The Battle For Arecibo Has Been Lost

It is with a heavy heart that we must report the National Science Foundation (NSF) has decided to dismantle the Arecibo Observatory. Following the failure of two support cables, engineers have determined the structure is on the verge of collapse and that the necessary repairs would be too expensive and dangerous to conduct. At the same time, allowing the structure to collapse on its own would endanger nearby facilities and surely destroy the valuable research equipment suspended high above the 300 meter dish. Through controlled demolition, the NSF hopes to preserve as much of the facility and its hardware as possible.

Section of the Arecibo Message

When the first support cable broke free back in August, we worried about what it meant for the future of this unique astronomical observatory. Brought online in 1963 as part of a Cold War project to study how ICBMs behaved in Earth’s upper atmosphere, the massive radio telescope is unique in that it has the ability to transmit as well as receive. This capability has been used to produce radar maps of distant celestial objects and detect potentially hazardous near-Earth asteroids.

In 1974, it was even used to broadcast the goodwill of humankind to any intelligent lifeforms that might be listening. Known as the “Arecibo Message”, the transmission can be decoded to reveal an assortment of pictograms that convey everything from the atomic numbers of common elements to the shape of the human body. The final icon in the series was a simple diagram of Arecibo itself, so that anyone who intercepted the message would have an idea of how such a relatively primitive species had managed to reach out and touch the stars.

There is no replacement for the Arecibo Observatory, nor is there likely to be one in the near future. The Five hundred meter Aperture Spherical Telescope (FAST) in China is larger than Arecibo, but doesn’t have the crucial transmission capability. The Goldstone Deep Space Communications Complex in California can transmit, but as it’s primarily concerned with communicating with distant spacecraft, there’s little free time to engage in scientific observations. Even when it’s available for research, the largest dish in the Goldstone array is only 1/4 the diameter of the reflector at Arecibo.

Just last week we wondered aloud whether a nearly 60 year old radio telescope was still worth saving given the incredible advancements in technology that have been made in the intervening years. Now, unfortunately, we have our answer.

98 thoughts on “The Battle For Arecibo Has Been Lost

  1. Just a thought… but the best place to build a giant radio telescope, is in space where you are not constrained by corrosion and gravity. Or for instance on the moon minimally constrained by gravity.

    1. Yes, but if we lost the battle with people to spend the money to fix Arecibo here on Earth, how hard would be this battle with them to spend the necessary money to build a observatory in the moon / orbit ?

        1. Can you share any sources on the history of Arecibo you would recommend? I hadn’t considered the military applications of radio astronomy, but given that it exists, I’m not surprised there were some.


            The origins of the observatory trace to late 1950s efforts to develop anti-ballistic missile (ABM) defences as part of the newly formed ARPA’s ABM umbrella-effort, Project Defender. Even at this early stage it was clear that the use of radar decoys would be a serious problem at the long ranges needed to successfully attack a warhead, ranges on the order of 1,000 miles (1,600 km).[15][16]

            Among the many Defender projects were several studies based on the concept that a re-entering nuclear warhead would cause unique physical signatures while still in the upper atmosphere. It was known that hot, high-speed objects caused ionization of the atmosphere that reflects radar waves, and it appeared that a warhead’s signature would be different enough from decoys that a detector could pick out the warhead directly, or alternately, provide added information that would allow operators to focus a conventional tracking radar on the single return from the warhead.[15][16]

            Although the concept appeared to offer a solution to the tracking problem, there was almost no information on either the physics of re-entry or a strong understanding of the normal composition of the upper layers of the ionosphere. ARPA began to address both simultaneously. To better understand the radar returns from a warhead, several radars were built on Kwajalein Atoll, while Arecibo started with the dual purpose of understanding the ionosphere’s F-layer while also producing a general-purpose scientific radio observatory.[15][16]

      1. It’s really not a battle over funding.

        At some point your your structural components are sufficiently fatigued that a “repair” is indistinguishable from tearing the old one down and starting new.

