gilster November 21, 2020, 21:42

      I wish we could get Wiley to publish a new edition of The Starflight Handbook, but evidently it won’t happen. Kelvin Long wrote Deep Space Propulsion in 2011 (it’s a Springer title). Like the Matloff book, it offers a wide survey of the available technologies. Greg’s Deep Space Probes is invaluable and in its second edition.

  • Alex Tolley November 21, 2020, 19:24

    SETI Institute: Tour the Arecibo Telescope youtube video.

  • safely anon November 21, 2020, 21:43

    Keep up the good work Paul & everybody, I’ve appreciated the last several posts.

    The loss of Arecibo I don’t understand. It would be one thing if they were to say that we don’t need it anymore because it fulfilled its mission, but just saying it can’t be repaired? That’s not much to go on. How was it constructed? What’s the wider context on its usefulness in the future? I see some disagreements about this above in the comments but it would be nice to have a more reputable source!

    • Henry Cordova November 22, 2020, 16:48

      I may not be a “reputable source”, but here’s what I know about the Arecibo Instrument.

      The stationary 1000 foot parabolic dish takes advantage of a natural sinkhole in the limestone of that part of the island. The towers that suspend the transmitter/receiver at the focus of the parabola can (to a certain extent) “steer” the dish by moving the focus around, using long movable cables. They are conveniently perched on hills surrounding the depression. Although the instrument was originally designed for ionospheric studies, directly overhead, the “beam” can be pointed in different directions, albeit at some loss of effective aperture. The dish is wire mesh suspended in the sinkhole, shimmed up in order to provide the appropriate parabolic figure.

      Its a clumsy arrangement, but its a 1000 foot dish, the largest in the world, without the complex, expensive and delicate altazimuth mount required for a fully steerable antenna. Its radio-quiet remote location and low latitude allow it to cover large areas of the celestial sphere.

      No doubt Arecibo could be rebuilt somewhere else, but it will be expensive. I know nothing about the Chinese alternative being constructed now.

  • Jeff Brandt November 22, 2020, 1:48

    I reside in Puerto Rico and there is a chance to save it! We just need to convince the NSF to relinquish control to the UCF, UAGM, NASA and other interested parties and allow them to continue without dependence on NSF funding. The Army Corp of Engineers is willing to attempt the repair. The new cables, already bought and paid for. Our representative just sent a letter to Congress asking for intervention.

    https://twitter.com/RepJenniffer/status/1329894249182208000
    https://www.change.org/p/united-states-national-science-foundation-nsf-repair-the-arecibo-observatory-do-not-decommission-it

  • xcalibur November 22, 2020, 12:13

    It’s bittersweet when things come to an end. I understand that Arecibo did alot of good work and had a long run; on the other hand, safety must come first. perhaps it can be rebuilt better than before, who knows? what matters most is that we continue to further our understanding of the cosmos, whatever it takes.

  • Afterthought November 22, 2020, 22:46

    Build one in a crater on far side of the moon.

    Telerobotically.

  • Richard November 23, 2020, 20:36

    Sooner or later, one of these was going to need to be dismantled. Perhaps another powerful may be built. Perhaps orbital based telescope would be better.

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