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Cake day: June 15th, 2023

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  • Python’s public API changes subtly, so minor changes in Python version can lead to massive changes in the version of dependencies you use.

    A few years ago we developed a script to update Cassandra on Python 2.7.Y. Production environment used Python 2.7.X (it was 5 patch releases earlier).

    This completely changed the cassandra library version. We had to go back 15 patch releases which annoying resulting in a breaking change in the Cassandra libraries API and wouldn’t work on the dev environments Python.

    Python 3 hasn’t solved this, 2 years ago I was asked to look at a number of Machine Learning projects running in docker. Upgrading Python from 3.4 to 3.8 had a huge effect on dependencies and figuring out the right combination was a huge pain.

    This is a solved problem in Java, Node.js has the same weakness but their changes to language spec are additive so old code runs on new releases (just not the inverse). Ruby has exactly the same issues as Python



  • If you read the reports…

    Normally JPL outsource their Mars mission hardware to Lockheed Martin. For some reason they have decided to do Mars Sample Return in house. The reports argue JPL hasn’t built the necessary in house experience and should have worked with LM.

    Secondly JPL is suffering a staff shortage which is affecting other projects and the Mars Sample Return is making the problem worse.

    Lastly if an organisation stops performing an action it “forgets” how to do it. You can rebuild the capability but it takes time.

    A team arbitrary declaring they are experts and suddenly decideding they will do it is one that will have to relearn skills/knowledge on a big expensive high profile project. The project will either fail (and be declared a success) or masses of money will be spent to compensate for the teams learning.

    Either situation is not ideal


  • I have always had 1 question.

    In voyager we see the Borg have thousands of ships of varying sizes and control a vast area of space. Voyager is able to take down spheres and small cubes.

    Yet in Wolf 359 a single cube attacks and destroys hundreds of star fleet vessels. If a single cube is able to have that level of effect why didn’t the borg commit a larger fleet?

    You have the same issue in First Contact, they only commit 1 cube.

    Considering how difficult the federation finds holding them back, attacking with 3-6 cubes would seemto assure victory


  • The GAO has performed an annual review of the Space Launch System every year since 2014 and switched to reviewing the Artemis program in 2019.

    Each year the GAO points out Nasa isn’t tracking any costs and Nasa argues with the GAO about the costs they assign. Then the GAO points out Nasa has no concrete plan to reduce costs, Nasa then goes nu’uh (see the articles cost reduction “objectives”).

    The last two reports have focused on the RS-25 engine, last time the GAO was unhappy because an engine cost Nasa $100 million and Nasa had just granted a development contract to reduce the cost of the engine.

    However if you took the headline cost of the contract and split it over planned engines it was greater than the desired cost savings. Nasa response was development costs don’t count.

    Congress reviews GAO reports and decides to give SLS more money.


  • Similar to most navies.

    Engineering’s workload won’t really change, they’ll do certain types of maintenance.

    Most navies don’t have command staff on the bridge full time. There would be a watch officer who is fairly junior learning how to operate the ship so the down time is an opportunity for them to grow and learn.

    Most navies seperate the captain and first officer, with the first officer involved in running the ship and the captain running the big picture.

    So you would expect the first officer to spend the time checking on every department to ensure they are up to standard.

    That would mean department heads would be running drills or bringing equipment down for maintenance so its ready.

    The captain would likely be planning and thinking through the encounter.

    For any free time senior officers have there is probably a mountain of reports (personnel, ship, intelligence, etc…) to read and keep tabs on.


  • The other person was just wrong.

    Large scale Hydrogen generation isn’t generated in a fossil free way, Hydrogen can be generated is a green way but the infrastructure isn’t there to support SLS.

    Hydrogen is high ISP (miles per gallon) by rubbish thrust (engine torque).

    This means SLS only works with Solid Rocket Boosters, these are highly toxic and release green house contributing material into the upper atmosphere. I suspect you would find Falcon 9/Starship are less polluting as a result.

    Lastly the person implies SLS could be fueled by space sources (e.g. the moon).

    SLS is a 2.5 stage rocket, the boosters are ditched in Earths Atmosphere and the first stage ditched at the edge of space. The current second stage doesn’t quite make low earth orbit.

    So someone would have to mine materials on the moon and ship them back. This would be far more expensive than producing hydrogen on Earth.

    Hydrogen on the moon makes sense if your in lunar orbit, not from Earth.