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Cake day: July 31st, 2023

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  • 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.






  • I’m not sure becoming desensitised to trauma is an effective strategy either. That suggests that we stop caring about what’s going on.
    I’m in the same situation, 2016-2020 was a stressful time. Constantly trying to keep up with each horrible new development, about which I could do nothing but despair, became an unhealthy obsession. I don’t want to do that again. I’m not a political scientist, and I neglected my own personal growth and development becoming an armchair expert in politics because I could see what was happening. This time I’m going to focus on myself and the people around me because that’s all I can do. The world will keep turning. If I have the opportunity to do something positive, I’ll take it.






  • Does he?

    Does he what?

    He clearly supported Brexit no matter what the semantics of it are

    What do you mean by the word “semantics” in this sentence? I don’t think it means what you think it means.
    Here are some examples of John Oliver opposing Brexit:

    guardian, 2019

    Last Week Tonight, Jun 2016

    Last Week Tonight, Brexit ii

    Last Week Tonight, Brexit iii

    John Oliver publicly, repeatedly opposed Brexit, using his considerable platform to do so. With respect, you are talking out of your anus.

    You seem to want to paint John Oliver as a stereotype, and then claim that this is all he is. I find that reductive, ignorant and distasteful. Here is someone who addresses issues varying from presidential accountability to gambling laws, national, international and global issues, with compassion, logic, humanity and humour. And you try to boil him down to a stereotype. You’re not even able to define the stereotype you’re trying to invoke. It would be funny if it weren’t shameful.







  • Your comment doesn’t stand up. It seems you’ve got something against fusion energy for some reason.
    On cost: it’s a best guess, since we don’t yet have a working fusion reactor. The error bars on the cost estimates are huge, so while it is possible fusion will be more expensive, with current data you absolutely cannot guarantee it. Add to that the decreasing costs as the technology matures, like we’ve seen in wind and especially solar over recent decades.
    On nuclear physics PhDs: that’s no different to any energy generation, you need dozens of experts to build and run any installation.
    On waste: where are you getting this info on the blanket? The old beryllium blanket design has been replaced with tungsten and no longer needs to be replaced. The next step is to test a lithium blanket which will actually generate nuclear fuel as the reaction processes.
    This is the important fact that you have omitted, for some reason.

    Nuclear fusion reactors produce no high activity, long-lived nuclear waste. The activation of components in a fusion reactor is low enough for the materials to be recycled or reused within 100 years

    And that is why it’s so important this technology is developed. It’s incredibly clean and, yes, limitless.

    As for your advice, there was a time not long ago when we didn’t understand how to build fission plants either, and it cost a lot of time and money to learn how. I wonder if people back then were saying we should just stick to burning coal because we know how that works.