Mind boggling. If author is around here I'd love to know how much time did this project require. Everything seems so polished. Aesthetics alone are something that many big projects could learn from.
> I explicitly do not authorize any organization or entity to cite this article, or the results obtained by the simulation, for inclusion in filings with any regulatory body under any jurisdiction.
Interesting. I wonder if you’d actually need the author’s authorization to cite his work in such a way.
I get where he's coming from. There's a maritime protocol for ship location, AIS, mainly meant so ships can all have nice radar-like displays of the ships around them. I wrote a decoder for it for an art project, the Twitter bot @sfships. I was very concerned that somebody would take it too seriously, so I wrote:
"I needed a simple AIS decoder for a small art project. I couldn’t find one, so I’m making something minimally adequate for my needs. Decoders are generated automatically from public protocol documentation, but since I use few of the fields myself, I haven’t verified much of the decoding. This code is rough and doesn’t worry much about correctness, and so shouldn’t be used for anything that matters. It especially shouldn’t be used for ship navigation." -- https://pypi.org/project/simpleais/
Sure, but an opposing party could then easily call it out as bad evidence. "Commissioner/your honor, the author themselves didn't this was any good for use in court".
You don't need the author's authorization. However, any regulatory body reviewing your filing and following up on your sources might find your choice questionable.
If feels a lot like those YouTube uploader disclaimers to me: makes the author feel good, but probably won't mean much in a court of law - if it comes to that. IANAL
Outstanding work, I wrote an incredibly naive simulator of Starlink coverage using H3 over a year ago before we even knew that Starlink was using H3 internally. The community over in r/Starlink wrote some other simulations too and we all stopped short of actually calculating based on gateway reachability and ISLs weren't in use yet either.
This is some really fantastic, detailed analysis. I'm almost always impressed by the synthesis of knowledge required to be authoritative on expansive topics like this one.
Something not covered in the article, but I have wondered about. How does Starlink do the handover? The satellites are in Leo and thus have orbit times of around 90min or so (not sure about the exact number), so every cell must be served by several satellites at the same time no? Otherwise we would see significant interruptions at the handover.
The beam hopping (TDM) part of the article is similar to satellite handover. There's a lag before a beam returns to a location or a new beam is over a location, and the beams can't overlap (nco=1).
well, some (or all?) have laser links now, so as another sat gets covisibility with a ground station and user terminal, it can just instantly pass the traffic off
without laser link, it's looks to me that most of the time in populated latitudes, there will be more than one sat's beams covering a cell, and if not then there would be interruption in coverage
the terminal should handle transmitting to multiple sats that are close by, but i dunno how omnidirectional the dishy is
I'm not understanding why Starlink is limited in terms of how many cells it can serve by beam hopping. What's driving the analyst's choices for the different "TDM split" and "beam spread" values? I naively expected the system to have much more granularity than 10% TDM splits.
Beam hopping adds latency and jitter because packets have to wait for the beam to become available. For example if they use a ~1 ms superframe and they want to limit jitter to 20 ms they couldn't split more than 20:1.
Beam hopping also cuts available throughput. If they're promising 100 Mbps they can't slice things too finely.
Thanks for the explanation. It raises the next question about how small a superframe can be, which I imagine as they get smaller makes efficient scheduling a more difficult problem.
Funny people think Starlink is mainly a commercial enterprise. Since Teledesic in the 90s, these low earth orbit constellation projects have always been about stepping towards the real goal, which started with Strategic Defense Initiative and now embodied in the Space Development Agency
Don’t worry you tried to look too closely at a conspiracy theory and it fell apart.
A clasic conspiracy theory is basically conformation bias run wild. So someone thinks “thousands of satellites must be useful for X” but never really look into just how tiny each individual satellite is and how much of that must be used to fulfill it’s cover story.
I can see why you would get confused, this is using elements from Starlink satellites the so called “Starlink bus” not the constellation.
-The Space Development Agency awarded $193.5 million to L3Harris and $149 million to SpaceX to build four satellites each to detect and track ballistic and hypersonic missiles.“
-“We want to show that we can take commoditized commercial components and perform a DoD mission,” said Tournear.
Sure when the military wants more they have no issues building and launching satellites.
The point still stands, it’s clear the Starlink constellation is independent. They are simply reusing a useful platform the same way the DoD buys PC’s etc.
If new sats can use t-mobile LTE network what stops them from being used as global Stingray/IMSI-catcher? At the very least they will be wardriving, but thats likely been done ages ago by several operators.
Former general, and the military is a huge potential market for Starlink’s network or as he proposed in 2019 possibly a new DoD specific constellation.
The issue with Starlink’s network is they don’t have polar coverage which is needed due to nuclear subs in the Arctic Ocean.
Coverage of the Arctic Ocean is insufficient for ground observation. It could change but would be really obvious as you would have polar orbits through the Pacific Ocean which would be really wasteful for their business model.
