SpaceX sends laser-linked Starlinks to the polar orbit
teslaoracle.com
teslaoracle.com
The value that sat-to-sat laser links provide is that they create a low latency, high bandwidth path that stays within the Starlink satellite network. Before these 10 satellites, each Starlink satellite has only been capable of communicating directly to ground terminals (either consumer, transit, or SpaceX control). For traffic that is intended to move large geographic distances (think transcontinental), this can require several hops back and forth between ground and space, or the traffic from the user terminal is exited at a node that is geared for transiting traffic and most of the data transits along existing ground Internet links.
By performing this type of transit directly in space, and exiting at a transit node nearest the destination for the data, you greatly reduce latency. Bandwidth still might not be great, but what this does is unlocks a very financially lucrative consumer use case: low latency finance traffic and critical communications. There are many use cases around the world where shaving even 10-20 milliseconds of latency on a data path can unlock finance and emergency capabilities, and this is a long fought battle throughout the history of these industries. As an example, if you got a piece of news about a company in Australia, and wanted to trade on it as quickly as possible in USA, if you can beat your competitors by 10-20 milliseconds, that can mean a lot of money.
Laser comms for Starlink sats have long been planned, but have historically proven to be quite hard to get working. They also depend on a sufficient critical mass of satellites so that a given sat actually does have another sat within lock to send the traffic towards.
The telemetry and tracking itself for the laser links. All the satellites need fairly accurate orbital information from all other satellites; there will be several thousand satellites capable of performing autonomous orbital adjustments to avoid debris and for their own station keeping. There has to be a convenient and reliable fallback for automatically syncing satellites with the rest of the network after a reboot or loss of communication.
The packet network needs to maintain an efficient routing table and provide low packet loss to end-users. My guess is that the only practical choice will be establishing a large number of point-to-point channels with their own retry/error-correction management. TCP/IP isn't capable of dealing with more than about 1% packet loss and I doubt raw optical/wireless links will be reliable enough especially with topology changes, requiring extensive store-and-forward hardware to buffer transmissions waiting for a reliable route or de-duplicating multicast packets at the receiving end. Reassembly and de-duplication on receipt is theoretically feasible; if a tight reception window can be maintained then specialized hardware could filter duplicates sent over 2 or 3 redundant routes to a local receiver without increasing observed latency or using unreasonable amounts of RAM. A combination approach could allow a tradeoff between using double or triple the raw bandwidth but providing low-latency reliability vs. higher latency with retries while maximizing throughput depending on the current network load. It could also be hardcoded for different traffic classes.
I'm not involved in this problem space in any technical capacity but it sounds like a very fun set of problems to solve.
Accurate orbital information might not be necessary or possible, if you can perform broad scanning that can quickly lock in your given target, but it certainly doesn't hurt. The issue is that even having an orbital track, because of the sats being so low in LEO, atmospheric drag will change your orbit rapidly enough that this information can get out of date quite fast.
Convenient and reliable fallbacks I feel are largely a solved problem for SpaceX. They've built their Starlink bus by reusing a lot of the software from the Falcon 9, Dragon, and Starship programs that already had to handle even greater levels of reliability.
Routing and retransmits are indeed quite a novel area for this kind of service. But the laser link will only be locked on one other peer satellite at any given time, and I don't think they plan on reorienting the sats in order to establish laser comms because of the effect it would have on drag as well as albedo. The former impacts service life per sat, and the latter has been a big rallying cry for Starlink opposition due to the impact it has on astronomy and the visible sky.
So if you likely can't reorient to retransmit, your only options are the peer laser link or the ground transit exit node, either or both of which might not exist, but I feel like you would just ack the packets on each hop to your peer and leave it at that.
http://www.circleid.com/posts/20190906_inter_satellite_laser...
While a major leap, Starlink could potentially service internet backbone traffic at substantially lower latencies in such a world.
You can control the overhead while increasing recovery rate over multiple paths fairly well, with non-integer overhead (>1x but <2x, etc) with erasure coding techniques. Some erasure codes can allow you to control that overhead (code rate) precisely, but have legal imbroglios: https://en.m.wikipedia.org/wiki/Fountain_code
Having said that, I don't think this situation will apply to spacex. They probably won't get random bursts of errors. Noise levels will be very deterministic and can be calculated ahead of time by looking at what stars are "behind" the satellite.
