How Different Are SpaceX Thermal Tiles From The Space Shuttle’s?

February 14, 2024 by Maya Posch 9 Comments

When SpaceX first showed off the thermal tiles on its Starship spacecraft that should keep it safe when re-entering the Earth’s atmosphere towards the loving embrace of the chopsticks on the launch tower, some similarity to the thermal tiles on NASA’s now retired Space Shuttle Orbiter was hard to miss.

Electron microscope image of the fibrous part of a Starship thermal tile, showing very large fibers. (Credit: Breaking Taps, YouTube)

Yet how similar are they really? That’s what the [Breaking Taps] channel on YouTube sought to find out, using an eBay-purchased chunk of Shuttle thermal tile along with bits of Starship tiles that washed ashore following the explosive end to the vehicle’s first integrated test last year.

To answer the basic question: the SpaceX engineers responsible for the Starship thermal tiles seem to have done their homework. An analysis of not only the structure of the fibrous material, but also the black IR-blocking coating, shows that the Starship tiles are highly reminiscent of the EATB (introduced in 1996) tiles with TUFI (toughened unipiece fibrous insulation) coatings with added molybdenum disilicide, which were used during the last years of the Shuttle program.

TUFI is less fragile than the older RCG (reaction cured glass) coating, but also heavier, which is why few TUFI tiles were used on the Shuttles due to weight concerns. An oddity with the Starship tiles is that they incorporate many very large fibers, which could be by design, or indicative of something else.

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An image of a cave drawing of horned cow. There is another one coming up behind it as well. There are four dots as described by the researchers on the main cow's back.

Writing – So Easy A Caveperson Could Do It

February 13, 2024 by Navarre Bartz 10 Comments

We modern humans tend to take writing for granted, and often forget that like any other technology, somebody had to invent it. Researchers from Cambridge believe they’ve determined the purpose of one of the earliest writing beta-tests.

Examining a database of images taken in caves throughout Europe and dated to the Upper Paleolithic, the researchers found “three of the most frequently occurring signs—the line <|>, the dot <•>, and the <Y>—functioned as units of communication.”

It appears the <|> and <.> symbols when “in close association with images of animals” denote time relating to lunar months of the year, starting with spring as the new year. The <Y> symbol appears to carry the meaning <To Give Birth> allowing early people a way to tell others information about the prey of a region, which would be pretty handy when hunting and gathering are your only options for food.

We’ve covered other ancient technologies like storytelling and abrasives. If you’re curious what the climate was like for our ancestors, perhaps paleoclimatology will tickle your fancy.

3D Printing Functional Human Brain Tissue For Research Purposes

February 12, 2024 by Maya Posch 18 Comments

Graphical summary of the newly developed 3D bioprinting process. (Credit: Yan et al., 2024)

The brain is probably the least explored organ, much of which is due to the difficulty of studying it in situ rather than in slices under a microscope. Even growing small organoids out of neurons provide few clues, as this is not how brain tissue is normally organized. A possible breakthrough may have been found here by a group of researchers whose article in Cell Stem Cell details how they created functional human neural tissues using a commercial 3D bioprinter.

As detailed by [Yuanwei Yan] and colleagues in their research article, the issue with previous approaches was that although these would print layers of neurons, they would fail to integrate as in the brain. In the brain’s tissues, we see a wide variety of neurons and supportive cells, all of which integrate in a specific way to form functioning neuron-to-neuron and neuron-to-glial connections with expected neural activity. The accomplishment of this research team is 3D bioprinting of neural tissues with the necessary functional connections.

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AI’s Existence Is All It Takes To Be Accused Of Being One

February 11, 2024 by Donald Papp 31 Comments

New technologies bring with them the threat of change. AI tools are one of the latest such developments. But as is often the case, when technological threats show up, they end up looking awfully human.

Recently, [E. M. Wolkovich] submitted a scientific paper for review that — to her surprise — was declared “obviously” the work of ChatGPT. No part of that was true. Like most people, [E. M. Wolkovich] finds writing a somewhat difficult process. Her paper represents a lot of time and effort. But despite zero evidence, this casual accusation of fraud in a scientific context was just sort of… accepted.

There are several reasons this is concerning. One is that, in principle, the scientific community wouldn’t dream of leveling an accusation of fraud like data manipulation without evidence. But a reviewer had no qualms about casually claiming [Wolkovich]’s writing wasn’t hers, effectively calling her a liar. Worse, at the editorial level, this baseless accusation was accepted and passed along with vague agreement instead of any sort of pushback.

Showing Your Work Isn’t Enough

Interestingly, [Wolkovich] writes everything in plain text using the LaTeX typesetting system, hosted on GitHub, complete with change commits. That means she could easily show her entire change history, from outline to finished manuscript, which should be enough to convince just about anyone that she isn’t a chatbot.

