• yesman@lemmy.world
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    1 day ago

    This is crazy. The Artemis II had to get fast enough to escape our gravity, flew to the moon, did a Tokyo drift around the moon gaining speed the whole time.

    There are few good options to slow down in space, and the plan is to hit the brakes by slamming into the Earth’s atmosphere at a speed that so far outside human experience that the numbers don’t make sense.

    Re-entry is actually the craziest, and most dangerous part of this mission.

    I don’t want to be pessimistic, but I’m a Challenger-kid and this whole business gives me anxiety.

    • Hexagon@feddit.it
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      1 day ago

      Right, except they weren’t “gaining speed the whole time”. They just kept the speed they had at the end of the last engine burn. Which is still a lot of speed

      • Jajcus@sh.itjust.works
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        1 day ago

        They kept the energy, together kinetic (related to they speed) and potential (related to their position). They actual speed/velocity has been changing all the time as the energy has been exchanged one for the other.

    • disorderly@lemmy.world
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      1 day ago

      TIL that objects re-entering the atmosphere vary considerably in their initial velocities, and that ones from further out (e.g. lunar visits) tend to be much faster than those from LEO. It’s not intuitively surprising, but I’d assumed that given the “narrow window” used for re-entry, all objects needed to dump enough velocity to arrive in a fairly tight band.

      • anomnom@sh.itjust.works
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        7 hours ago

        Not nearly as many elementary school kids were watching it live on TV though.

        Columbia was also a preventable tragedy though. And yeah worse for the astronauts, who probably had more awareness of it happening.