I'd love to be on the Starlink team, they are building some really cutting edge stuff. There are not many places or times where you can have such a big impact on the world and their team happens to be one of them. Good times.
[1] https://www.sciencedaily.com/releases/2020/05/200522095504.h...
They're incredible :)
Then there's the issue of signal attenuation at distances like these, along with the power budget from the solar panels to ensure that you aren't burning all your power just on laser comms.
I can't imagine these links would be anything more than 1:1 at any given time, at least not at first. Maybe later they might be able to handle simultaneous laser links from 1:3 or something like it, but I highly doubt that's their current capability.
Even some of the best latest ground-to-sat laser comms links are on the order of ~7 gigabits per second. [1] I imagine those are far larger sats than Starlink, and their entire power and thermal budget is likely spent on comms. And the ground stations can be orders of magnitude larger and power hungry in relation to a Starlink sat. Note also that this is from GEO, so you aren't likely having to handle substantial relative movement either.
[1] https://en.wikipedia.org/wiki/Laser_communication_in_space#2...
Satellite-to-ground optical laser links are another matter, but you can always route a few hops around weather systems.
https://www.spacex.com/careers, category "software development".
But I do see on the careers page there's now a (single) Palo Alto based Software Engineer position open.
Intriguing!
The second challenge is that I am in a position to be reasonably frank when the biggest threat one can hold over me is to be fired. I have found that some managers don't appreciate employees for whom their "hire/fire power" over them doesn't give them any leverage. This combined with a general perception that I am a good manager, means that I tend to develop a followship whether or not I'm in a leadership role. This can lead to "issues" no matter how hard I try to prevent them.
Or does the "eligible to obtain the required authorizations from the U.S. Department of State" apply?
If I were you, I'd read up on ITAR qualification and, if you think you would be eligible and are highly qualified, just apply.
and also relatively overhead of the CPE antenna, since the starlink customer terminal is a phased array that does dual beamforming in a 'cone' of view directly above it. just because a satellite is visible 5, 10 or 15 degrees above the horizon from the POV of the CPE doesn't mean it can talk to it. the system is definitely reliant upon a fairly high satellite density.
with the ability of the satellite that's generally overhead of a starlink earth station to talk to the satellites immediately behind, and preceding it in its orbital plane, and then those two additional satellites to talk to the CPEs underneath them, the possible coverage area can be greatly increased.
3D visualization of starlink orbits and coverage footprints:
Right, compared to reasonable in-ground ISPs.
I think Starlink sat to Starlink sat links will also help bandwidth, specifically in the case where a given downlink connection is heavily utilized, the system can shunt traffic to another slightly less ideal but less utilized ground station.
> unlocks a very financially lucrative consumer use case
That's a bingo! I think there's a pretty good chance that this could turn into a pretty epic cash cow for Starlink.
it's very low data rate but also guaranteed lower latency than the submarine cables.
Maybe with that out of the picture other uses like telepresence for remote surgery can edge in. I've been waiting for a while for that to really take off seems like an awesome way to provide services you couldn't afford to to remote places.
I have read that Starlink, given sat to sat relays, should be able to beat any possible ground based system as long as the distances are great enough. Does that match your understanding of this?
Starlink is at a disadvantage because fundamentally it's pathing across a sphere with a larger radius so even when the path is direct across the Starlink cluster it still has to traverse a longer distance than the equivalent path on the ground. Adding to that the path won't always be directly across the surface of the constellation, depending on where you are and where the destination is you'll find some pockets where the link has to zig zag across the constellation slightly adding to the additional link distance. This [0] isn't necessarily a perfect representation but it does show how starlink's linking may work and how it's not a perfect net. It also doesn't account for the acquisition times for new laser links which were on the order of 20 seconds in another laser sat link test.
[0] https://youtu.be/AdKNCBrkZQ4?t=103 (it's also comparing fiber to Starlink where the best in class now is radio links generally)
> where the best in class now is radio links generally
What would I put into a search engine to learn more about these more recent long distance radio links? Thanks!
There are atmospheric and practical effects that make going more than 50-60km with PTP microwave, and data rates above 700-800 Mbps, increasingly costly as the distances increase.