But pondering this raises a very good question: is [Wolkovich] having to prove she isn’t a chatbot a desirable outcome of this situation? We don’t think it is, nor is this an idle question. We’ve seen how even when an artist can present their full workflow to prove an AI didn’t make their art, enough doubt is sown by the accusation to poison the proceedings (not to mention greatly demoralizing the creator in the process.)

Better Standards Would Help

[Wolkovich] uses this opportunity to reflect on and share what this situation indicates about useful change. Now that AI tools exist, guidelines that acknowledge them should be created. Explicit standards about when and how AI tools can be used in the writing process, how those tools should be acknowledged if used, and a process to handle accusations of misuse would all be positive changes.

Because as it stands, it’s hard to see [Wolkovich]’s experience as anything other than an illustration of how a scientific community’s submission and review process was corrupted not by undeclared or thoughtless use of AI but by the simple fact that such tools exist. This seems like both a problem that will only get worse with time (right now, it is fairly easy to detect chatbots) and one that will not solve itself.

NIF’s Laser Fusion Experiment’s Energy Gain Passes Peer Review

February 9, 2024 by Maya Posch 53 Comments

Back in December of 2022, a team of researchers at the USA’s National Ignition Facility (NIF) announced that they had exceeded ‘scientific breakeven’ with their laser-based inertial confinement fusion (ICF) system. Their work has now been peer-reviewed and passed scrutiny, confirming that the energy put into fusing a small amount of deuterium-tritium fuel resulted in a net gain (Q) of 1.5.

Laser Bay 2, one of NIF's two laser bays — Laser Bay 2 at the NIF.

The key take-away here of course remains that ICF is not a viable method of producing energy, as we detailed back in 2021 when we covered the 1.3 MJ yield announcement, and again in 2022 following the subject of this now completed peer review. The sheer amount of energy required to produce the laser energy targeting the fuel capsule and loss therein, as well as the energy required to manufacture each of these fuel capsules (Hohlraum) and sustaining a cycle make it a highly impractical proposition for anything except weapons research.

Despite this, it’s good to see that the NIF’s ICF research is bearing fruit, even if for energy production we should look towards magnetic confinement fusion (MCF), which includes the many tokamaks active today like Japan’s JT-60SE, as well as stellarators like Germany’s Wendelstein 7-X and other efforts to make MCF a major clean-energy source for the future.

A schematic representation of the different ionospheric sub-layers and how they evolve daily from day to night periods. (Credit: Carlos Molina)

Will Large Satellite Constellations Affect Earth’s Magnetic Field?

February 7, 2024 by Maya Posch 48 Comments

Imagine taking a significant amount of metals and other materials out of the Earth’s crust and scattering it into the atmosphere from space. This is effectively what we have been doing ever since the beginning of the Space Age, with an increasing number of rocket stages, satellites and related objects ending their existence as they burn up in the Earth’s atmosphere. Yet rather than vanish into nothing, the debris of this destruction remains partially in the atmosphere, where it forms pockets of material. As this material is often conductive, it will likely affect the Earth’s magnetic field, as argued by [Sierra Solter-Hunt] in a pre-publication article.

A summary by [Dr. Tony Phillips] references a 2023 NASA research article by [Daniel M. Murphy] et al. which describes the discovery that about 10% of the aerosol particles in the stratosphere are aluminium and other metals whose origin can be traced back to the ‘burn-up’ of the aforementioned space objects. This is a factor which can increase the Debye length of the ionosphere. What the exact effects of this may be is still largely unknown, but fact remains that we are launching massively more objects into space than even a decade ago, with the number of LEO objects consequently increasing.

Although the speculation by [Sierra] can be called ‘alarmist’, the research question of what’ll happen if over the coming years we’ll have daily Starlink and other satellites disintegrating in the atmosphere is a valid one. As this looks like it will coat the stratosphere and ionosphere in particular with metal aerosols at levels never seen before, it might be worth it to do the research up-front, rather than wait until we see something odd happening.

Metal Crystal Stops Electrons

February 7, 2024 by Al Williams 14 Comments

Researchers at Rice University have found an alloy of copper, vanadium, and sulfur that forms crystals that, due to quantum effects, can trap electrons. This can produce flat bands, which have been observed in 2D crystals previously. The team’s results are the first case of a 3D crystal with that property.

The flat band term refers to the electron energy bands. Normally, the electrons change energy levels based on momentum. But in a flat band, this doesn’t occur. This implies that the electrons are nearly stationary, which leads to unique optical, electronic, and magnetic properties. In addition, flat-band materials often exhibit unusual behavior, such as exotic quantum states, ferromagnetism, or even superconductivity.

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