• 0 Posts
  • 169 Comments
Joined 1 year ago
cake
Cake day: July 20th, 2023

help-circle









  • https://www.planetary.org/articles/why-international-space-station-cant-operate-forever

    The ISS has gone through multiple reboosts to gain altitude because there is a small amount of atmospheric drag in its orbit. That’s not the limiting factor though.

    The structure is aluminum. Aluminum accumulates fatigue damage every time it flexes. Every time the iss goes from sunlight to the earths shadow, there is significant thermal expansion/contraction. This fatigues the structure. The repeated docking maneuvers also stress the structure. Radiation and atomic oxygen also cause degredation. All those factors are relatively minor in any given year, but are always accumulating. The ISS is getting less safe and the risk of a structural failure is increasing.

    On top of that all, a bunch of the systems on board were designed 30 years ago. There have been major changes in communications, power systems, etc. in the time since the modules were built. Even though new experiments are built all the time, they are still constrained by capabilities of the capsules they operate in. So there are also science advantages to moving to a newer platform.




  • That depends on your client. Connect for lemmy shows a placeholder for comments from blocked instances. You can click to show the comment anyway or just blissfully ignore the high probability rage bait.

    I actually like that implementation, because the obnoxiousness of hexbear users is context dependent. On posts about gardening and nolawns I’ll usually see what they have to say. On political posts, I usually regret reading their comments. So it’s somewhat nice to opt-in to comments on a case by case basis.





  • Fermion@feddit.nltoScience Memes@mander.xyz😳😳😳
    link
    fedilink
    English
    arrow-up
    39
    arrow-down
    1
    ·
    edit-2
    22 days ago

    There’s no danger for an mri unless you’ve had major surgery involving metal inplants. There’s no ionizing radiation so there should be no risks for the fetus.

    Cost and scarcity are big limiting factors for mri though. Mri machines are massive permanent installations that cost in the millions. They are already busy with people who need diagnostics of specific conditions. Putting every expectant mother in one would lead to absurd wait times. Whereas doctors offices can have multiple little ultrasound machines on carts that are easy to quickly acquire imagining as part of routine visits.