          1. Some parts require you to pull the whole ship apart in the dry dock. For example, the hull frame.

            You don’t want to go through the trouble to replace a single part when there are five hundred other parts that would need replacing shortly after. Repairing the thing bit-by-bit comes more expensive and puts it out of service each time.

            You keep replacing the parts that fail regularly, until eventually the other parts start to catch up in wear and tear and everything starts to fail at once. You end up spending more time and money fixing it than using, so you have to choose: rebuild the whole thing, or just tear it down and make another.

          1. Some are, some aren’t.

            Fat cells take about ten years to regenerate, the lining of your gut replaces every few days. The cells in your heart muscles replace about four times in your lifespan, but they do it faster when you’re younger than when you’re old.

            Some cells never replace. There’s a myth that brain cells don’t, but recently it’s been found out that you generate about 700 new neurons a day. That’s not very much, but they do re-grow.

      1. Shh… you have to give the people their excuse for investing their emotions and/or money in Elon Musk’s big rocket…

        Seriously though. I’ve seen the “Just put it up in orbit” argument pop up a lot recently, from people who actually seem to think it wouldn’t cost the budget of a medium-sized nation to do so.

        1. Disregard Elon for a moment.

          Do you deny that Falcon 9 is the cheapest medium-to-heavy launch vehicle in the world and currently one of the most reliable after ULA’s Atlas family which is slowly being deprecated and horrendously expensive Ariane 5. while having galore of gigantic customers like Iridium and SES and US’s DoD and NROL.

          Or do you deny that Falcon Heavy is currently most powerful rocket in the world by factor by two while being cheaper than the Atlas family while being actually obtainable/contractable by international customers!! (E.g. it is not some US goverment sponsored unobtanium.)

          They have incredible product in medium to heavy launch market and they surely worked hard for it.
          You might consider Starship as Elon’s plaything but even if you disreagard it SX does have unmatched products in their market and I sincerely hope that more private non-heavily-subsidized medium-to-heavy launchers will pop around a world and really hope that some of the are going to be EU based (this is my wet dream).

          1. It’s anyone’s guess what a Falcon 9 and the launch logistics actually cost, since SpaceX isn’t a publicly traded company and they don’t have to release the information. Musk can claim the price to be anything he wants – while each launch is subsidized by investor money, cheap government loans, and twice overpriced NASA contracts.

            The rest is irrelevant to the point. Even the optimist would have to concede that SpaceX is still too expensive to put a gigantic anything to orbit.

    2. Assuming that you could find a novel way to pack and deploy a reflector 300m wide, then the problems it has are essentially the same as other space telescopes: launching it, orienting it, keeping it stable, keeping it powered and functional, etc. The James Web space telescope is a ~ $9 billion project, so this should be in a similar ballpark.

      1. Moon would be an ideal spot. Not geologically active, no atmosphere, low gravity. Plus since it rotates slowly compared to Earth, you could pick a spot and continue to receive signal from the same spot for hours vs a few minutes on Earth.

        1. The moon is actually bombarded by micrometeorites all the time, since it is a body with significant gravity. The surface has wild temperature swings from boiling hot to liquid methane cold, which makes steel components unworkable because they would just turn brittle and snap.

      2. For the kind of astrophysics studied with the telescope perhaps the better question is, does it make ANY difference if it happens now, or 100 years from now? And if not, perhaps a space telescope will be an easy thing 100 years from now.

        It is too bad Musk is not interested in the Moon (and Mars is too windy). A steerable dish on the Moon can be huge plus no wind loading. Also, with no atmosphere there is full signal strength from horizon to horizon and a two week uninterrupted integration time is possible. Plus the “dark” side is shielded from Earth radio noise. Why would anyone build an Earth based scope at this time when Lunar/Space ones are likely just around the corner?

        1. If you know what was meant then it’s a word with a meaning. In English we have many words with multiple meanings. At some point “lacking in illumination” ceased to be the only meaning of “dark”.

          Besides, “dark side” sounds cooler and in a democracy that just might mean more funding.

