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Do not attempt to compete with Pinboard. http://pinboard.in  maciej@ceglowski.com +1 415 610 0231

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    1. Robotbeat 🗽 ➐‏ @Robotbeat Oct 17
      Replying to @Pinboard @dingir_bhaak

      I’m sure you’ll ignore this, but: For a transit time of 3-4 months, that’s a solved problem. The Russians had a >400 day mission and the dude who did it walked after landing on Earth. That’s 3 times the gravity of Mars and 4 times the duration of Mars transit on Starship.

      2 replies 1 retweet 5 likes
    2. Pinboard‏ @Pinboard Oct 18
      Replying to @Robotbeat @dingir_bhaak

      Cosmic ray radiation levels in low earth orbit are 2-4x lower than in a Mars transit, and a Mars transit would take six months, not 3-4.

      1 reply 0 retweets 0 likes
    3. Robotbeat 🗽 ➐‏ @Robotbeat Oct 18
      Replying to @Pinboard @dingir_bhaak

      Wrong. The trip time is a function of the rocket architecture, you know the part you think is just the fun part that isn’t the REAL issue. ;) SpaceX’s ITS/BFR/Starship would take as few as 80 days to transit, depending on the year. https://www.spacex.com/media/making_life_multiplanetary_2016.pdf …pic.twitter.com/oiAIp3EIus

      1 reply 1 retweet 8 likes
    4. Pinboard‏ @Pinboard Oct 18
      Replying to @Robotbeat @dingir_bhaak

      I go by the NASA design reference architecture because Musk has a very long history of making shit up.

      1 reply 0 retweets 0 likes
    5. Robotbeat 🗽 ➐‏ @Robotbeat Oct 18
      Replying to @Pinboard @dingir_bhaak

      Oh, okay, good to know you think SpaceX, who is the only US company NASA trusts to launch humans to orbit right now, just makes stuff up & is ignoring radiation (versus addressing it with the perfectly valid method of using more fuel and aero braking to do a faster transit time).pic.twitter.com/muvofQA6ED

      2 replies 0 retweets 12 likes
    6. Pinboard‏ @Pinboard Oct 18
      Replying to @Robotbeat @dingir_bhaak

      I think it's silly to argue about transit times for a rocket that doesn't exist. Until it does, I'm using the reference plans from the one group that has landed humans on another celestial body.

      3 replies 0 retweets 0 likes
    7. Casey Handmer, PhD‏ @CJHandmer Oct 18
      Replying to @Pinboard @Robotbeat @dingir_bhaak

      This is the same orbital dynamics anyone has to deal with. 4-6 months is very doable. Regarding radiation, if only someone had written a blog on it...pic.twitter.com/o5TvpmCHza

      2 replies 0 retweets 8 likes
    8. Casey Handmer, PhD‏ @CJHandmer Oct 18
      Replying to @CJHandmer @Pinboard and

      https://caseyhandmer.wordpress.com/2019/10/20/omg-space-is-full-of-radiation-and-why-im-not-worried/ …

      2 replies 1 retweet 11 likes
    9. Pinboard‏ @Pinboard Oct 18
      Replying to @CJHandmer @Robotbeat @dingir_bhaak

      The specific issue threatening Mars missions is how bone injury from deep-space radiation couples with bone loss from microgravity. They are different mechanisms and we simply don't know how they interact.

      2 replies 0 retweets 0 likes
    10. Robotbeat 🗽 ➐‏ @Robotbeat Oct 18
      Replying to @Pinboard @CJHandmer @dingir_bhaak

      We’ve done super long trips in LEO which have both microgravity & radiation. The radiation (which includes some trapped radiation, BTW) was half as intense but trips lasted well over twice as long as transit. We’ve got some idea now. It’s simply no longer a complete question mark

      2 replies 0 retweets 1 like
      Pinboard‏ @Pinboard Oct 18
      Replying to @Robotbeat @CJHandmer @dingir_bhaak

      You have this wrong; GCR radiation dose is four times as intense on a trip to Mars as it is over an equivalent period on ISS, and includes cosmic rays at lower energies that don't reach LEO.

      12:08 PM - 18 Oct 2021
      1 reply 0 retweets 0 likes
        1. New conversation
        2. Robotbeat 🗽 ➐‏ @Robotbeat Oct 18
          Replying to @Pinboard @CJHandmer @dingir_bhaak

          Right. And ISS includes a bunch of trapped radiation from the lower part of the Van Allen belts (the South Atlantic Anomaly) which isn’t present in deep space. To account for different effects on tissue, we adjust by the Quality Factor. That’s already included in the Sievert unit

          1 reply 0 retweets 2 likes
        3. Pinboard‏ @Pinboard Oct 18
          Replying to @Robotbeat @CJHandmer @dingir_bhaak

          And the Mars transit exposure for this radiation in Sieverts, with all fudge factors applied, is over four times that of ISS

          1 reply 0 retweets 0 likes
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