It is totally possible technologically to build very long chains of many microwave PTP radio hops, as some high frequency trading companies set up between new york and chicago, but the aggregate throughput and capacity is minuscule compared to fiber.
Would be happy to answer any more specific questions.
Here's an example of a current state of the art point to point microwave radio, for use in the common FCC licensed part 101 bands (6, 11, 18, 23 GHz, etc)
https://aviatnetworks.com/products/all-outdoor-radio/wtm-400...
if you google 'starlink train' and look at some videos, when a batch of 60 starlink satellites is launched ,they're all at the same orbital inclination. they remain at the same inclination but as the weeks go past after their launch, they are spread out to follow each other at several hundred km spacings. but they're still following each other in what is basically a strung out conga line of satellites. communications between forward/rear satellites in the same batch should not be nearly as difficult to aim.
what would be difficult to aim and maintain links on would be cross-plane links between two different sets of satellites, with very high differing relative velocities.
I dug up the paper with the technical details.
I did not find anything suggesting it'd be used productively for the satellite if it manages to deliver. Do you have anything about that you can tell/link?
I'd be curious what the initial design weight was, before the thermal expansion problem that caused the aluminium block.
As for the data rate, it seems a mechanically simplistic fold-out mirror (released during deploy, say with a current pulse into a shape-memory-alloy torsion spring to delay the unfolding until after the ejection, or just a simple friction break and a normal torsion spring) could significantly decrease the beam width when made from e.g. zerodur and fabricated as an offset parabolic dish. Slightly modifying the refractive collimating optics of the current design should make that approach possible.
I'd expect vibration in space to be a negligible issue, so an edge-mounted mirror should be stiff enough.
https://elib.dlr.de/135960/ https://elib.dlr.de/135960/1/1150604.pdf
In GEO that's not a problem - a lot of the planet is in sight. You have a ground station in New York and you can bounce off a satellite over the Atlantic and land the signal in Nigeria just fine.
With Starlink the orbits are really low, so the distance to the ground station is low. That's fine if you are in the backwoods in Washington and bounce to a receiving station 100 miles away in Seattle, it's no good if you're at sea, or (in this case) at an Antarctic station -- one which can't even see GEO satelites.
it's the pole that has problems seeing geostationary, and has up until very recently been totally dependent on 7-8 hours of coverage a day using big tracking antennas to talk to old geostationary satellites that have wandered somewhat out of their original orbits, so that from the POV of the earth station at pole, they can be communicated with part of the time.
Most data and internet from pole is via ~4 hours of DSCS a day, ~4 hours of skynet (slowww...) or when TDRSS decides to gives South Pole time (but in small chunks of time).
I usually try to ssh in my experiment at Pole the start of DSCS time, which unfortunately can be in the middle of the night for me.
But there has been nowhere near enough money available to do something like set up a pair of molniya orbit satellites with long apogee dwell times over the center of antarctica.
Assuming that the topology will be additional highly-inclined/polar orbit starlink satellites, communicating with each other in a laser chain, this will be dependent on starlink setting up earth stations near fiber somewhere in southern Chile, Argentina or in South Africa. Or south australia, tasmania, new zealand.
Now that I think about it though, the Starlink user terminals likely won't be able to survive the harsh winters at the poles. -30 deg C and low tolerance for high winds means this would be tough unless some type of non-obstructive sheltering could be provided.
Even if you maintained multiple $1.25 per minute (or $5 per megabyte) Iridium links, operating 24x7x365, it would be a teensy tiny drop in the bucket compared to the total budget of the station.
https://www.wolframalpha.com/input/?i=2*6300*arccos%286300%2...
I have seen no evidence that traders will be the primary users. Do you have any evidence or cases where they are doing or planning this. Are you just guessing?
Starlink gives them the same opportunity across Atlantic, Pacific, and Indian oceans. You can bet that there will be orbits that exactly link London and New York, New York and Tokyo, New York and Singapore, London and Singapore, etc. Traffic not sent under extra-high tariffs will be artificially delayed enough milliseconds to match fiber.
It would not be surprising if these low-latency contracts, for traffic amounting to well under 0.1% of total capacity, provide 10% of revenue.
