They Want To Put A Telescope In A Crater On The Moon

February 6, 2024 by Lewin Day 30 Comments

When we first developed telescopes, we started using them on the ground. Humanity was yet to master powered flight, you see, to say nothing of going beyond into space. As technology developed, we realized that putting a telescope up on a satellite might be useful, since it would get rid of all that horrible distortion from that pesky old atmosphere. We also developed radio telescopes, when we realized there were electromagnetic signals beyond visible light that were of great interest to us.

Now, NASA’s dreaming even bigger. What if it could build a big radio telescope up on the Moon?

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Blame It On The Sockets: Forensic Analysis Of The Arecibo Collapse

August 29, 2023 by Dan Maloney 58 Comments

Nearly three years after the rapid unplanned disassembly of the Arecibo radio telescope, we finally have a culprit in the collapse: bad sockets.

In case you somehow missed it, back in 2020 we started getting ominous reports that the cables supporting the 900-ton instrument platform above the 300-meter primary reflector of what was at the time the world’s largest radio telescope were slowly coming undone. From the first sign of problems in August, when the first broken cable smashed a hole in the reflector, to the failure of a second cable in November, it surely seemed like Arecibo’s days were numbered, and that it would fall victim to all the other bad luck we seemed to be rapidly accruing in that fateful year. The inevitable finally happened on December 1, when over-stressed cables on support tower four finally gave way, sending the platform on a graceful swing into the side of the natural depression that cradled the reflector, damaging the telescope beyond all hope of repair.

The long run-up to the telescope’s final act had a silver lining in that it provided engineers and scientists with a chance to carefully observe the failure in real-time. So there was no real mystery as to what happened, at least from a big-picture perspective. But one always wants to know the fine-scale details of such failures, a task which fell to forensic investigation firm Thornton Tomasetti. They enlisted the help of the Columbia University Strength of Materials lab, which sent pieces of the failed cable to the Oak Ridge National Laboratory’s High Flux Isotope reactor for neutron imaging, which is like an X-ray study but uses streams of neutrons that interact with the material’s nuclei rather than their electrons.

The full report (PDF) reveals five proximate causes for the collapse, chief of which is “[T]he manual and inconsistent splay of the wires during cable socketing,” which we take to mean that the individual strands of the cables were not spread out correctly before the molten zinc “spelter socket” was molded around them. The resulting shear stress caused the zinc to slowly flow around the cable strands, letting them slip out of the surrounding steel socket and — well, you can watch the rest below for yourself.

As is usually the case with such failures, there are multiple causes, all of which are covered in the 300+ page report. But being able to pin the bulk of the failure on a single, easily understood — and easily addressed — defect is comforting, in a way. It’s cold comfort to astronomers and Arecibo staff, perhaps, but at least it’s a lesson that might prevent future failures of cable-supported structures.

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Moon Bouncing And Radar Imaging With LoRa

December 3, 2021 by Ryan Flowers 16 Comments

The LoRa radio protocol is well known to hardware hackers because of its Long Range (hence the name) but also its extremely low power use, making it a go-to for battery powered devices with tiny antennae. But what if the power wasn’t low, and the antenna not tiny? You might just bounce a LoRa message off the moon. But that’s not all.

The team that pulled off the LoRa Moonbounce consisted of folks from the European Space Agency, Lacuna Space, and the CA Muller Radio Astronomy Station Foundation which operates the Dwingeloo Radio Telescope. The Dwingeloo Radio Telescope is no stranger to Amateur Radio experiments, but this one was unique.

LoRa Moonbounce plotted for doppler shift by frequency — A radar image of the moon generated from LoRa Moonbounce

Operating in the 70 cm Amateur Radio band (430 MHz) meant that the LoRa signal was not limited to the low power signals allowed in the ISM bands. The team amplified the signal to 350 Watts, and then used the radio telescope’s 25 Meter dish to direct the transmission toward the moon.

The result? Not only were they able to receive the reflected transmission using the same transceiver they modulated it with — an off the shelf IOT LoRa radio — but they also recorded the transmission with an SDR. By plotting frequency and doppler delay, the LoRa transmission was able to be used to get a radar image of the moon- a great dual purpose use that is noteworthy in and of itself.

LoRa is a versatile technology, and can even be used for tracking your High Altitude Balloon that’s returned to Terra Firma.

