TFINER is an Atompunk Solar Sail Lookalike
It’s not every day we hear of a new space propulsion method. Even rarer to hear of one that actually seems halfway practical. Yet that’s what we have in the case of TFINER, a proposal by [James A. Bickford] we found summarized on Centauri Dreams by [Paul Gilster] .
TFINER stands for Thin-Film Nuclear Engine Rocket Engine, and it’s a hoot. The word “rocket” is in the name, so you know there’s got to be some reaction mass, but this thing looks more like a solar sail. The secret is that the “sail” is the rocket: as the name implies, it hosts a thin film of nuclear materialwhose decay products provide the reaction mass. (In the Phase I study for NASA’s Innovative Advanced Concepts office (NIAC), it’s alpha particles from Thorium-228 or Radium-228.) Alpha particles go pretty quick (about 5% c for these isotopes), so the ISP on this thing is amazing. (1.81 million seconds!)
Now you might be thinking, “nuclear decay is isotropic! The sail will thrust equally in both directions and go nowhere!”– which would be true, if the sail was made of Thorium or Radium. It’s not; the radioisotope is a 9.5 um thin film on a 35 um beryllium back-plane that’s going to absorb any alpha emissions going the wrong way around. 9.5um is thin enough that most of the alphas from the initial isotope and its decay products (lets not forget that most of this decay chain are alpha emitters — 5 in total for both Th and Ra) aimed roughly normal to the surface will make it out.
Since the payload is behind the sail, it’s going to need a touch of shielding or rather long shrouds; the reference design calls for 400 m cables. Playing out or reeling in the cables would allow for some degree of thrust-vectoring, but this thing isn’t going to turn on a dime.
It’s also not going to have oodles of thrust, but the small thrust it does produce is continuous, and will add up to large deltaV over time. After a few years, the thrust is going to fall off (the half-life of Th-228 is 1.91 years, or 5.74 for Ra-228; either way the decay products are too short-lived to matter) but [Bickford]’s paper gives terminal/cruising velocity in either case of ~100 km/s.
Sure, that’s not fast enough to be convenient to measure as a fraction of the speed of light, and maybe it’s not great for a quick trip to Alpha Centauri but that’s plenty fast enough for to reach the furthest reaches of our solar system. For a flyby, anyway: like a solid-fueled rocket, once your burn is done, it’s done. Stopping isn’t really on offer here. The proposal references extra-solar comets like Oumuamua as potential flyby targets. That, and the focus of the Sun’s gravitational lens effect. Said focus is fortunately not a point, but a line, so no worries about a “blink and you miss it” fast-flyby. You can imagine we love both of those ideas.
NASA must have too, since NIAC was interested enough to advance this concept to a Phase II study. As reported at Centauri Dreams, the Phase II study will involve some actual hardware, albeit a ~1 square centimeter demonstrator rather than anything that will fly. We look forward to it. Future work also apparently includes the idea of combining the TFINER concept with an actual solar sail to get maximum possible delta-V from an Oberth-effect sundive. We really look forward to that one.
New Zealand Rugby Players Face Higher Dementia Risk, Study Finds
https://www.bloomberg.com/news/articles/2025-09-05/elite-new-zealand-rugby-players-more-likely-to-develop-dementia-study-finds?utm_source=flipboard&utm_medium=activitypub
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Chuck Todd Spells Out Why RFK Jr. Is Posing The 'Biggest Problem' For Trump
https://www.huffpost.com/entry/chuck-todd-trump-rfk-jr-senate-hearing_n_68ba2464e4b04dd23504322e?utm_source=flipboard&utm_medium=activitypub
Posted into News & Politics @news-politics-huffingtonpost
Chuck Todd Spells Out Why RFK Jr. Is Posing The 'Biggest Problem' For Trump
The former "Meet the Press" host said he expects the president will eventually throw his health secretary "overboard."Ben Blanchet (HuffPost)
Antenna ad Antraccoli, è ancora polemica. Bianucci: “Sbaglio da evitare”
Il consigliere comunale di Sinistra Con, Daniele Bianucci, si unisce all'appello dell'Osservatorio Permanente sulla Telefonia Mobile del Comune di Lucca sulla revoca dell'autorizzazione per l'installazione del nuovo ripetitore collocato nel campo di fronte all'incrocio tra via Romana e via dei Pini.
