They're not pushing for this, I'm not aware any filing or meeting with FCC that's aimed to raise this limit. I think the reason is even if they increase F9 cadence by 50% every year, it'd be a while before they hit the limit, especially given some old Gen1 satellites may start to retire in the next year or two.
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Starshield has an Earth observation component in it, it's been known since it's unveiled a year ago, you can see this on its official page: SpaceX - Starshield, it's not a secret.
China is spying on the US too, yet the US still allow China to sell its products here.
SpaceX to let other satellite providers piggy back via laser links
I'd guess back haul. I imagine imaging satellite companies would love a huge boost in available download capacity.
I'd guess multiple sensors--visible light imaging for sure, but also thermal (probably fast tracking--like following a missile), maybe specific elements/gasses, sensors to track other satellites... Almost surely The Establishment is building all of them (Raytheon, L3 Harris, etc.), which is how they historically run programs. The latest SDA activity is a great example where the commercial entities (York, Maxar, Rocket Lab) are providing the platforms, but the actual payloads are government furnished. (DARPA's blackjack is similar) SX doesn't actually have the expertise to do this kind of equipment either and really there's not a ton of upside in them building out the in-house capability. The Man isn't going to sole source an entire satellite (including equipment) from anyone let alone SX, and the business model really doesn't align with SX's general direction (low volume, exquisite design, long schedule, heavy customer involvement).
Intra constellation comms isn't a common application--there's really not a lot of 'talking' one sat has to do to another sat within a constellation. Most of processing/communication really happens at the constellation level, and it's still overall far more efficient to keep that level of mission management on the ground. So...ISLs just carry the 'backhaul' traffic, be it user data or cmd/tlm packets.
It's not clear to me the use case here (I can't see the article or the twitter replies) so I don't know if they're offering a service to link your non-starlink sat to a starlink sat, or whether the'll sell you a constellation's worth of ISLs to put on your junk (or both?). In either case SX ISL's have some unfavorable characteristics (short range, low radiation tolerance) so that does limit a bit the market. Basically, a service ISL sat needs to be close to the starlink constellation (in both altitude and inclination), and an infrastructure level sale requires a constellation that is both massive and low in altitude.
That's not to say there's no upside--plugging into the Starlink ISL network as a service, for instance, could theoretically enable a customer to abstract away all (or at least most) of their ground infrastructure while also getting constant communication. Maybe such a scenario keeps a T&C center hot in the event the ISL network is down (could just be Ksat time?), but otherwise the 'Ops center' is just some person's laptop.
Appreciate the link supporting my assertion. Polaris Dawn is going to be geometrically compatible with Starlink and VERY short mission life.
How does
High Altitude [1,400km]
This Dragon mission will take advantage of Falcon 9 and Dragon’s maximum performance, flying higher than any Dragon mission to date and endeavoring to reach the highest Earth orbit ever flown. Orbiting through portions of the Van Allen radiation belt, Polaris Dawn will conduct research with the aim of better understanding the effects of spaceflight and space radiation on human health.support
Fault? Not at all. I'm simply asking for a source with information on Starlink ISL having short range and/or low radiation tolerance since this is the first I am hearing of this.
Indeed.
All of Starlink was designed on the edge of radiation tolerance. They pushing the limits across the board on everything (not just radiation tolerance), and they don't waste time/effort/money/resources on margin. They only spend money on uprated/radhard EEE parts where it's absolutely necessary. That logic is a major reason the constellation is so inexpensive, and is also why they don't have an official, public domain number for satellite life.
For Polaris Dawn, being both a) a non mission critical experiment and b) a total mission life measured in days (Vs years), radiation tolerance is largely a non-issue, obviously in total dose, but also relative to things like SEUs.
Starlink ISLs were designed to operate in the Starlink constellation that has with historically short range due to the historically high shell density. That design space results in a much easier optical solution than something that needs to operate over much longer distances. Like everything else SX does, they do not built things bigger/better than they need to be because that's a waste of time/money.
The biggest impacts range has on the unit is 1) pointing (as a function of motor steps) and 2) throughput. For Polaris Dawn, being both a) a non mission critical experiment and b) something that doesn't have hard/stringent throughput requirements, the Starlink ISL, absent some more detailed operational parameters, will likely work just fine.
Starlink's Laser System Is Beaming 42 Million GB of Data Per Day
A SpaceX engineer details how the company is using a fleet of 9,000 lasers over the Starlink constellation to deliver high-speed internet across the globe.
That's not short range at all, and the link is only broken because it's dipping very low into the atmosphere.
It's funny to me how we use ambiguous characterizations like "short" and then argue forever about it in those terms. Is 5,400 km short? To a ditch digger, no. To an interstellar traveler, yes. To satellite communications? I'm glad to see a number dropped in here.
I would expect similar... imaging subsystems with these requirements would seem to be a low-volume/high-price type of thing, and that's not really SX's bread and butter.
Yeah, I was thinking that the "intra constellation" application would be more along the lines of Starlink sats being used to allow sats within a constellation to "relay" data from one to another if their density wasn't sufficient to do it themselves. While there may not be a lot of need to do that today, that might be because a reliable constellation with enough density and ISL's didn't previously exist, and it might not be feasible to do it if you only have a few spy sats or what have you.
What novel applications can you have if you have half a dozen sats with sensors that can cooperate directly? I dunno.. maybe nothing you couldn't do with ground-stations, but avoiding that as a requirement may be advantageous...
