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Cake day: June 18th, 2023

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  • mkwt@lemmy.worldtoScience Memes@mander.xyzLand where
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    1 day ago

    The capsules can do a water splashdown with parachutes alone.

    The capsules that land on land all seem to have some additional system to slow down in addition to the parachute. Boeing Starliner has airbags that deploy around and below the heat shield. Soyuz has a braking rocket system that fires immediately before impact.



  • It was a three-barreled gun that fired shotgun shells, rifle rounds, and rescue flares. 10 rounds of each type of ammunition were supplied. The stock could be detached and used as a machete.

    For a while, these guns were on every Soyuz capsule that docked with ISS, and they were under the operational control of the Soyuz commander. I’ve read that they may have been retired in 2007 because Russia finally ran out of the very unique ammo.


  • They later said it was less than 1 mile away from the target spot.

    A big benefit of the ocean is if the capsule loses all attitude control, it can still reenter and survive. But it will be a “ballistic reentry”, much more punishing with the g forces, and also about 1500 miles short of the target zone.

    The Pacific Ocean makes it easy to ensure that those backup contingency landing sites are also safe landing sites.


  • The Russian system has a braking rocket that fires at the very last second to soften up the landing. On one early Soyuz mission, this rocket didn’t fire, and the solo cosmonaut suffered substantial injuries from the landing.

    The Orion capsule hits the water at the final parachute speed of 20-30 mph without injuring the crew. But as you state, they also have to design the capsule for flotation and egress in potentially rough sea state.

    Boeing Starliner is designed for a land landing, but it uses deployable air bags instead of a braking rocket. It’s not clear that Starliner will ever fly again after the RCS thruster problems.





  • I believe two of these are naval aviators, and they would take exception with the “army” characterization.

    But you’re generally correct. It’s very common that astronauts will not only have a military background, they frequently are active duty military officers on a long term detail to NASA.

    The army is not well represented in the astronaut corps, because the US army only flies helicopters under an inter-branch coordination agreement.


  • Toilet drains into two different containers for each type of waste. The urine holding tank periodically vents overboard. The feces canisters are stored and returned to earth.

    The ongoing problem is that the urine holding tank is not venting into space very well when they open the valve. The toilet drains both waste types into their containers ok. But since the urine holding tank is about the size of an office trash can, it can fill up very fast.



  • If you’re training right it never gets any easier, but you do get faster.

    Having said that, most people when they first start can’t run slow enough to maintain a stable aerobic heart rate. The solution is alternating run / walk, building up to progressively more running between walk breaks.

    As an example, right now I can maintain 11:00 mi / mile at, my threshold heart rate, where I can maintain a conversation, and feel like I can keep going indefinitely. So I run 80% of my runs at that speed, and the rest at faster speeds over shorter distances. Great.

    But 2 years ago when I restarted running after a break, my aerobic pace was more than 13:00 / mile. That’s a problem because at that speed I can’t physically maintain the running mechanic. It breaks down. So the only options are to run faster than optimal, which means you’re not getting aerobic training (instead it’s anaerobic training); or to slow down into the walking mechanic.

    Research suggests that slow running in the aerobic zone is the key to improving aerobic pace and endurance. And if that aerobic pace is not possible because of mechanics, then alternating run / walk is a good way to average out the heart rate.




  • Just to be clear: with a marginal tax rate, if your income is $10,000,001, you pay $0.70 tax for the $1, and the rest of the $10,000,000 is taxed according to the lower tax brackets.

    The first $50,000 of that $10 million is taxed just like the guy that only made $50,000.

    The US tax system is slightly more complicated than this, but there’s no situation where you can get stuck with a huge additional bill because you edged slightly into the next higher tax bracket.