It would also not be surprising if future satellites have tens of TB of storage onboard to proxy streaming for the highest-demand shows of the moment, and broadcast capability to multiple ground stations simultaneously for live streams, particularly soccer matches.
Most likely, aside from financial transaction data, routing will always offload packets to ground terminals as early as possible. I strongly doubt zigzag routing will happen at all.
Another may be gaming.
Another is as you say planes and ships out of reach of ground stations (very sparse situation however).
The financial upside is clear, but what kind of emergency capabilities do you mean?
But I too was interested to see if they had an actual idea in mind?
I would think the computer game market. Maybe other markets that have high end mature users where client side is very good so lower latency might be something that matters relative.
At some point, the communication has to enter the terrestrial network. That entry node is likely to be under the influence, if not outright control, of Five Eyes security infrastructure.
You would need to build out a lot of infrastructure to escape the sort of ubiquitous surveillance that is available to those organizations.
Not necessarily. If you're communicating between two SpaceX terminals, that could feasibly avoid SpaceX ground stations. I don't know how capable SpaceX's routing actually is to know if this is within their scope though.
If it's flying through the air and somebody really wants to grab it they will, whether they can read it depends on how good your crypto is.
LEO is far from a true vacuum. But it's sparse enough that you have limited beam scattering. Getting a read on a sat-to-sat laser emission from the ground is nontrivial.
That said, I imagine that for any serious bandwidth, you won't get enough SNR to decode anything from the ground.
I guess if you got an observation platform up closer that would help.
If they were strongly encrypted there may be no reason for a nation state to observe the intersatellite links, but I wouldn't expect this at least for the near future since Elon's focus will probably be to cut corners to get the absolute best performance possible.
[0] https://en.wikipedia.org/wiki/Consultative_Committee_for_Spa...
[1] https://www.google.com/search?q=ccsds+protocols&source=lnms&...
Edited to add: I'm not making any claims on what protocols Starlink uses specifically. Just describing the general approach.
In practical terms I don't think it's a major concern. Much more likely that the spy agencies would tap the lines coming out of the ground stations.
Which is a significant step backwards for e.g. Russia.
Currently, all data between Asia and North America runs on cables. Anybody can spy on those. If those data did satellite laser hops, only those with ground stations would have access. Everyone else gets locked out.
I have no doubt that (like every other geo-mobile satellite constellation) the system allows for "port mirroring" on point-to-point links, or (more likely) relays everything through a ground station even when doing so has performance implications. This allows them to fulfill their obligation to government(s) surveillance.
They can't (as far as I know) use beamforming with lasers, so they can't be steered to different terminals as quickly.
As the sister comment implies though, Starlink sats are in low Low-Earth-Orbit (LEO) so they experience non-zero drag from the atmosphere. This slows them down, causing them to gradually fall back to Earth, creating a natural expected service lifetime for each satellite in orbit.
So the expectation is that SpaceX will have to continually put up more and more replacements indefinitely as older sats decay and burn up in the atmosphere. These 10 laser sats are just the latest among a string of sats that are yet to come online with newer and better capabilities.
(downvotes don’t change facts, kiddos)
First, that the unit pricing was too high. SpaceX is targeting an extremely (absurdly) low price of $250,000 BOM per satelite, and it was theorized that the laser links were blowing the budget. Estimated that it would cost ~$100k for the lasers, targeting, and electrical systems to add the links.
Second, I've read that they had issues guaranteeing that all the components of the laser system would fully burn up in the atmosphere. One of the conditions of launching low-orbit satellites is that they will fully burn up on re-entry (therefore not posing any risk when they fall back down to earth). Apparently some of the optics components had a chance of survival and ultimately possible land-impact.
I'm not sure if we can say that this launch indicates that the cost issue has been solved. It could be worth blowing out the BOM to get some operational experience having a few birds with the lasers, so perhaps they haven't fully solved the pricing issue unless we start seeing lasers on every subsequent launch.
TFA has a great animation of a polar orbit. It's basically a longitudinal orbit, so it will absolutely pass over land for a lot of the time, so clearly they must have at least solved the burn-up issue, if in fact that actually was ever an issue in the first place.