The biggest driver of weaponization of space is Putin's nuclear saber rattling, space companies have always been in service of defense contracts. You want to see a real budgetary boondoggle? I give you the United Launch Alliance.
Just like the biggest driver of EV car adoption at the policy level is Puting, current gas prices, inflaction, and OPEC trying for more profit mongering.
Frankly I'm mystified as to why Musk posted that weak tweet to ending the war. He's in the perfect situation to be a war profiteer, and he doesn't even provide weapons.
But to the conspiracy nuts out there, the constellation is perfect cover for a smart rock interception network.
I think the idea would be you need to empower the network of satellites in the sky to react quickly to a nuclear attack from another country, so you need to allow this “sky-net” to launch nukes at a moments notice without human intervention.. it likely would need a human level intelligence to quickly asses the level of risk. And to avoid being hacked, you would want this AI to be able to protect itself under various circumstances. Sounds reasonable right?
That whole spacex origin myth is ridiculous. Musk goes to Russia to buy an ICBM? Right. Then, having never touched a rocket, Musk is given $400M to start spacex? Ok.
"In 2002, Griffin was President and COO of In-Q-Tel, a private enterprise funded by the CIA to identify and invest in companies developing cutting-edge technologies that serve national security interests. During this time, he met entrepreneur Elon Musk and accompanied him on a trip to Russia where they attempted to purchase ICBMs. The unsuccessful trip is credited as directly leading to the formation of SpaceX.[11] Griffin was an early advocate for Musk calling him a potential “Henry Ford for the rocket industry".[12]
After In-Q-Tel, Griffin served as Chief Engineer and Associate Administrator for Space Exploration at NASA Headquarters.
In 2005, he was appointed NASA Administrator where he conceived and introduced Commercial Resupply Services and crew transportation services for the International Space Station.[13] Twenty aerospace companies applied to the Commercial Orbital Transportation Services (COTS) program, but only SpaceX was selected and given $396 million--a surprising bet given the new company had never flown a rocket.[14] In December 2008, with SpaceX again on the verge of bankruptcy, Griffin awarded SpaceX along with his own Orbital Sciences company each contracts with a combined value of $3.5 billion.[15] Elon Musk credited the NASA contract as saving his company.[16]"
If Musk can be said to have founded Tesla because he was an early investor, then the same logic must apply here. Musk was given $400m by the government before ever flying a rocket.
That’s mangling the timeline a little. SpaceX was founded in 2002 and started launching rockets in 2006, it also received the NASA contract in 2006.
SpaceX didn’t have a successful launch at the time let alone a proven system, but they had plenty to show. Further they where one of 2 winners splitting the initial 800M budget for COTS with Rocketplane Kistler. They are remembered because Rocketplane Kistler failed. https://en.wikipedia.org/wiki/Rocketplane_Kistler
Also the COTS award was delivery-based. They didn't get paid unless/until they delivered a working rocket. Had SpaceX failed on their first 4 attempts, which was paid for almost entirely with Musk's initial investment, then they wouldn't have seen enough of that COTS contract award.
According to Mike Griffin who gave them the money,
Substantial amounts of money, hundreds of millions of dollars, are being provided to the private companies. If SpaceX continues on along its current path, it will have received approximately $1.2 billion in government money from the collective programs. I’m rounding, but with this recent $400-plus million award under CCiCap [Commercial Crew integrated Capability], that brings the total SpaceX funding to something around $1.2 billion, maybe a little more.
That’s—I will only say in my view—excessive, especially since in testimony last year the SpaceX founder, Elon Musk, indicated that the private funding involved was not more than $200 million. $100 million of his own money that he had brought in from a prior enterprise, and then he alluded to the fact—I’m trying to recall the testimony on an ad hoc basis, but the point is that there’s less than $200 million of private capital in SpaceX and $1.2 billion of government capital.
(Michael Griffin worked closely with Elon before SpaceX was founded at the Mars Society and worked on Brilliant Pebbles and DC-X which the Falcon 9 was based upon)
Given all that government money, it was a low risk private investment for Elon.
The government contracts wasn’t free front loaded money, it was a maximum possible fee for services rendered. And frankly the R&D NASA paid for was largely stuff like the capacity to dock with the ISS and deliver cargo which was only relevant to them
Fix cost government contracts can look really awesome when they work out, but they are not a 1:1 equivalent to private funding. Essentially what you need to look into is what percentage of that money was profit and assuming say a ~20% profit margin it works out to something like 200 million from the government and 200 million from private investments.
Out of curiosity, I read the COTS Space Act Agreement. It's a crazy good deal for SpaceX. They got their first $200 million just for doing presentations to the government and writing down requirements. This effectively front-loads funding because doing the qualifying milestones 1-12 are cheap (PowerPoint), yet $200M is certainly enough to actually build and launch an entire rocket.
