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Lukaszenko

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Posts posted by Lukaszenko

  1. 3 hours ago, mikegarrison said:

    It doesn't really matter to me, I suppose, but is that "8.5 bar" in gauge pressure or absolute pressure? (The difference is about 1 bar.)

    I don't think it would make sense to report it in absolute. Imagine for example, if it failed at 1 bar, absolute :blink:

  2. On 10/1/2019 at 5:07 PM, tater said:

    I think that SpaceX is open enough to data that they will eventually end up with pure space vehicles, and Earth<---->LEO vehicles.

    Take a variant Starship. Remove all TPS. Remove fins. Jettison the entire fairing. You have a cylinder in space now that still has attitude control, solar power, and can be refilled with other Starships. You have a tug/ferry very much in the spirit of the original NASA STS concept (before shuttle stole the name of what was meant to be a SYSTEM of multiple vehicles). What's the dry mass of Starship minus all that stuff? 75 tons? Less?

    Could Super Heavy make orbit with no usable payload? If so, launch it anyway and you end up with something even better. Subtract the fins and legs, and maybe replace a couple engines with vac variants to optimise.

    You can then take the whole RTLS concept to the next level, where the launch site is low-Earth orbit. I wonder how fast that could get you to Mars?

  3. 22 hours ago, DAL59 said:

    dna is not optimal for space applications though

    Why not?

    Quote

    For data storage density nature currently has us well beaten - 1 gram of perfectly encoded DNA could theoretically store 455 exabytes of data, if you could keep it in a state that was both stable & somehow readable.

    All sources I checked say that "215 petabytes of data in a single gram of DNA" is 85% of the theoretical limit. Where did you find 455 exabytes :o?

  4. 3 hours ago, CatastrophicFailure said:

    Tho, according to Reddit via some random guy on twitter, this will actually be the first "long loiter" mission, the upper stage will fire again at apogee to partially circularize the orbit of the GPS sat, not just send it on a transfer orbit.

    If that's the case, then maybe there IS a good reason for it after all. They'll probably need all the energy they can get.

  5. 14 hours ago, tater said:

    They crashed many times learning how to land, and a couple after learning (FH, and one other, I think). So out of 65 launches, and maybe 40-something landing attempts, they have landed 32.

    I don't think it's fair to count destructive tests during the R&D phase as "failures". Even after the first successes there's a grey zone. 

    Perhaps when they stopped referring to it as "experimental landing" and simply "landing" would be a good starting point to count failures/ successes.

  6. 34 minutes ago, DAL59 said:

    SpaceX doesn't care if some people protest.  Those people aren't their customers.  

    Given how much effort they put into their PR, I'm guessing that they DO care. Maybe those people aren't directly their customers, but they have an influence on the people who are.

  7. 47 minutes ago, Wjolcz said:

    Wouldn't carbon fiber be lighter than kevlar though?

    Does anyone know how kevlar and carbon fiber degrade in space conditions over time?

    Probably, I didn't realize that they made ropes out of the stuff. Makes sense though.

  8. 55 minutes ago, Rus-Evo said:

    I suspect that the weight of cable is a big DV downside.

     

    Based on this link, I estimate a kevlar cable would weigh about 5 kg/m for a 450 ton BFS at 1g. I don't know how much you want, maybe 100 m? So that's 500 kg, and that's probably waaaay over-engineered.

  9. 1 hour ago, NSEP said:

    The BFS pressurized compartement should have stairs/ladders, without a doubt. Remember, the BFS is going to land and stay on Mars for several months or years, and you have to bring the people down and back from their cabins somehow when you are on Mars. The BFS will probably house people, and/or cargo even after the bases have been built, as extra room. If i had a giant spaceship with the internal volume of a big airliner, i wouldn't waste that space on nothing.

    2 hours ago, Wjolcz said:

    Stairs? Why not ladders?

    Yeah, maybe, but it's tall and ladders aren't the safest things. 

    But indeed, it will be on Mars anyway. Perhaps I overanalyzed. Still, if there is a big open common area, having space in 3d would be, well, more space.

  10. 9 hours ago, Ultimate Steve said:

    He may be referring to the fact that one of the benefits of 0g is that you can use every surface for something, including the ceiling.

    There's that, but there's also the sudden need for stairs and things like that. I don't know how much space that would take, but I imagine it's a lot.

  11. 9 hours ago, StrandedonEarth said:

    Into nearly identical orbits, with the mother of all cubesat dispensers...

    If the cost-to-orbit is so cheap, maybe it's no big deal to simply add a super-cheap propulsion, like a compressed air tank with a de Laval nozzle, for example.  I wonder how much delta v you could get out of something like that.

  12. Yeah, it looks like they got confirmation of booster destruction, but immediately after a "but don't say anything!!"...and then you can kind of see them backpedal and try to hide their emotions.

    As for the free ride on the Falcon, would have been a perfect opportunity to test that Cannae drive and put the whole thing to bed. Most of the arguments against doing just that seemed to be of the "putting it in space is too expensive" variety.

  13. Apparently there's also unknown and large risks when lighting up and firing 27 engines simultaneously as opposed to one, or only 9. Resonances, vibrations, whotf knows what else.

    If you ask me, if one works then you just add 26 more exactly the same. Should be mundane. 

    Good thing they're not asking me :D

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