      1. And no atmosphere means no attenuation, particularly by water. Besides, little holes in a reflector are trivial. Be wrecked by a perfect hit on major components much less likely than a major hurricane destroying the thing.

        Plus you can bury nearly all critical equipment under 12 meters of regolith which will have the weight of 2 meters of soil on Earth. The structure of the whole rig has to support less than 1/6 the mass of an Earth telescope, so it all gets simpler.

        But seriously, why even bother planning? When Emperor Xi militarizes the Moon, China will control all access to Earth orbit and beyond.

          1. China isn’t the middle east or Africa. You can’t just pay for an insurgency and send NATO bombers after the leadership.

            Well, you can, but you’ll start the third world war.

        1. it is always so easy for poor people like you (and me) to play the game “make me wish if i had…”: because we have not, we fell free to be generous with the money that we don’t have. Lets play this game: find a project you can found whit a sum you have (lets say 10K USD? 1000 USD? 100 USD?) and than DONATE that sum for real. When it was the last time you did? if the reply is similar to “I never did”, well, stop to say “make me wish I had…”.

          1. Why not look at donating as a percentage of total income. I am far below the poverty line and still donate about 0.05% of my income to various local food banks generally. It’s not much more than a couple hundred a year. What if a billionaire donated 0.05%? Poor or not poor, wishing or not wishing is irrelevant to being about to throw a percentage of income one can easily afford at goodwill, and in this case valuable scientific research. The abandonment of this dish might be a mistake for all we know. There’s a difference between greed and not being able to afford things. The ditching of this project reflects exactly that about our world.

  2. Something that isn’t usually mentioned, Arecibo isn’t just the reflector and RF gear, the quiet zone around it was a great achievement as well and very hard to maintain.
    I wonder if starlink had any weight on the decision as well.

    1. Yeah, that’s roughly what I’m thinking. What’s the sell-off here? These things always have a layer or two. SOMEBODY in the world would’ve bought such a thing and put up some chickenwire if not.

  3. How difficult would it be to add transmission capability to the Chinese one? I don’t know anything about it but I would think the dish and feed is the main complicated/expensive part. Adding a transmitter next to the receiver may be not a very expensive upgrade?

    1. The reason no other terrestrial radio telescope build transmission capability is because it wasn’t actually genuine. It was a mechanism to transmit PR to humans on this rock, not DNA helices to greys on other rocks. The Arecibo message was transmitted for a few minutes to a very narrow part of the sky—at an amplitude which would have never risen above the SNR required to dominate the star we’re orbiting. Even as a directional broadcast. No other star could have received it, even our nearest neighbors. And that doesn’t even get into the likelihood of the timing. They could at least have sent it a few more times each year until it fell apart if they were serious.
      It was a gimmick that they did because they inherited cold war hardware designed for something else, so they figured they may as well fire up the TX for some grant money or something. Or to inspire the kids. I’m not saying it was totally cynical—popularity is valuable to science. But this was not a genuine attempt to reach other life. Not by a few orders of magnitude.

      A different study was done in the sixties. I believe the scientist involved was with nuclear space propulsion, and some supervisor tasked him to do the math and figure out what it would take to send a receivable omnidirectional signal at a low, Morse code-like baud rate that would reach about five to ten light-years out. It would reach proxima centauri and transmit a few words of data. Wanna know what the solution was? To put together a massive, nuclear-propelled booster stage and ship a pile of our surplus H-bombs into Jupiter orbit at about the altitude of Io. By using Jupiter’s nasty Van Allen belts as an amplifier of some kind, they would set the H-bombs off in space and let the EMP resonate through a magnetic field nearly as big as a small star’s. They would time out the detonators to basically do Morse code. With a MASSIVE fusion-powered key. Biggest radio signal we’d ever make in history. Dit dit dit… dit dit dah… dit dah dah dit. That’s about it. Each pulse at ten megatons or so, spaced as far from our noisy sun as we can manage and slowed down so it could echo around in Jupiter’s ears until the pulse decays. That might barely pick up one star over.