As the sibling comment mentions, these were not front-loaded contracts. There were some initial payments made for Falcon-9 feasibility studies and stuff related to ISS rendezvous and docking. It basically paid for spinning up a small team of engineers to work on those issues specifically. But the actual rocket development was 90% paid for by Musk, and no more than 10% paid for by early customers like Malaysia and the Air Force Academy. By the time of the 4th Falcon 1 launch they were out of money, and the COTS award was entirely inaccessible to them unless they managed to make it to orbit, which they did.
I remember this quite well--I was at NASA at the time of this contract award. It is also written up in the book Liftoff if you want to see for yourself.
That's simply incorrect, see the COTS Space Act Agreement above. Those "initial payments" to SpaceX totalled $200M just to do presentations (more than double what Elon's total investment ever was).
The book Liftoff is mostly Eric Berger regurgitating an origin story Elon told him, not reality.
Those presentations required actual trade studies which take significant work to prepare. It’s not a matter of just showing up and winging a PowerPoint presentation, lol. By that metric a PhD is just a PowerPoint presentation.
They were weeks away from not making payroll before they received customer down payments and bridge financing following the successful launch of Falcon 1.
This is all covered in Liftoff. It’s a good book; I recommend reading it.
There might be something to it. I work for a fortune 500 company and we've been trying to get in contact with them about a project we're working on for the last 12 months.
Firstly getting any contact details like a phone number or email is close to impossible. Then you just don't get any response from them anyway.
It just looks strange.
This is a hilarious characterization given his companies actually manufacture physical goods and capabilities, revolutionary ones at that, while most of the people here work at funny money companies moving bits around to achieve unicorn valuation via hype and "exit".
And even more hilarious that this comment is a garden variety take from armies of anti-Elon posters that are astroturfers. The word "Elon" is an internet lobbying battleground (and there are likely armies of pro-Elon roboposters). Armies driven by, at least initially, by funny money hedge fund bets. Bets that would have come true about 5 years ago if Tesla/SpaceX were pure hype/bullshit.
SpaceX/Tesla are tremendously high valued because they still have an order of magnitude or two of readily apparent growth. And a CEO's job of growth companies is to hype that growth, to drive investment/stock price, which drives the scaling and R&D.
Uber: well. they do provide a physical service. It's just a taxi company at an app with google maps, but, I guess it is a physical service.
Meta: once a monopoly, only exists due to ad fraud, and turnkey Big Brother infrastructure
Google: still a monopoly, but also only exists due to ad fraud, and also provides turkey Big Brother infrastructre
What about my comment struck you so deep to the bone that you wondered what my "emotional attachment" to the media construct of Elon Musk is? Did I make it seem like I love Elon Musk and wish he'd return my phone calls? LIke I have some fucking shrine with his awkward mug on it? I do, but it's from when he was balding.
How about you, 'idiotsecant', you seem emotionally invested to some pointless deep thread on something with the keyword "Elon Musk", what motivates your subconscious after spending 10,000 hours deep in social media and speculating on crypto?
God forbid someone tries to apply some rational thought to "Elon Musk is the WORST" twitterlogic grouphate. The ISSUE IS that the entire world's panties are in a bunch over Elon being the "worst person ohmygod" when if you rank him in "worst CEOs in the world" he's probably about #20,000 after mining execs, petroleum companies, bankers, pharmaceutical companies, automotive execs, amazon execs, facebook/google, sweatshop manufacturers, meatpackers, pesticide makers, plastics companies, Xe, security companies, shipping, defense contractors, firearms manufacturers ... It shows a complete lack of understanding of the world and the serious shit we are in.
Of course this manipulative bullshit you just posted means you're equally ignorant, even if you think you're not. Christ, and your day job is in alternative energy, you should know better. That's depressing.
I think the fact that you spent your free time digging way into the post history of some stranger and writing this wall of text in response to a one sentence long throwaway comment that wasn't even from the person you were originally arguing with proves my point.
Because ballistic missile defense is an aggressive nuclear action, potentially allowing the country that has deployed such a system to launch a nuclear first strike without fear of retaliation. It would entirely destroy the "mutually-assured destruction" balance of power system, and would almost certainly be seen as an act of aggression by all other (non-allied) nuclear powers.
Also, why not also commercialize it, if it's simple? Just because you're being subsidized by tax payers doesn't mean you can't turn some extra profit.
>I explicitly do not authorize any organization or entity to cite this article, or the results obtained by the simulation, for inclusion in filings with any regulatory body under any jurisdiction.
Would this be in anyway binding? Can you say someone is not allowed to link to my blog?
> The calculations required to run a single snapshot can become massive, taking up considerable CPU resources from your computer, and locking the browser for a long time. A large country with 30k cells, served by 150 satellites, each with 48 spot beams, could require up to 216 million calculations.
216 million functions involving a few FP operands is going to take multiple seconds of CPU compute if the entirety of the CPU cycles were efficiently dedicated to said compute, due to the single thread nature; so I would guess yes, it's a fair amount of compute for a phone or something that will use loads of cycles on other scheduled topics
I'm truly impressed / shocked that people have the capacity and will to be build such amazing things as side projects!