Also, FYI, there was a scheduled attempt to launch SN9 today, but it just got scrubbed a minute ago due to winds. They will be trying again tomorrow! reddit.com/r/spacex is a good place to watch for updates: https://www.reddit.com/r/spacex/comments/krllbt/starship_sn9...
Lots of good reasons they just launched before the laser links were ready. Also, they don’t necessarily need them except for really, REALLY remote customers (ie a minority), so they can sprinkle in lasers into their constellation as they become available.
I've seen the "burn up in the atmosphere" constraint before, and it struck me as a bit crazy for Shoot First and Ask Questions Later SpaceX to care about this
SpaceX has never been even a little careless about following laws, regulations and staying within the lines of their FCC/FAA authorizations. There is this reputation surrounding them, probably because of their visible and often explosive development practices, an because Tesla absolutely does play fast and loose with regulations, but for SpaceX it is not just entirely baseless, it's sort of the exact opposite of the truth.
When FCC tells SpaceX to jump, SpaceX asks how high on the way up. Demisability standards were among the constraints of their license, so SpaceX made sure to not just meet the requirements, but well exceed them, which is what they always do.
Why Musk likes to flout all rules at Tesla and yet follows rules strictly at SpaceX probably as a lot to do with how the regulators are generally pretty toothless about doing anything to Tesla, while either the FCC or the FAA could pretty much shut SpaceX down for as long as they like should SpaceX try to play cute with them. Enforcers with actual ability to enforce rules tend to be respected more.
No. You have been misinformed, they have always asked for the authorization first. For the orbit modification to 550km, they asked on 2018-11-08, were granted permission on 2019-04-26, and started launching a month after that. [0][1]
[0]: https://fcc.report/IBFS/SAT-MOD-20181108-00083 [1]: https://en.wikipedia.org/wiki/Starlink#Launches
I would rather go with FCC's interpretation on this, rather than competing commercial entities who have a vested interest in one outcome. If FCC didn't like the amendment, they could have just said no.
> You say it's fair, but certainly if you were in that industry as a competitor it appears as favoritism.
No they didn't. When this was publicly said by a competitor when the challenge to the amendment was filed, and exasperated FCC official literally said publicly that anyone is, and has always been, able to do things the way that SpaceX is doing, and in fact FCC prefers it. The only reason most companies have not been doing it this way in the past is that SpaceX ends up paying a lot more in filing fees. The argument that SpaceX doing this is somehow favoritism is harebrained. What exactly is stopping the competitors from doing the same?
Whether it's fair or not is also entirely beside the point. That was not what I was arguing at all.
> They also lie to push things through, like rate of decay, speeds offered, latency.
No, they don't. The rate of decay calculations in SpaceX filings have been based on the models FCC expects licensees to use. Yes, they do not perfectly model reality, but they are what FCC wants, and what everyone else uses too. As for speeds offered and latency, well, actual latency as realized in the beta seems well in line with what SpaceX has promised, and while they so far only offer a single speed grade to beta testers, they have demonstrated speeds in line with their original claims to the air force, and presumably will also offer those to customers (at a much higher price point) some point in the future. This is also entirely beside the point.
To be frank, right now you sound like you have read too many dishonest SpaceX hitpieces, synthesized the idea that SpaceX is ran by cowboys who habitually ignore the rules, and are grasping at straws to support it, including quite a bit of moving the goalposts.
I have made a single, factual claim: SpaceX meticulously follows the rulings given out by FCC and FAA. I spend quite a lot of time spelunking FCC filings looking for information about satellites, and I honestly believe it to be true. Can you point to a single actual counterexample? Not "competitor is angry about FCC ruling and claims FCC shouldn't have done something", but an actual FCC ruling or regulation on the books, that SpaceX proceeded to break. Because I do not know of a single example, and that is actually rare for a company in the industry. If you believe such an example to exist, please post it, preferably with a link to the actual ruling they are breaking.
To be frank, it sounds like you don't understand the industry very well, and that's ok. But not everyone forgets what was said in 2015 when the project was launching. Since you asked, here's one non-truth:
https://licensing.fcc.gov/myibfs/download.do?attachment_key=...
