[AR] Re: Aw: Re: Future Exploration Policy (was Re: Re: Congrats SpaceX

  • From: "Jake Anderson" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender "jake" for DMARC)
  • To: arocket@xxxxxxxxxxxxx, David Summers <dvidsum@xxxxxxxxx>
  • Date: Fri, 23 Feb 2018 10:18:30 +1100

I really don't see this happening.
My prediction is GEO is dead for comms and dying for most other uses.
The 600mS round trip latency is just too high for humans to deal with and is terrible for computers as well.
SpaceX (and others) are launching LEO clusters that'll give global network coverage with something like 5 sat's in view at a time (if my maths is right)

Outside the big cities this will be a game changer. Inside cities perhaps less so but if I were a fixed line provider I'd be running fibre to the premises now while the money tap is still open so that you can offer a better service than the various LEO internet networks will be offering in 20 years time. With falcon heavy or BFR around a few launches would net you 50 satellites in view, with phased array antennas on both sides bandwidth should be impressive and handling moving (cars and boats etc) should be "easily" solved. I don't think initially phones would be covered outside of some low bandwidth mode (like 1mbps) just due to power requirements on the ground station side as well as difficulty with operation inside buildings etc.

GEO is only really going to be used for broadcast which is becoming less and less popular (Netflix anybody?)

Cluster sat's are probably going to replace GEO weather sats eventually. Why build one big giant sat, then sit it 30,000km away and looking at a big angle at what your interested in when you can build 10 smaller sats, sit them 800km away and get true global coverage whilst looking straight down.

I hope the UN or somebody gets their ass in gear before too long and regulates clean-up in space before all these clusters cause Kessler Syndrome.
IE part of your launch licence is active deorbit and insurance for a third party to provide deorbit service in the event of a failure.


On 10/02/18 08:23, David Summers wrote:

Heh, I am technically an EE, but I don't currently work on radios.  Spread spectrum techniques don't create more bandwidth, unfortunately.  They just make it easier to avoid interference and hide communications.  The only way to "create" bandwidth is to use different paths.  For example, with infinite funds one could build a phased array satellite several kilometers wide in GEO.  You could then have multiple overlapping conversions with several different Earth-side locations, each using the full bandwidth available - and the Earth-side of that wouldn't have to be anything special to receive it.

Of course, I'd personally use infinite funds for other purposes.  But you can do a lot if you really want to.

Thanks!

-David Summers

On Fri, Feb 9, 2018 at 3:15 PM, Paul Mueller <paul.mueller.iii@xxxxxxxxx <mailto:paul.mueller.iii@xxxxxxxxx>> wrote:

    I'm no EE (it's all magic to me), but I was thinking about things
    like frequency hopping, used for lots of transmitters and
    receivers in close proximity (e.g. RC aircraft). Maybe that's not
    an option for going 22,000 miles with one end that's very
    difficult to service--I could be totally up in the night. But I
    also figure those EEs are pretty clever and have all kinds of
    tricks up their sleeves. Especially when big bucks are involved!
    Certainly seems the trend is for the world to get much more
    interconnected and GSO seems much more attractive as launch costs
    go way down. I'm wondering if Project Loon (balloon-based
    internet) will also be a casualty. But that gets into
    distance/bandwidth tradeoff, too. Just non-EE speculation.

    Taking a step back and looking at the big picture, I think the
    "sci-fi" future will involve a robust ring of GSO satellites
    interconnecting the world (MUCH more than they do now). We may
    look back on the FH launch as a major turning point in enabling
    this. Maybe not as dramatic as the steam engine enabling the
    locomotive and the rail networks across continents, but similar.

    On Fri, Feb 9, 2018 at 9:56 AM, <Nels.Anderson@xxxxxxx
    <mailto:Nels.Anderson@xxxxxxx>> wrote:

        > Gesendet: Freitag, 09. Februar 2018 um 17:34 Uhr
        > Von: "Henry Vanderbilt" <hvanderbilt@xxxxxxxxxxxxxx
        <mailto:hvanderbilt@xxxxxxxxxxxxxx>>
        >
        > Redstone Arsenal in Huntsville and its resident
        > Army Ballistic Missile Agency, AKA Von Braun's rocket team,
        were folded
        > into NASA back at NASA's start in 1958.

        To make a very minor point: it wasn't until September 1960
        that the von Braun crew came to NASA. Otherwise, I agree....




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