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Antenna ad Antraccoli, è ancora polemica. Bianucci: "Sbaglio da evitare" - NoiTV
Il consigliere comunale di Sinistra Con, Daniele Bianucci, si unisce all'appello dell'Osservatorio Permanente sulla Telefonia Mobile del Comune di Lucca sulla revoca dell'autorizzazione per l'installazione del nuovo ripetitore collocato nel campo di …Redazione NoiTV (NoiTV)
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schlagloch: Die Ansichtskarten wurden hinter… schlagloch.at/2025/09/04/die-a…
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Die Ansichtskarten wurden hinter… | Schlagloch
...die Schmuckleiste der Küchenkredenz gesteckt. Ob es heute möglich ist eine Kutschenfahrt mit der Kreditkarte zu bezahlen oder nur Bargeld angenommen wird, habe ich nicht erfahren.schlagloch (Schlagloch)
Cook Says Harvard Funding Fight Shows Trump’s Hidden Motives
https://www.bloomberg.com/news/articles/2025-09-05/cook-says-harvard-funding-fight-shows-trump-s-hidden-motives?utm_source=flipboard&utm_medium=activitypub
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Il caso del "Nutella Sweet & Café" a Gaza. Ecco cosa sappiamo
https://www.open.online/2025/09/05/gaza-nutella-sweet-cafe-cosa-sappiamo-fc/?utm_source=flipboard&utm_medium=activitypub
Pubblicato su ULTIME NEWS @ultime-news-OpenGiornale
Il caso del “Nutella Sweet & Café” a Gaza. Ecco cosa sappiamo
Il locale si trova effettivamente a Gaza e risulta inaugurato da pochi giorniDavid Puente (Open)
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« Le but du jeu n’est absolument pas de restreindre les libertés ou de taper sur l’enseignement supérieur privé, qu’il soit lucratif ou non. Le but du jeu, au contraire, c’est que ces formations et ces établissements se développent » Ph.Piaille
First Brain-Wide Map of Decision-Making Charted In Mice - Slashdot
In a landmark collaboration across 22 labs, neuroscientists have created the first brain-wide map of decision-making in mice, tracking over 620,000 neurons across nearly 280 brain regions.science.slashdot.org
Britain’s universities feel the heat of its migration culture war
https://www.politico.eu/article/britain-international-student-university-tuition-education/?utm_source=flipboard&utm_medium=activitypub
Posted into POLITICO Migration @politico-migration-POLITICOEurope
Britain’s universities feel the heat of its migration culture war
Governments of all stripes have nudged overseas brainiacs away from U.K. universities. Those educational establishments are now feeling the pinch.Noah Keate (POLITICO)
Farage treads a fine line as anti-migrant protests rage
https://www.politico.eu/article/nigel-farage-anti-migrant-britain-asylum-seekers-reform-uk/?utm_source=flipboard&utm_medium=activitypub
Posted into POLITICO Migration @politico-migration-POLITICOEurope
Farage treads a fine line as anti-migrant protests rage
Farage’s support base is growing. Can he keep moderate voters while pleasing the further reaches of the right?Caroline Hug (POLITICO)
Unfortunately, a decay ended up developing underneath and it had to be replaced a few months ago.