>High capacity: Each satellite in the SpaceX System provides aggregate downlink capacity to users ranging from 17 to 23 Gbps, depending on the gain of the user terminal involved. Assuming an average of 20 Gbps, the 1600 satellites in the Initial Deployment would have a total aggregate capacity of 32 Tbps. SpaceX will periodically improve the satellites over the course of the multi-year deployment of the system, which may further increase capacity.
This ignores A) competitors who have first priority on the spectrum, B) 80% of the satellites are over water and completely unusable during that time, and C) more recently we know that the user terminal at best would perform lower than the 17Gbps low end they cite due to cost-cutting on the scan and G/T of the antenna.
If you believe it's okay to lie in FCC filings so that you win awards and change policies, then that's a valid opinion to hold.
No I didn't. I specifically asked for an FCC or FAA reg that SpaceX has broken. This is a very different thing.
> If you believe it's okay to lie in FCC filings so that you win awards and change policies, then that's a valid opinion to hold.
That's not an opinion I have, and I don't actually believe your claims about them lying are correct here (you seem to assume that FCC is composed of idiots), but regardless, it's completely irrelevant to the point. Even if they do that, my point that once FCC or FAA puts something official on paper, SpaceX treats the words as holy, remains.
Look back at the beginning of this thread. Someone made a statement that can be boiled down to "SpaceX ignores FCC regs". They do not do that. My entire, and only, point here was that they do not do that. You apparently seemed to take that as a "SpaceX is good" statement, and have argued against it with essentially entirely random "SpaceX is bad" statements. How the f is the failure rate of SpaceX satellites even remotely connected to anything here? Or did you just jump to it because you wanted to say something negative about SpaceX.
So I ask again: Do you know of a single case where SpaceX broke or ignored FCC regs? Not things where they did something you think as bad, but where there was a rule, and they broke it. That's a simple question.
https://docs.fcc.gov/public/attachments/DA-21-34A1.pdf
Note that SpaceX asked for more, but FCC decided to only grant 10 satellites for now. So, SpaceX did as they always do and followed the order to the letter, and only deployed 10.
Plus, the last thing SpaceX wants is a news story about killer satellites raining debris on innocent citizens. Remember that each satellite launched has to be deorbited eventually, so if they're launching dozens of sats per month they'll eventually be deorbiting dozens of sats per month. If they don't fully burn up each one will have a chance of hitting someone. Sure the chance may be very small, but when you're rolling the dice dozens or hundreds of times per month eventually you're going to land on snake eyes.
Note - despite other posters claims, this is not a requirement and there are other approaches as well for the safety side here. The most common is to deorbit into the ocean (the sats are maneuverable) with a failure rate and part hazard rate low enough that remaining risk is minimized. I would expect they would deorbit into ocean / near non-populated areas for other reasons as well.
> The laser terminals supplied by Tesat needed less than 25 seconds on average to lock onto each other and begin transmission in both directions at 5.6 Gbit/s.
https://www.laserfocusworld.com/lasers-sources/article/14104...
Napkin math: that’s 56 clients using constant 100 MBit/sec. With overbooking coefficient of 0.01, that’s 5,600 clients on 100 MBit/sec plan per sattelite with 1 MBit/sec guranteed.
All I know about them is that a reason they weren't deployed in the first batches of satellites is their original design included parts that did not burn up completely on reentry, and SpaceX wants Starlink satellites to always burn up completely, since there are thousands of them.
...however, this is nowhere near any fundamental limit on optical transmission. SpaceX is operating around 20-40GHz radios, and let’s just say a bandwidth 1% of the frequency with a SNR of 1, giving them a bit rate per channel of 200-400Megabits/s. The same calculation with near IR optical (which is optimistic obviously) gives 3 Petahertz frequency, 30THz bandwidth, and 30terabits/s/channel. So optical is nowhere near any kind of fundamental limit, unlike radio which needs many channels (ie phased array, MIMO, spatial multiplexing generally, etc) to saturate the bandwidth of the satellite bus.
(Also, note that broadband users have a capacity factor of like 1-2%, so on average 20Gbps can give service to like 10,000 subscribers per viewable satellite using 100Mbps peak service.)
The radio encoding schemes are more efficient in a bits per Hz-of-EM-spectrum sense, but optical systems have the advantage of being at such a high frequencies that even "inefficient" coding schemes can reach very useful datarates.