      THAT is what a real interstellar message would require. Naturally they never decided to do it (or even build an Orion, luckily) and the Fermi paradox puzzles me because why the hell would anyone else out there do it? So no, nobody is really rigging up another radio telescope to transmit. That stunt has been played out.
      In short, aliens are not watching old re-runs of I Love Lucy. That’s a myth. Radio waves travel a long ways, but they have to compete with noise. They aren’t hearing Arecibo either.

      I mean I suppose there are other astronomy uses for TX as well, like trying to radar some near-Earth asteroids. I can’t say much about that part. I think you’d want to pick them up optically—if you can bounce radar off them, it’s probably way too late. Would be kind of like a bat using echolocation to dodge a bullet or something silly like that. Splat.

      1. The importance of the transmission capabilities is all about being able to radar asteroids. Like you said the message was just a PR stunt. Being able to shine a few megawatts of radio power at an object in space is very useful for determining it’s speed and position. A few near earth asteroids have been ruled out as collision candidates specifically by arecibo. I’m not sure why you would think picking them up optically would be better.

      2. You frankly don’t know what the heck you’re talking about. Of course there are other uses for transmission and they’re mentioned in the brief above. Arecibo is regularly used in near asteroid observations, so much so that its our current best instrument to do so if the object is within view. Its also often used for Venus observation when possible –

        The loss of Arecibo will not be small to the scientific community.

      3. Again the “cold war” issue is something I never heard before this recent talk of closing Arecibo.

        Even wikipedia seems to suggest experiments about the ionosphere, not directly missile detecting.

        Yes the “contact alien life” transmission was a “gimmick”, but it happened because Arecibo could transmit. The function may not be too useful, but it’s been there for almost sixty years, and now it’s not.

        Tye transmit function was definitely used for some specific things.

  4. Somebody just had to bring politics into the discussion. Are you forgetting the current President is the one who established the Space Force, has supported the military budgets, has reinvigorated Detroit, the coral mines, and small businesses? The former president, whose name I must not be mentioned, never spent a penny on infrastructure so what makes you think his underling would do anything even remotely similar to this kind of project?

    1. You mean the one who wanted to cut the NSF budget by 6.5%. You mean the anti-science, climate denying, anti-vax one currently in office. He could not even spell science, never mind support it

  5. “The Five hundred meter Aperture Spherical Telescope (FAST) in China is larger than Arecibo, but doesn’t have the crucial transmission capability. ”

    I guess transmission isn’t so crucial if they decided not to add the feature. ET will be disappointed…3000 years from now

    1. Because the Chinese people are concerned only with humanity and incapable of making mistakes…?

      Seriously please explain your “logic”, how do you get from “China doesn’t care” to “it must not matter”?!?! China doesn’t care for human rights or freedom of speech, do those also not matter?

  6. As I expected. They didn’t even really try, I think.
    Rather, it seems to be very convenient for them that the caused damage possesses a risk. Now they can demolish the telescope quickly, before any other solution has a chance pop up. I just hope that the site becomes more than a cheap memorial place that’s left to rot. Hopefully, they use it wisely, maybe even install an astronomy fascility or operate a small radio telescope there. Or maybe something else, that inspires people.

  7. Damn it, now that the phone is off the hook, if they ever call back looking for lesson plan part 2 all they will get is static:

    We sent a 3 minute long message from Arecibo:
    20 trillion Watts (effective isotropic radiated power) – ~133 dBm
    It was sent on the 16th of November 1974 at 1 AM AST (Atlantic Standard Time) or 05:00 UTC and was aimed at where the globular star cluster M13 (was at that time, they have moved since, or will have had moved by the time the message arrives).

    We taught them to count up to 10 in binary.
    We showed them the five secret elements used in our DNA.
    We told them how many nucleotide base pairs we believed were in the human genome
    (we were wrong by 1.1 billion, only out by 34% – that was close enough)
    We flashed them the structure of our double helix.
    We showed them the size of an average US male.
    We gave them our actual real home address.
    (but back then we included Pluto as a planet, so maybe if they pop by some day they will go a different solar system, one without a dwarf planet).
    We even sent them the size of our telephone!

