Falcon 9 / Dragon

Discussion in 'Science' started by MoorKhan, Dec 8, 2010.

  1. aokman

    aokman Member

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    I don’t care Ill take the first ticket off this rock :lol:
     
  2. whatdoesthisdo

    whatdoesthisdo Member

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    So incredible that at one stage astronauts and NASA were laughing at Elon even suggesting of reusing rockets and now they just land so casually in the back ground.

    what a world all right.
     
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  3. aokman

    aokman Member

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    Another interesting tid bit from the press conference, it was thought the Super Draco’s were single use now with the burst discs but Elon confirmed the engines were actually throttled down to minimise G’s during the escape which implies they still have potential hover and reigniting capabilities... rather than single use balls to the wall acceleration.
     
  4. SLATYE

    SLATYE SLATYE, not SLAYTE

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    The burst discs (and the check valves they replaced) are just for startup, to prevent getting fuel/oxidiser mixing in the pipes before they're both at operating pressure. I expect they still have regular flow control valves to adjust the thrust level once the engines have started; how else would they control the capsule?

    I'm pretty sure the burst discs have to be replaced before they can safely re-light the SuperDracos.
     
  5. Sphinx2000

    Sphinx2000 Member

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    How SpaceX's starlink satellite Internet network works, and how it will operate with lasers that are actually faster than existing under-sea fibre cables!

     
  6. aokman

    aokman Member

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    Can’t wait for Starlink to bury NBN in a deep, dark, hole.
     
  7. Quadbox

    Quadbox Member

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    It wont, though? It doesnt have even close to enough total bandwidth in highly populated areas, even elon's stated that it wont out compete fixed-line services in large cities. The only part of the NBN it's going to be competitive with is skymuster and the fixed wireless footprint. Now I'm excited for *THAT*, given I'm moving rural, but it's simply not going to replace high speed fixed-line broadband in major cities
     
  8. aokman

    aokman Member

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    I think you are confusing 6 month old Starlink speculation. Latest iteration will have lower latency and high bandwidth. Light travels 52% faster in a vacuum than in fibre and total bandwidth of Starlink is irrelevant as the majority of data will take place through local dynamic mesh connections that are built and broken down as needed.

    Personally I think Starlink will be the end of terrestrial communication systems. Not to mention it is powered by renewables and creates big savings for the environment.
     
  9. Quadbox

    Quadbox Member

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    You're conflating the inter-satellite network with the terrestrial to satellite RF side of things, which is still fundamentally limited by RF bandwidth, a shared resource. This is true even when you're using phased array beam steering, as the sidelobes are *always* non-trivial. No matter what you do, physics highly limits the total amount of shared RF bandwidth available within line of sight, and that is a function only of the frequency band(s) available, with some single order of magnitude mitigation from spacial multiplexing. It is certainly true that starlink has some advantages in spacial multiplexing over, say, cellular networks. But it is not two orders of magnitude here. Fundamentally this technology is about cheaply providing high speed network access to areas where it ISNT currently available. It is a nonsense to say that it will be capable of providing high speed internet to every potential user in a densely populated city simultaneously, physics simply does not allow that.
     
  10. tobes

    tobes Member

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    Yikes, that is an insanely big call. There is 0% chance that Starlink and any of the current Near Earth Orbit technologies can replace terrestrial comms. With antennas every 50m in the CBDs we struggle to deliver reliable high density mobile solutions.
     
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  11. aokman

    aokman Member

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    That is nothing more than speculation at this point, we have 0 real world experience with satellites operating at such a low orbit, in large numbers or how SpaceX will implement the terrestrial links.

    They would not be building a network of up to 40,000 satellites to go after 3rd world countries for revenue. They are going after the big piece of the pie and they wouldn’t be going in balls deep without a rollout plan. Then again people love to think SpaceX are in over their heads up until the point that they are made redundant.
     
  12. aokman

    aokman Member

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  13. MUTMAN

    MUTMAN Member

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    I dont get the hate ?
    no need for fanboism in the race to make the world a better place
     
  14. aokman

    aokman Member

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    It has nothing to do with fanboyism... they are a shit company propped up by politicians, the 737 MAX fiasco is the best example of that. They failed to reach the ISS, had a parachute fail on landing leaving no redundancy and now thruster failures and they are still pushing to launch crew before SpaceX who have done everything by the book and in some cases done more than they had to just to prove a point. They have not even proven they can reach the ISS successfully and dock but they want to be certified as human rated? That is friggin insane.

    A crew launch with Boeing costs roughly 150mil more per flight compared to SpaceX or almost double per seat and the booster is fully expended creating even more waste not to mention less abort options due to the SRB's, they are living in another century of technology, relying on big corrupt budgets to keep funding their ridiculous wastage. Think of any other market where a customer is going to pay an extra 150mil premium over a competitor while using them both concurrently. Not to mention the large bags of cash that were handed over as cost + contracting.
     
    Last edited: Jan 30, 2020
  15. MUTMAN

    MUTMAN Member

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    i cant help but think the airplane team has not much at all to do with the space team
    doesnt sound right to me either, but i aint an aerospace engineer, so i'll leave that to the experts at NASA. cause it's their money they're blowing. not mine
    much like my comment above. why do you care if they charge more ? it doesnt cost you or me or AU a cent.
    again i'm guessing at things here, but i imagine NASA have some criteria that I dont understand (maybe you do ?) that they are evaluating by having three teams go head to head.
    just because one team finishs first doesnt mean the others should just pack up and go home. besides, i thought that would be good for spacex, and you'd be heavily in favor of that
     
  16. Quadbox

    Quadbox Member

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    Treating this thread more as a general space commentary, can I be the first person here to say that trump's nasa budget proposal today is stupid on oh so many levels. I know I'm a physics guy, so I'm a little biased towards the idea that a science organisation explicitly set up to perform science should focus first and foremost on, you know, science, not on a pissing context. Cancelling WFIRST *and* SOFIA would be *unfuckingbelievably* short sighted and stupid. I'm hugely enthusiastic about human spaceflight, but those two observatories are *important*.
     
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  17. Ratzz

    Ratzz Member

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    Its politics, not science. They have to be seen to be impartial, giving bucks to a few companies and seeing which one achieves the most with it. Simply picking one/the best company or approach would *appear* to be favouring one company over another. God forbid that they just choose a winner and throw all their cash into backing the best and ditching the rest.
     
  18. Quadbox

    Quadbox Member

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    Yeah and as at least two commentators I've seen have mentioned, JWST is built by northrop grumman, who have politicians in their pockets and a vested interest. SOFIA and WFIRST are both orphaned from any major corporate involvement (despite being built out of parts built by boeing and lockheed martin). Draw your own conclusions. There are astronomers in MY physics department who are actively running research on SOFIA as we speak, it's of global importance. Ditto the cosmologists interest in the capabilities of WFIRST. JWST is fucking important, noone is denying that, least of all me. But I think artemis is largely a penis extension attempt by a president with a famously short member and zero interest in nuance.
     
  19. mr camouflage

    mr camouflage Member

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    Starlink freaked out some kiwis a couple of weeks when they were spotted in the night sky.

    https://www.sunlive.co.nz/news/233416-starlink-not-aliens-to-appear-again-tonight.html

     
  20. Sphinx2000

    Sphinx2000 Member

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