I have always been amazed at how satellites quote bandwidths on the order of Tb/s, when I don't fundamentally see how they're so different from gigabit fiber, copper, etc. You've still got some oscillation going on and a receiver that has to "decode" it just the same.
Is there a physically intuitive way to understand why the bandwidth of these methods is so great?
> Each satellite in the SpaceX System provides aggregate downlink capacity to users ranging from 17 to 23 Gbps, depending on the gain of the user terminal involved. Assuming an average of 20 Gbps, the 1600 satellites in the Initial Deployment would have a total aggregate capacity of 32 Tbps.
https://fcc.report/IBFS/SAT-LOA-20161115-00118/1158349
They have a couple of GHz of bandwidth on the satellites for each of the user downlinks/ground station uplinks, and maybe a GHz for the user uplinks/ground station downlinks, operating in the Ku (12-18 GHz) and Ku (27-40 GHz) bands (requested frequencies on page 8 of the linked paper.)
Higher SNR means lower bit error rate means deeper modulation (cutting edge is like 65536-QAM and maybe higher). Noisy channel coding theorem and all that.
I think it is unlikely that we will see data centers in space unless it is absolutely unavoidable, e.g. because of lag between Earth and the place (in space) where the data is needed.
A CDN sending or storing their consumer facing data via satellite makes no sense. But control plane data? Maybe.
Cut 30 ms off of SF to NYC and how you manage consensus might change quite a bit.
Put the global (no longer replicated) datastore in space, and let me run some simple Lambda functions. Low latency, atomic transactions from anywhere in the world! Yes please!
I can see running HSMs in space; probably the most cost-effective physical security available.
This is actively being worked on in the research community, excited to see if it comes to fruition.
> There may be some ground stations owned by WISPs or whatever servicing a whole community
I'm talking about the ground stations that provide internet access to the satellites.
> all streaming the same new Cobra Kai episode
Multicast it.
So you were trying to say what exactly?
I would pay a 4x multiple to be able to dump my own money in here... sadly, I am not a billionaire, and have no access to this market.
Maybe, maybe not. None of these things have proven to have a profitable business model, so how are deriving the value?
Of course, if that doesn't matter to you, there are myriad ways to hand your money over to SpaceX.
SpaceX has wildly bigger upside if the big bets pay off.
Because SpaceX is a private company, none of us really know (publicly) its financial state. It could be profitable at this point.
But of course you can finance Starlink and continue to be, so that part is VC funded.
And they have not received FCC money yet.
This article is from 2017, since then they have done a lot better.
SpaceX always reinvested every penny into development and they have done so for a long time.
Taking a loan, or investment, does not suddenly make a company unprofitable, that would be a silly way of looking at the world.
I don't have any figures for SpaceX, but I suspect the amount of cash they've be able to raise relates directly to the expected future value of the company. That they're able to launch 60 satellites at once for a fraction of the cost of other launch companies probably helps.
Part of the reason I asked what you meant by profitable is that you seem to be conflating operating and capital expenses.
From the perspective of the 'launch-arm' of SpaceX, launch costs are operational expenses and profitability analysis will typically balance that against payment for the service provided.
From the perspective of the 'starlink-arm' of SpaceX, launch costs are capital expenses and should be accounted for by depreciating the cost over the life of the asset (the satellites).
If you want to look at the profitability across the entire business then you have to be very specific about what you're measuring, and clear what you mean when you say profitable - at least if you want your analysis to be useful.
Also worth noting that the article is about data from 2015, which was the first year they had ever landed an orbital-class booster (Falcon 9), and only the one time (in December 2015). The first time they ever re-used a booster for a customer payload was in 2017 (after the WSJ article you cite was published). Since then they've re-used boosters many times, with their recent launch actually being the 8th launch+recovery of the same booster. So what was iffy/nascent in 2015/2017 is now proven/consistent in 2021. They are doing much, much better from when that article as published.