Your Own 11.2 GHz Radio Telescope

February 12, 2021 by Al Williams 26 Comments

Modern life has its conveniences. Often, those conveniences lead to easier hacks. A great example of that is the rise of satellite television and the impact it has had on amateur radio telescopes. There was a time when building a dish and a suitable low noise amplifier was a big deal. Now they are commodity parts you can get anywhere.

The antenna in use is a 1.2-meter prime focus dish. Some TV dishes use an offset feed, but that makes it harder to aim for use in a radio telescope. In addition to off-the-shelf antenna and RF components, an AirSpy software-defined radio picks up the frequency-shifted output from the antenna. There is more about the software side of the build in a follow-up post. We liked that this was a pretty meaty example of using GNU Radio.

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SpaceAusScope Team Listens To The Galaxy

December 23, 2020 by Al Williams 2 Comments

Australia has always had a reputation for astronomy. It is a great site low in the Southern hemisphere and there are lots of sparsely inhabited areas free from light and radio interference. Some of the first video from the Apollo 11 landing, for example, came in from “the dish” — a very large radio telescope down under. Australian hobbyists have formed a group, SpaceAusScope, where teams across Australia are building radio telescopes with the plan — which has been delayed by the pandemic — of collecting data and providing it for public analysis.

A secondary goal of the group is to provide better documentation for amateur radio telescope builders. So even if you don’t live in Australia, you might want to check out their website. It looks as thoughthe documentation will arrive in the future, but there is a very informative blog post from one team member about the helical antenna design most of the teams are using to eavesdrop on the hydrogen line.

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Did ET Finally Call Us?

December 21, 2020 by Al Williams 73 Comments

An Australian radio telescope picked up unusual signals back in 2019 and thinks they originated from Proxima Centauri, a scant 4.3 light years from our blue marble. Researchers caution that it almost certainly is a signal of human or natural origin and that more analysis will probably show it didn’t come from Proxima Centauri. But they can’t yet explain it.

The research is from the Breakthrough Listen project, a decade-long SETI project. The 980 MHz BLC-1 signal, as it’s called, meets the tests that identify the signal as interesting. It has a narrow bandwidth, it drifts in frequency consistent with a signal moving away or towards the Earth, and it disappears when the radio telescope points elsewhere.

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Hackaday Links: November 22, 2020

November 22, 2020 by Dan Maloney 6 Comments

Remember DSRC? If the initialism doesn’t ring a bell, don’t worry — Dedicated Short-Range Communications, a radio service intended to let cars in traffic talk to each other, never really caught on. Back in 1999, when the Federal Communications Commission set aside 75 MHz of spectrum in the 5.9-GHz band, it probably seemed like a good idea — after all, the flying cars of the future would surely need a way to communicate with each other. Only about 15,000 vehicles in the US have DSRC, and so the FCC decided to snatch back the whole 75-MHz slice and reallocate it. The lower 45 MHz will be tacked onto the existing unlicensed 5.8-GHz band where WiFi now lives, providing interesting opportunities in wireless networking. Fans of chatty cars need not fret, though — the upper 30 MHz block is being reallocated to a different Intelligent Transportation System Service called C-V2X, for Cellular Vehicle to Everything, which by its name alone is far cooler and therefore more likely to succeed.

NASA keeps dropping cool teasers of the Mars 2020 mission as the package containing the Perseverance rover hurtles across space on its way to a February rendezvous with the Red Planet. The latest: you can listen to the faint sounds the rover is making as it gets ready for its date with destiny. While we’ve heard sounds from Mars before — the InSight lander used its seismometer to record the Martian wind — Perseverance is the first Mars rover equipped with actual microphones. It’s pretty neat to hear the faint whirring of the rover’s thermal management system pump doing its thing in interplanetary space, and even cooler to think that we’ll soon hear what it sounds like to land on Mars.

Speaking of space, back at the beginning of 2020 — you know, a couple of million years ago — we kicked off the Hack Chat series by talking with Alberto Caballero about his “Habitable Exoplanets” project, a crowd-sourced search for “Earth 2.0”. We found it fascinating that amateur astronomers using off-the-shelf gear could detect the subtle signs of planets orbiting stars half a galaxy away. We’ve kept in touch with Alberto since then, and he recently tipped us off to his new SETI Project. Following the citizen-science model of the Habitable Exoplanets project, Alberto is looking to recruit amateur radio astronomers willing to turn their antennas in the direction of stars similar to the Sun, where it just might be possible for intelligent life to have formed. Check out the PDF summary of the project which includes the modest technical requirements for getting in on the SETI action.

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