Intuitive Machines’ Nova-C Makes It To The Lunar Surface In US Return After Half A Century

February 23, 2024 by Maya Posch 57 Comments

Intuitive Machines’ first mission (IM-1) featuring the Nova-C Odysseus lunar lander was launched on top of a SpaceX Falcon 9 on February 15th, 2024, as part of NASA’s Commercial Lunar Payload Services (CLPS). Targeting a landing site near the lunar south pole, it was supposed to use its onboard laser range finders to help it navigate safely for a soft touchdown on the lunar surface. Unfortunately, it was this component that was found to have malfunctioned as the spacecraft was already in lunar orbit. Fortunately, there was a workaround. By using one of the NASA payloads on the lander, the Navigation Doppler Lidar (NDL), the mission could continue.

Perhaps unsurprisingly, the use of the NDL as a fallback option was considered before launch, and since its functionality overlaps with that of the primary laser range finders of Nova-C, it was pressed into service with a new configuration uploaded by IM operators back on Earth before Nova-C committed to a landing burn. Then, on February 22nd, the spacecraft began its descent to the surface, which also involved the Eaglecam payload that was designed to be released before snapping a self-portrait of the lander as it descended.

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Tool Demagnetizers And The Magnetic Stray Field

February 23, 2024 by Maya Posch 9 Comments

If you’ve ever found yourself wondering how those tool magnetizer/demagnetizer gadgets worked, [Electromagnetic Videos] has produced a pretty succinct and informative video on the subject.

The magnetizer/demagnetizer gadget after meeting its demise at a cutting disc. (Credit: Electromagnetic Videos, YouTube)

While the magnetizing step is quite straightforward and can be demonstrated even by just putting any old magnet against the screwdriver’s metal, it is the demagnetization step that doesn’t make intuitively sense, as the field lines of the magnets are supposed to align the (usually ferromagnetic) material’s magnetic dipole moments and thus create an ordered magnetic field within the screwdriver.

This is only part of the story, however, as the magnetic field outside of a magnet is termed the demagnetizing field (also ‘stray field’). A property of this field is that it acts upon the magnetization of e.g. ferromagnetic material in a way that reduces its magnetic moment, effectively ‘scrambling’ any existing magnetization.

By repeatedly moving a metal tool through this stray field, each time further and further away from the magnet, the magnetic moment reduces until any magnetization has effectively vanished. It is the kind of simple demonstration of magnetism that really should be part of any physics class thanks to its myriad of real-world uses, as this one toolbox gadget shows.

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The ELIZA Archaeology Project: Uncovering The Original ELIZA

February 22, 2024 by Maya Posch 31 Comments

Since ELIZA was created by [Joseph Weizenbaum] in the 1960s, its success had led to many variations and ports being written over the intervening decades. The goal of the ELIZA Archaeology Project by Stanford, USC, Oxford and other university teams is to explore and uncover as much of this history as possible, starting with the original 1960s code. As noted in a recent blog post by [Anthony Hay], most of the intervening ‘ELIZA’ versions seem to have been more inspired by the original rather than accurate replicas or extensions of the original. This raises the question of what the original program really looked like, a question which wasn’t answered until 2020 when the original source code was rediscovered. Continue reading “The ELIZA Archaeology Project: Uncovering The Original ELIZA” →

Using Gallium Oxide As A Resistive Memory Element

February 22, 2024 by Maya Posch 7 Comments

Resistive random-access memory (RRAM) is a highly attractive form of RAM, as it promises low-power usage with stable long-term storage, even in the absence of external power. Finding the right materials to create an RRAM cell which incorporates these features is however not easy, but recently researchers have focused their efforts on gallium(III) oxide (Ga₂O₃), with a research article by [Li-Wen Wang] and colleagues in Nanomaterials describing a two-bit cell (MLC) based around an aluminium-gallium oxide-graphene oxide stack which they tested for an endurance of more than a hundred cycles.

Filament models of the Al/GO/Ga2O3/ITO/glass device. (Credit: Li-Wen Wang et al., 2023)

The way gallium-oxide works in an RRAM cell is by forming a conductive filament formed by oxygen vacancies. These vacancies and the resulting conductive path are controlled by an externally applied current via the top (Al) and bottom (ITO) electrodes, with the graphene-oxide (GO) layer acting as a source of oxygen ions.

In related research, [Zhengchun Yang] and colleagues described in a 2020 article in Ceramics International how they constructed a device consisting out of gallium(III) oxide RRAM data storage with a piezoelectric ceramic element that served both as pressure sensor and power supply. The current generated by the piezo element is used to power the memory device and record measurements.

Then there is the somewhat more wild ‘FlexRAM’ idea pitched by [Ruizhi Yuan] and colleagues in Advanced Materials who describe how they created a device consisting out of flexible polymer called ‘EcoFlex’ with pockets in it for a ‘liquid gallium-based metal’ to create a flexible memory device. At millimeter-sized structures it’s hard to see practical applications for this technology, even if the associated PR article in IEEE Spectrum goes pretty hard on breathless speculation.