Also are we looking at the same chart? Not sure how you can make the claim that the number of launches has been dropping every year... every year since when? 2020 was the most launches ever, and in 2021 they are expected to do more commercial customer launches than all launches in 2020 + Starlink launches on top of that.
and remove all launches where SpaceX was the customer (a net loss unless the payload they launch has payoff), and specifically look at the GTO launches (the ones that pay the most money). There are fewer and fewer GTO launches, and the number of customers has been going down. A cursory glance shows 2017 had 8, 8 in 2018, 4 in 2019, 2 in 2020, and about 8 planned in 2021 (we'll see, these typically slip quite a bit. The point being that they need profitable launches (not a small satellite they rideshare with 10 starlinks on) to sustain a launch business with that many engineers on it. I think 2021 will launch maybe half the GTO/GEO they're targeting this year due to delays, as was the case in 2020.
Regardless, commercial launches is what I was talking about as well. Do you have a reference for the idea that GTO launches are the only ones which are profitable / significantly more profitable than other launches? I haven't seen that. Because otherwise it seems pretty out there to only look at a small subset of their commercial launches.
And I'm assuming they'll do more GTO launches once Starship + Superheavy is online.
It's a 6x difference in cost per kg.
Alphabet owns a reasonable chuck of spaceX, which is the easiest to way to gain exposure.
In a pre-IPO company, VCs and other investment groups consider unaccredited investors to be a liability, and they'll either give worse terms or no terms. If you're worth a million bucks the SEC considers you to be a grown-up and that you'll ask questions rather than being spoon-fed data that can help you protect your investment, which takes away a bunch of scenarios where you can litigate.
I worked at a company that turned out to have an unaccredited investor. I didn't hear the details but they had to 'fix it' before the VCs would move forward with discussions. (They still didn't get the money.)
GP's implication is that if you have a million bucks you can get (are?) accredited, which will give you access to private shares. I've heard this too, but I couldn't tell you the details.
FundersClub and AngelList are more executive-focussed sites, aren't they?
That would be a better product for the traditional GEO comsat operators, but apparently there's not enough market there for them to bother. NASA already has a system for that, TDRS. I wonder how busy it is nowadays?
last time i had anything to do with TDRSS (circa 2013), it was extremely busy, expensive, and it was the military that got the high bandwidth links. we could only use it to communicate with our research spacecraft during early orbit activities, or emergencies. and we got something like 2400 to 9600bps.
Competition for use is still strong. We tend to get a few hour-ish chunks every day and it varies a lot.
(EDIT: Just realiesd if I'd waited a few hours to post, then I could say that this came via TDRSS ;)
More info: https://www.usap.gov/technology/contentHandler.cfm?id=1971
> For a fee, commercial users can also have access to TDRSS for tracking and data acquisition purposes.
This comes from a rulemaking that updated the regulation. See: https://www.federalregister.gov/documents/2012/02/10/2012-26...
See the actual active regulation at 14 CFR 1215.
SpaceX/Elon hasn't gone into a huge amount of detail about what's involved in refurbishing the first stage. I imagine a lot of it comes down to inspecting parts and making sure they haven't been damaged or worn out, and replacing the ones that have. Maybe cleaning out soot from the engines. The stated goal is to not have to do any inspection or refurbishment between flights, but they aren't there yet.
https://twitter.com/elonmusk/status/1143195449425321984 https://twitter.com/elonmusk/status/1313450351366873090
Exploding rockets ruin their day, disappoint customers, and endanger any people onboard.
https://twitter.com/wikkit/status/1353354797127245825
https://twitter.com/RDAnglePhoto/status/1353764105040093186?...
Translation for all beltalowda: “Bossmang say each satellite have a tightbeam”
Way OT, but the patois/creole used by the Belters is well done, too.
This actress (Cara Gee) in "real life": https://youtu.be/f20fkrf1d5A?t=101
It is "good physics" the same way _The Martian_ is good physics. Neither is actually close....but they're far better than you see in Battlestar Galactica.
I don't remember too many glaring examples from The Expanse either. They generally have artificial gravity when under thrust and not when they don't. When slowing down, they generally have the engines pointed towards the thing they're approaching. The characters in high-G maneuvers don't look the way people would actually look in those situations, but that's hard to fake without actually sticking actors in a centrifuge so I'm willing to give them a pass.
Scientific accuracy isn't really the focus of the show, though. It's a show set in space that needs reasonably accurate physics in order to have a plausible setting and not detract from the the story and the characters.
Do you know of other fiction that does it better?
SpaceX places Starlink satellites in polar orbit.