Russia-Ukraine war: List of key events, day 1,289
https://www.aljazeera.com/news/2025/9/5/russia-ukraine-war-list-of-key-events-day-1289?utm_source=flipboard&utm_medium=activitypub
Posted into Europe News @europe-news-AlJazeera
Russia-Ukraine war: List of key events, day 1,289
Here are the key events on day 1,289 of Russia’s war on Ukraine.Al Jazeera
pftnhr.xyz: UberBlogr - Mehr Webring ist grundsätzlich nicht nötig pftnhr.xyz/ich-hab-vor-knapp-z…
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UberBlogr - Mehr Webring ist grundsätzlich nicht nötig
Ich hab vor knapp zwei Jahren begonnen an einem eigenen Webring zu basteln, doch limitierte Fähigkeiten ließen das ganze Unterfangen unendlich zäh…pftnhr.xyz
Francia: il 10 settembre blocchiamo tutto, atteso il voto di fiducia per Bayrou
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Da circa un mese sui social e sui siti di movimento, ma non solo, è iniziato a girare un appello per una giornata di mobilitazione e di blocco per il 10 settembre. In questa giornata infatti, in tutto l’esagono si...
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🌞 Hello #fediverse! This is GBH #News bringing you the world from #Boston. It's 74F at Logan Airport and visibility is 10mi.
Officials say a lockdown at UMass Lowell that lasted hours yesterday was in response to a youth with a realistic-looking Airsoft gun.
HHS Secretary Robert F. Kennedy faced questioning by Congress today about turmoil at the CDC.
A federal judge reversed billions of dollars in research funding cuts to Harvard yesterday.
Made a post about regulating my nervous system and getting better with somatic stuff RE my cPTSD. It's had a pretty big impact on my IBS!
thinkymeat.neocities.org/posts… #cPTSD #blog #autism #trauma
—> #MSNBC ⦁ All In ⦁ #ChrisHayes <— #MTG, #Boebert, #Mace to back #EpsteinFiles #Vote, DEFYING #Trump #WhiteHouse#Epstein#Pol #Politics #GeoPolitics #WorldNews #News#AusPol #CdnPoli #EUpol #NZpol #UKpol #USpolyoutu.be/Q2Y4twRsyOg
Chinese firms still want Nvidia chips despite Beijing pressure not to buy, sources say
Alibaba, ByteDance and others are eager to buy Nvidia’s H20 and Blackwell-based B30A processors, people familiar with the matter say.Reuters (South China Morning Post)
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“Reply: it’s not my fault you suck compared to bunnies.”
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The image contains a text message presented in a plain white background with black text. The text is structured in a block format, with each sentence on a new line. The message discusses the biological differences between men and women in terms of reproduction, specifically focusing on the number of pregnancies a woman can have compared to a man. It concludes with a rhetorical question about the regulation of women. The text is straightforward and does not include any images or additional design elements.
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CPMI do INSS marca depoimentos do “Careca do INSS” e de empresário alvo da PF - Gazeta Brasil- Notícias do
A CPMI do INSS, presidida por Carlos Viana, segue concentrando esforços para rastrear as movimentações e conexões dos suspeitos dentro e fora do Congresso.Gazeta Brasil
¡Sabor a política! 🌶️ La nota "Aguachile Bartlett" le da a septiembre un toque diferente. Conoce esta original perspectiva que fusiona gastronomía y política en la nota. #AguachileBartlett #Gastronomía #Política #Septiembre
Más aquí: zurl.co/9H1EU
Aguachile Bartlett: septiembre con un toque diferente
Septiembre es el mes de México, un tiempo para celebrar nuestra cultura y tradiciones a través de los sabores que nos representan: desde los emblemáticos chiles en nogada hasta el reconfortante pozole.Periodistas Unidos
Attaque israélienne à Sanaa : quelles conséquences pour la région ?
« Pourquoi cette attaque maintenant, et quelles en seront les conséquences possibles pour le #MoyenOrient ?
Nous en avons discuté avec Elisabeth Kendall, présidente du Girton College de l’université de Cambridge. »
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#Yémen #mouvementHouthiste #Israël #AxeDeLaRésistance #Gaza @yemen @israel @palestine
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Nelle famiglie benestanti le donne guadagnano il 25% in meno degli uomini
https://www.agi.it/scienza/news/2025-09-05/divario-retributivo-genere-regno-unito-33007560/?utm_source=flipboard&utm_medium=activitypub
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