That's to be expected. It's not like we're talking an order of magnitude difference between that extreme case and the operating case. The Starlink ISL's were designed to work with distances in the ~2000km (and shorter) range and I think everyone would be surprised if they couldn't close the link at 5400km (of course with reduced link quality and throughput). That doesn't change the reality that SX designed their ISLs to work at short ranges rather than "typical" LEO ranges that you'd find with other "big" constellations (Iritium, Telesat, Oneweb); that's explicitly because the unprecedented density of the starlink constellation plus its low altitude and short life span meant they didn't have to build a more exquisite piece of equipment like, for instance, Telesat has to procure.
(And of course, the Telesat ISLs cost at least 10x if not much more than a Starlink ISL.)
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Yep. SX could build out internal capability and get into (for instance) the optical/SAR imaging game. They could try to leverage their brand (high volume, low exquisite-ness, fast iterations), but...that's not really where the money is in imaging. Planet has made a decent go at low-res imaging with their gazillion cubesats, but the real money starts in the sub-meter realm, and even then it's not really been a boon, as evidence by the various players in that space that are all more or less scraping by. You have to go to high res stuff to find a real cash cow business case (like Digital Globe/Maxar), and then you're spending tens of millions per sat to get the exquisite performance in satellite control and resolution. For some bench racing, the Worldview Legion sats are somewhere in the $20-40M range, including a $10M (or more?) Raytheon telescope on them (that's got decades of design heritage in Black Space...), a couple of million dollar star trackers, and CMG's that can snap the thing around at 30 deg/second and stop on a dime with full compliance, while returning probably 20cm resolution. (They say "sub 30cm"...)
Ah, yeah. If you're hooking your satellites into the starlink ISL network then presumably they don't otherwise have the ability to comm with each other. However, I'd still imagine that any comm from Sat A gets "internet-ized" and then sort of vanishes into the starlink traffic before being routed back out to Sat B. Presumably if A and B are physically close the Starlink Routing Overlord Machine would decide that the smartest way to get that packet moved is to just hop through starlink sats and then back out to B, but I could also imagine the packet also getting routed on the ground for some part of its abstract journey from A to B.
It's certainly fair to contemplate applications through the lens of The Future; its certainly reasonable to assume there will be use cases that we aren't smart enough to think about yet.
Today, there are sciencey missions that have some coupling of multiple satellites...but also there's no money in science so that's not exactly a market. Also the necessary coupling is more things like ultra fidelity ranging/sensing rather than data transmission. (How close is that other satellite, what is the atmospheric composition between us, etc.)
One could imagine heavy processing on a satellite...servers, mining (Blockchain!!!), etc...but even then intra-constellation comms still feels like the relay flavor rather than the cooperation flavor. One application I can think of here is imaging data, and the problem being solved is the size of the pipe to the ground: To varying degrees, [some] imaging sats on orbit do some level of image processing prior to beaming to the ground. It's mostly throwing out bad data and the like, but some do a little more post-processing depending on the request. I could imagine a future where a significantly higher amount of data than is collected today might benefit from significantly higher degree of processing, where you really want to start being really cognizant of what you're trying to squeeze into the ground link pipe. Add on potential desire to have a fast timeline between shooting the target and resolving that data into an action and local or near local computing might be useful (like if the next door sat is some big processing machine). We're still just talking data between sats at that point, but potentially much better enabled by keeping activity to the 'neighborhood' level rather than some terrestrial mothership.
One could also imagine some kind of autonomous defense application--Blackjack is kind of like a baby step there, and tying into above, at one point DARPA was very interested in using the Telesat light speed platform for Blackjack. The SDA activity is similar, where there will be multiple flavor of satellites in the constellation with various objectives, and there's some degree of on-orbit processing and "sharing of findings" amongst the satellites without ground intervention. Obviously there's no final action contemplated in those autonomous systems (and hopefully there never is...), but certainly/hopefully building a system that brings only useful data to The Deciders is going to be more efficient and accurate.
Relative to your thread pulling, the irony in the advent of optical ISLs (SDA now calls them OCT because--I assume--they needed a new acronym for a thing that already exists) is that the significant throughput and constant access to all the constellation nodes they enable sort of minimizes the need for satellites themselves to have massive on board processing capability or the ability to have significant PTP comms with their neighbors. It really just does become a problem about the size of the ground link pipe.
Actually all of these are speculation, I provided my source, it's your turn.
BTW Iridium doesn't use optical ISL, they use Ka band radio ISL. OneWeb Gen1 doesn't use ISL at all.
Yeah?
What I've said boils down to: In approaching the ISL design space, SX followed their well established (and oft lauded, especially here) practice of not over designing, over speccing, or over building the equipment. SX only creates a thing to do what it needs to do rather than take the legacy space industry approach of building in tons of margin and conservatism, and SX continued that practice with their ISLs.
As for your "source", again, that not evidence of anything other than the fact that SX can build an ISL that works. (Indeed a difficult job if there ever was one, as evidence by the troubles they had getting the ISL design locked down). Like your mobile phone that isn't designed to operate efficiently over many tens of miles, the starlink ISLs were not designed to operate over typical LEO distances. Like your mobile phone that will still actually work over tens of miles with clear line of sight, the Starlink ISLs work over much longer distances than to the space in which they were intended to operate.
If you really want to talk about sources, how about you provide one that says, despite the mountain of evidence to the contrary, for basically anything that SX has ever done, that SX rejected their core competency of First Principals problem solving and instead designed their ISL to be WAY more capable than what the Starlink constellation needs.
Sure. I didn't suggest otherwise. I offered those constellations as examples of representative (and real) "big" constellations that fly at higher altitudes and with much lower density than Starlink, and thus have significantly larger distances between satellites and a much harsher radiation environment. You'll notice that I didn't put Kuiper on that list; the reason is because it is much closer in altitude and quantity to Starlink and, near as makes no difference for the point, in the same design space for ISLs.
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