    It will take about 22200 years to get there and then another 22200 for the reply, we need to form a committee and action this right away it needs to be solved by the year 46420 or at the very latest maybe 46421. The freespace path loss over 22.2 kly is roughly 446.4 dB, we are going to need a much much bigger antenna, like really really really really big. About 0.0022 light years wide 0.00067 parsecs wide or 140 astronomical units diameter would give an antenna gain of about 253 dB, and that should work. What is that about 140 AU, so the distance from the earth to the sun by 140, you could get buy in from the military (space force) as a planet destroyer.

    1. It had some flaws, one was it could only point where the earth pointed it in the sky. So if some space stone was coming at the Earth, there are high odds that it not have be seen, especially because it is not emitting radio waves :)

        1. It is a spherical dish, which are not common so it has multiple focal points, or should that be focal spheres. Lowering the receiver increases the frequency or increases the gain of higher frequencies, raising the receiver lowers the frequency or increases the gain of lower frequencies. Moving it about points it at a few different places in the sky within a forty-degree cone, but the further you moved it from the center the lower the gain will be because less signal is hitting the dish and being focused to that area. But it works 24 hours a day, can not do that with optical.

          Time to watch anything with the Arecibo Observatory in it.
          The X-Files television episode “Little Green Men” (1994, Season 2, Episode 1)
          GoldenEye (1995)
          Species (1995)
          Contact (1997)

          Of course the X-Files were there first, and opened the door.

    1. Yes. It’s already the setting of several movies. Which is exactly why they should have opted to save it. Science costs money and for too many voters and congressmen this was probably the only observatory they could name if you asked them.

      I wonder what Paul Allen would do if he were still alive.

        1. Who says ripping it out and starting over isn’t saving it? Keep the name, keep the location build a new dish. Continue to call it Arecibo. That’s the part that really counts. Which part makes it grandfather’s axe? The name, it’s what you choose to call it.

          But I didn’t read anything about starting over. Did I miss that part? I thought they were just going to rip out the dish then mothball everything else indefinitely.

          If they are rebuilding then they shouldn’t talk about tearing down Arecibo and replacing it. They should talk about repairing the Arecibo telescope, by replacing it’s dish. What’s the difference? Just a name. But it’s a famous name.

          As I type this I misspelled Arecibo. How did I catch it? Apparently Arecibo is in Firefox’s dictionary. That kind of makes my point right there. It’s well known.

          1. Yes we should consider the Google spelling dictionary when making complex financial decisions involving politics and technology, maybe we can also crack open some fortune cookies.

  8. So here’s my most recent thought on how Arecibo could be fixed without too much risk to human life.

    1. Use a helicopter to lower a “cap” onto the top of the tower with the broken suspension cables. The purpose of the cap will be to “capture” a temporary replacement cable laid over it.

    2. Use a helicopter to lower the temporary replacement cable into place. The suspended end of the cable will have a grappling hook to catch on the frame of the instrument structure. Once this has been positioned, then the cable is drawn over the previously-placed cap, and then further out to a point at which it can be tensioned from.

    Supposing that it’s not practical to lift a cable of the appropriate diameter, you could still do the same thing with a lighter weight cable, except that it’s not a single cable but rather a cable with a pulley and anchor at the grappling hook, together with another cable going through the pulley and anchor. To this second cable, once it has been laid out and positioned, you’d attach a larger cable, and then draw it up using the pulley until it clips into the anchor.

    Anyway, just some random ideas to throw at the wind. I read that the design of the Arecibo dish is obsolete, so maybe a complete tear-down and rebuild with a more modern design may be appropriate.

  9. Sad times and i dont really understand why the likes of Nasa & ESA dont just get together to raise some money for it, heck, get hollywood involved since they love the location so much.

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