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Cake day: July 31st, 2023

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  • Peer pressure is real. Kids get social media accounts way too early because it’s difficult to justify holding off when all of their classmates have them. It causes actual social issues for kids when they are the only one without something. They get bullied etc, so parents are effectively forced to accede. Making it illegal gives parents a reason to say no, which might slow down the uptake.



  • High radiation, toxic (to us) atmosphere and tidal lock don’t preclude life, though. Besides, we can’t detect such details at those distances.

    If a civilization existed and wanted to be discovered at that range, we could detect their signals. Now I’m not trying to argue that life does exist, I’m arguing that the Fermi paradox still poses an interesting question. So, since we could detect a signal coming from a few hundred to a few thousand nearby planets, why don’t we? Is life rare? Is life quiet? Is there no life? Each of the possible reasons we have zero evidence for extraterrestrial life raises incredibly interesting questions that bear thinking about. Why would life be rare? Why would life be quiet? Why would extraterrestrial life have died out, etc.
    The argument that the Fermi paradox just isn’t interesting is quite frankly bonkers.






  • Don’t forget ESA’s ATV and the NASA RRM for refuelling the ISS. As was the case with launchers for a while, the Europeans and the Americans have beautiful, expensive and awesome solutions, while the Russians just get the job done (often by waiving safety standards)

    Anyway, the ISS is a different beast, it’s in LEO and it didn’t need to be launched in one go, so you can send up heavy equipment and integrate it on-orbit, activities which require Gantt charts so autistic that my eyes bleed when I think about them. Starship-to-Starship refuelling would mean sending a single spacecraft up with all the necessary equipment to do propellant transfer, which is what I was thinking of when I wrote my comment, as you say.



  • I’m a space systems propulsion design engineer by profession. I worked on a project which I will not name that requires on-orbit refuelling. (It’s not this one and I don’t and will never work for Elon Musk).
    The technology for in-orbit refuelling doesn’t exist, and there’s a whole lot of new technology required. Remotely docking is akin to self-driving in complexity; don’t forget to factor in the signal delay if you’re in a lunar or translunar orbit. If you make this a crewed activity only, then the problem becomes one of pneumatics. A pressure system that can reliably contain and transfer pressure up to the levels of spacecraft fuel (around 300 psi for liquid, 3000 for gas) repeatedly, in both directions is very, very heavy. The valves are heavy, the tanks are heavy, the control systems are heavy. Too heavy to be considered viable for spaceflight. Even less so for a mission whose payload is “as much transfer fuel as we can possibly get up there”. A huge amount of innovation has to take place before this can become real. As of 2022, when I last worked on this, none of the technology was even being researched, that is to say it was not even at TRL 3. Typically these things take on the order of a decade or so to get to TRL 9, if they are successful and quick.
    I’m not saying it’s impossible, I’m saying I’ll be fascinated to see which solutions they come up with, and that I’m sceptical that they do have current solutions which are feasible and useful, rather than something like a one-shot refueling subsystem that weighs 250kg and delivers 15 litres of hydrazine.