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Low orbit is cheaper to get a satellite to just considering launch costs (less fuel, easier to recover the first stage), but as siblings have mentioned, it's mo

Low orbit is cheaper to get a satellite to just considering launch costs (less fuel, easier to recover the first stage), but as siblings have mentioned, it's more expensive overall, particularly considering that you need lots more satellites to provide coverage. Their plan to launch O(1000) satellites is to get lower latency and higher bandwidth, which would render the current generation of satellite internet obsolete. It's a great example of the sort of business plan that's only possible with cheap launches that SpaceX's reusable rockets have provided. Here's a more detailed primer: https://arstechnica.com/information-technology/2016/11/spacex-plans-worldwide-satellite-internet-with-low-latency-gigabit-speed/ https://arstechnica.com/information-technology/2016/11/space...

RivieraKid 8y ago
What is O(1000) satellites?
- oh_sigh 8y ago
  It's borrowed from comp sci, but you can read O(x) as "on the order of x", so maybe 900, maybe 1200, but somewhere around there.
  - loeg 8y ago
    In Comp Sci O() notation has a very specific meaning and "on the order of" does not approximate it. I think it was probably just a misuse of the notation.
    - gameswithgo 8y ago
      "The letter O is used because the growth rate of a function is also referred to as the order of the function" order of...order of yeah I know there is no "growth"
      - loeg 8y ago
        You've taken an informal and sloppy summary of big-O notation, isolated a single English expression, and construed that a similar English expression used in a different context with entirely different meaning is an accurate approximation of the formal meaning. You would be incorrect.
    - rak00n 8y ago
      I have seen it getting used in many places and it's understood as order of. O(n) means at worst case number of steps needed to complete an algorithm would be c.n + a. So it is completely valid use since O(1000) would mean it can be c.1000 + a, which actually means order of 1000s.
      - loeg 8y ago
        This is also an inaccurate description of the property O().
        rak00n 8y ago
        How so? https://www.khanacademy.org/computing/computer-science/algorithms/asymptotic-notation/a/big-o-notation https://www.khanacademy.org/computing/computer-science/algor...
        loeg 8y ago
        https://en.wikipedia.org/wiki/Big_O_notation https://en.wikipedia.org/wiki/Big_O_notation > Big O notation is a mathematical notation that describes the limiting behavior of a function when the argument tends towards a particular value or infinity. I.e., it's an asymptotic upper bound. It's also interesting to compare with Ω() (Big Omega — asymptotic lower bound) and Θ() (Big Theta) (big-O AND big-Omega): https://en.wikipedia.org/wiki/Big_O_notation#Family_of_Bachmann%E2%80%93Landau_notations https://en.wikipedia.org/wiki/Big_O_notation#Family_of_Bachm... A good textbook on this subject is Introduction to Algorithms: https://www.amazon.com/dp/0262033844/ https://www.amazon.com/dp/0262033844/ .
        rak00n 8y ago
        What I described is the same thing in layman's term. Worst case is the colloquial word for upper bound. And in that example n was approaching 1000. If you want to be puritan the only fault I see in my definition is instead of using a generic function I assumed it's linear function - but that's for explaining the colloquial use.
    - repsilat 8y ago
      In informal contexts it's also used as a fudge/handwave, purely as a questionable analogy that nobody is expected to take too seriously. `theptip` almost certainly knows that O(1000)=O(1), they were just being playful.
      - loeg 8y ago
        Exactly.
    - oh_sigh 8y ago
      I guarantee you can find dozens of examples of CS-type people using O() in non-algorithmic-complexity topics as "on the order of" or "approximately" right here on HN within the past 6 months. They aren't all misusing that notation - it is being co-opted into a more general lexicon, whether you like it or not. And I wasn't saying that "on the order of" is an approximation of what O() actually is in CS, merely that that is how OP used it.
- spiderPig 8y ago
  It's an unnecessary misuse of the Big O notation used to establish bounds of functions. I think they just meant up to 1000 satellites
- loeg 8y ago
  The author means literally 1000 satellites.
shaklee3 8y ago
No, it would not render the current generation obsolete. Not only that, but they are years away from having a fleet up there, and a decade from having the full fleet. Satellite technology progresses a lot in a decade, so you're doing the equivalent of comparing the iPhone 12 to the Galaxy s2.
- theptip 8y ago
  > No, it would not render the current generation obsolete. Why not? Just saying "you are wrong" doesn't really add much to the conversation. I'm interested to know more.
  - shaklee3 8y ago
    You're right, I should have explained better. If you take a look at many of the other satellites announced that don't get the same hype as SpaceX, you'll notice that they're comparable capacity, or have lower advertised capacity with other tradeoffs. SES mPOWER, viasat-3, and Jupiter 3 to name a few. The companies that stick to GEO satellites maintain that LEO satellites waste a lot of capacity over water, and there's nothing you can do about that. Not only water, but underserved areas that can't afford satellite technology are also included in this. Depending on the numbers you look at, this could mean the effective capacity of the satellite is ~10% of what is advertised. The other issue with LEO is that if you want to double your satellite capacity, you need to launch twice as many than you currently have in the sky, instead of just one or two more large ones. This presents logistical problems, and technical as well to some extent. When people typically refer to GEO satellites, they're unfairly making the assumption that the old crop of GEO satellites are where technology is today; namely fixed, low-capacity satellites. This is not the case. With the HTS (High-throughput satellites) and XTS (Extreme throughput satellites) that have movable capacity, not only do you have a comparable amount of usable capacity to LEO, but you can also move it as business needs change. The latency issue will never change, but if you see my other comments, I'm skeptical they'll be able to achieve the latency everyone is quoting.
    - theptip 8y ago