Car Driving Simulators For Students, Or: When Simulators Make Sense

February 21, 2024 by Maya Posch 69 Comments

There are many benefits to learning to fly an airplane, drive a racing car, or operate some complex piece of machinery. Ideally, you’d do so in a perfectly safe environment, even when the instructor decides to flip on a number of disaster options and you find your method of transportation careening towards the ground, or the refinery column you’re monitoring indicating that it’s mere seconds away from going critical and wiping out itself and half the refinery with it.

Still, we send inexperienced drivers in cars onto the roads each day as they either work towards getting their driving license, or have passed their driving exam and are working towards gaining experience. It is this inexperience with dangerous situations and tendency to underestimate them which is among the primary factors why new teenage drivers are much more likely to end up in crashes, with the 16-19 age group having a fatal crash nearly three times as high as drivers aged 20 and up.

After an initial surge in car driving simulators being used for students during the 1950s and 1960s, it now appears that we might see them return in a modern format.

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Stereo Photography With Smartphones Made Better With Syncing

February 21, 2024 by Maya Posch 16 Comments

Stereo photography has been around for almost as long as photography itself, and it remains a popular way to capture a scene in its 3D glory. Yet despite the fact that pretty much everyone carries one or more cameras with them every day in the form of a smartphone, carrying a stereo photography-capable system with you remains tricky. As [Pascal Martiné] explains in a How-To article, although you can take two smartphones with you, syncing up both cameras to get a stereo image isn’t so straightforward, even though this is essential if you want to prevent jarring shifts between the left and right image.

Custom made twin shutter. (Credit: Pascal Martiné)

Fortunately, having two of the exact same smartphone with the exact same camera modules is not an absolute requirement, as apps like i3DStereoid offer auto-adjustments. But activating the camera trigger on each phone is essential. The usual assortment of wireless remote triggers don’t work well here, and the twin-pairing in i3DStereoid had too much delay for dynamic scenes. This left the wired remote trigger option, but with a dearth of existing stereo trigger options [Pascal] was forced to make his own for two iPhones out of Apple Lightning cables and wired earbud volume controls.

Although the initial prototype more or less worked, [Pascal] found that each iPhone would often ‘decide’ to release the trigger at a slightly different time, requiring multiple attempts at the perfect shot. This led him down a rabbit hole of investigating different camera apps and configurations to make shutter delay as deterministic as possible. Much of this turned out to be due to auto exposure and auto focus, with enabling AE/AF lock drastically increasing the success rate, though this has to be done manually before each shot as an extra step.

With this one tweak, he found that most of the stereo photo pairs are now perfectly synced, while occasionally there is about a ~3 ms jitter, the cause of which he hasn’t tracked down yet, but which could be due to the camera app or iOS being busy with something else.

In the end, this iPhone-based stereo photography setup might not be as reliable or capable as some of the purpose-built rigs we’ve covered over the years, but it does get extra points for portability.

New Modelling Shows That Flat Protoplanets Might Be A Thing

February 20, 2024 by Maya Posch 23 Comments

Surface density of the benchmark run disc (in g cm−2). The disc becomes gravitationally unstable and fragments. Four of the fragments or protoplanets are followed until they reach density 10−3 g cm−3. (Credit: Fenton et al., 2024) — Surface density of the benchmark run disc (in g cm⁻²). The disc becomes gravitationally unstable and fragments. Four of the fragments or protoplanets are followed until they reach density 10⁻³ g cm⁻³. (Credit: Fenton et al., 2024)

While the very idea of a flat planet millions of years after its formation is patently ridiculous, recent modelling shows that during the protostar phase – where material from a nebula is drawn around a hydrostatic core into an accretion disc – it is likely that many of of the protoplanets which form inside a fragmentary protostar accretion disc take on a strongly oblate spheroid shape, rather than a spherical one. This according to [Adam Fenton] and [Dimitris Stamatellos], who ran half a million CPU hours worth of simulation time at the UK’s DiRAC HPC facility, per the University of Central Lancashire (UCLan) press release.

The research was published in the February 2024 issue of Astronomy & Astrophysics, titled The 3D structure of disc-instability protoplanets.

Where this research is essential is not just in our understanding of how our own solar system came to be – including our own oblate spheroid Earth – but also in interpreting what we observe via the Hubble Space Telescope, James Webb Space Telescope and others as we examine areas of the observable Universe such as the Orion Nebula, which is one of the regions with the most actively forming stars. By comparing these simulations with observations, we may find that the simulation matches perfectly, matches partially, or perhaps not at all, which provides data to refine the simulation, but also helps to reconsider how observations were previously interpreted.