RivieraKid 8y ago

What is O(1000) satellites?

oh_sigh 8y ago
It's borrowed from comp sci, but you can read O(x) as "on the order of x", so maybe 900, maybe 1200, but somewhere around there.
- loeg 8y ago
  In Comp Sci O() notation has a very specific meaning and "on the order of" does not approximate it. I think it was probably just a misuse of the notation.
  - gameswithgo 8y ago
    "The letter O is used because the growth rate of a function is also referred to as the order of the function" order of...order of yeah I know there is no "growth"
    - loeg 8y ago
      You've taken an informal and sloppy summary of big-O notation, isolated a single English expression, and construed that a similar English expression used in a different context with entirely different meaning is an accurate approximation of the formal meaning. You would be incorrect.
  - rak00n 8y ago
    I have seen it getting used in many places and it's understood as order of. O(n) means at worst case number of steps needed to complete an algorithm would be c.n + a. So it is completely valid use since O(1000) would mean it can be c.1000 + a, which actually means order of 1000s.
    - loeg 8y ago
      This is also an inaccurate description of the property O().
      - rak00n 8y ago
        How so? https://www.khanacademy.org/computing/computer-science/algorithms/asymptotic-notation/a/big-o-notation https://www.khanacademy.org/computing/computer-science/algor...
        loeg 8y ago
        https://en.wikipedia.org/wiki/Big_O_notation https://en.wikipedia.org/wiki/Big_O_notation > Big O notation is a mathematical notation that describes the limiting behavior of a function when the argument tends towards a particular value or infinity. I.e., it's an asymptotic upper bound. It's also interesting to compare with Ω() (Big Omega — asymptotic lower bound) and Θ() (Big Theta) (big-O AND big-Omega): https://en.wikipedia.org/wiki/Big_O_notation#Family_of_Bachmann%E2%80%93Landau_notations https://en.wikipedia.org/wiki/Big_O_notation#Family_of_Bachm... A good textbook on this subject is Introduction to Algorithms: https://www.amazon.com/dp/0262033844/ https://www.amazon.com/dp/0262033844/ .
        rak00n 8y ago
        What I described is the same thing in layman's term. Worst case is the colloquial word for upper bound. And in that example n was approaching 1000. If you want to be puritan the only fault I see in my definition is instead of using a generic function I assumed it's linear function - but that's for explaining the colloquial use.
  - repsilat 8y ago
    In informal contexts it's also used as a fudge/handwave, purely as a questionable analogy that nobody is expected to take too seriously. `theptip` almost certainly knows that O(1000)=O(1), they were just being playful.
    - loeg 8y ago
      Exactly.
  - oh_sigh 8y ago
    I guarantee you can find dozens of examples of CS-type people using O() in non-algorithmic-complexity topics as "on the order of" or "approximately" right here on HN within the past 6 months. They aren't all misusing that notation - it is being co-opted into a more general lexicon, whether you like it or not. And I wasn't saying that "on the order of" is an approximation of what O() actually is in CS, merely that that is how OP used it.
spiderPig 8y ago
It's an unnecessary misuse of the Big O notation used to establish bounds of functions. I think they just meant up to 1000 satellites
loeg 8y ago
The author means literally 1000 satellites.

shaklee3 8y ago

No, it would not render the current generation obsolete. Not only that, but they are years away from having a fleet up there, and a decade from having the full fleet. Satellite technology progresses a lot in a decade, so you're doing the equivalent of comparing the iPhone 12 to the Galaxy s2.

theptip 8y ago
> No, it would not render the current generation obsolete. Why not? Just saying "you are wrong" doesn't really add much to the conversation. I'm interested to know more.
- shaklee3 8y ago
  You're right, I should have explained better. If you take a look at many of the other satellites announced that don't get the same hype as SpaceX, you'll notice that they're comparable capacity, or have lower advertised capacity with other tradeoffs. SES mPOWER, viasat-3, and Jupiter 3 to name a few. The companies that stick to GEO satellites maintain that LEO satellites waste a lot of capacity over water, and there's nothing you can do about that. Not only water, but underserved areas that can't afford satellite technology are also included in this. Depending on the numbers you look at, this could mean the effective capacity of the satellite is ~10% of what is advertised. The other issue with LEO is that if you want to double your satellite capacity, you need to launch twice as many than you currently have in the sky, instead of just one or two more large ones. This presents logistical problems, and technical as well to some extent. When people typically refer to GEO satellites, they're unfairly making the assumption that the old crop of GEO satellites are where technology is today; namely fixed, low-capacity satellites. This is not the case. With the HTS (High-throughput satellites) and XTS (Extreme throughput satellites) that have movable capacity, not only do you have a comparable amount of usable capacity to LEO, but you can also move it as business needs change. The latency issue will never change, but if you see my other comments, I'm skeptical they'll be able to achieve the latency everyone is quoting.
  - theptip 8y ago