But at the altitude the satellites (will) operate, that adds about 8ms delay (round trip for satellite immediately above, might be slightly worse). In contrast, the fastest round-trip to a geostationary sat is 233ms. That's a big improvement.
About 50% faster if the speed of light in fibre is 2c/3.
If you transmitted data straight up 700 miles, and then around the constellation all at 700 miles elevation, and then back down 700 miles, it would need to go 16165 miles (700*2 + 2pi4700/2) @ 187,000 miles per second (1c), or take 0.086 seconds.
This seems like pretty exciting stuff.
In the end it is probably mostly a matter of how many hops that will determine which is the faster path, the two paths are mostly equal in other respects, I suspect the latency incurred for each hop is roughly the same, assuming they use error correction and re-transmission on the link layers between the satellites.
If it all gets passed through blindly then it will be a bit quicker because there is no decoding step involved but I highly doubt that because it would lead to substantial inefficiencies and loss of capacity (the difference between a switched and hub). Smarter to be a bit slower and to maximize the routing capabilities of the satellites so as to optimize for the scarce resource: inter-satellite bandwidth.
I'm quite curious to see what their antenna setup looks like in practice that's going to be an engineering marvel.
But optical signal amplification is a trick that really only works when you are on a very long run where the signal gets attenuated to the point that you need to boost it. There is no routing option in such a system, it is essentially point-to-point with in-line amplifiers.
So even if they may use laser based comms I don't think optical amplification will be used, the more likely avenue is to decode the optical signal, decide where it has to go next and then fire off another burst.
Alternatively they may use radio waves instead of lasers, I'm not sure what system SpaceX will use for this particular system, given the accuracy required for laser based communications I would assume they will use radio.
We were planning on tracking satellites in adjacent orbital planes (which were orbiting in the opposite direction) as well as in-plane. So, yeah, moving parts.
Whenever this topic comes up, I wonder what happened to all the work we did at Motorola in 98-99. There were several hundred engineers in Tempe generating thousands of pages of design documents for over a year. We archived all our work in spring 1999 sand were all shuffled off to other projects.
Presuming a flat surface of 200 X 200, and a random line across half of that, and presuming that satellites only communicate with nearest neighbours you can guesstimate that the extra distance is significant (ignoring other factors).
If they can communicate with more distant satellites then distance could decrease (short cut segments around great circle).
Since the earth is 6,378 km in radius, adding another 1,150 km only makes the circumference about 18% longer.
In fact, the SpaceX proposal looks a lot like the Iridium concept in general, but with thousands of little satellites instead of dozens of larger ones (which probably makes the implementation very different).
Which one to buy !
- Hawaii (Military only)
and then it is routed through the fibre backbone.
With the SpaceX proposal there will be more ground egress points, so it will be able to get closer to the destination before grounding.
SpaceX's 2 test satellites were 400 kg.
The concept 'Size, Weight, and Power' (SWaP) is commonly used when comparing FSO vs. RF systems. Incidentally, FSO systems have lower SWaP than RF systems. They're smaller and lighter payloads, and the system requires less poweR.
Hopefully the telecoms market has changed enough since then (cf Iridium's recent profitability, even while launching a whole new constellation) to make it suddenly viable.
SpaceX's network seems to work the other way around by being designed around fast-moving satellites and complex ground terminals that do the tracking and hand-overs by means of phase array antennas (ie. completely solid-state). In comparison to Inmarsat it is not GEO-bounce and in comparison to Iridium they seem to have some solution for having fully connected mesh of satellites (original Iridium is not fully connected sphere as there isn't even attempt to have link between satellites with oposite orbits)
...and a whole bunch of other players. So competition is definitely a thing.
In fact, SpaceX is actually really behind on this. http://www.oneweb.world/ actually has sats built now and are building the rest of the constellation now.
So SpaceX will not be alone if they actually manage to build a constellation. Also, the Iridium next constellation is half way up and running. Which is technically a LEO constellation that can provide internet.
Probably good for airline inflight WiFi too.
In the world of physical fiber connectivity, a "mere miles" could be anything from 100s of thousands of dollars to millions of dollars worth of investment to connect you. Unfortunately. It would only make sense for them to provide service in your area if the infrastructure already exists or there is enough population density to make service profitable.
For everybody else below that, it's a revolution in access. If you're in Brazil, Colombia or Argentina where the average is around 5-8mbps, this could be a huge change if the price is close enough to what their markets can bear. It should help all of these nations leap over the need to build out very expensive national fiber to the premises systems.
People are a little over-excited about the possibilities of this network - even with the huge number of satellites they have, if you’re in a densely populated area you could still be sharing a spot beam with 100k to many hundreds of thousands of people. Now, even if they had a ridiculously good 1Tbps per spot beam (currently there are satellites that can do that much throughout for the whole thing but in reality you’d probably be both power- and RF spextrum-constrained).
So at 100k subscribers you’re down to about 15Mbps per subscriber (being really generous), so you’re talking about on average, best case in suburban areas having a 50-60Mbps service. In metro probably more like 10 theoretically (and potentially an order of magnitude less in reality with decent take up rate)...
This kind of speed is already fairly common in Australia in metro/suburban areas (I have 100/40Mbps) and LTE is generally is even faster but the quotas really small (I have 12Gbps a month on LTE but 1Tb on my cable).
The main problem for this kind of internet in Australia is that we have some of the highest urbanisation in the world (which actually makes it easy to run fixed line services like FTTH to 80% or so of our population - our problems have been almost entirely a failed Government privatisation of our monopoly telco (which turned them into a single, huge, anticompetitive private monopoly) and then a change of Government watering down a Government-run last mile network that was in early construction that private retailers would sell services over on an open-access basis (changing to obsolete technology like FTTN from FTTH on ideological grounds to cripple it)).
So we don’t have as much as the market in the semi-rural kind of density which is where Spacex’s idea would really shine.
Also, I presume Spacex and others will be significantly over subscribing their ‘pipes’. They can take huge advantage of selling the same pipe to business and home users, with different time-of-day use profiles. So you can double or triple or even 10x the number of customers (or available link speed!) in your assumption, all paying $50-$150/mo, since most connections are dormant most of the time. I’m sure we will see simple mechanisms to push the heaviest users back to landline connections, like data caps.
I have toyed with the idea of launching a WISP in Memphis TN area. The city has good cell tower build out, a surprisingly robust dark fiber network, and a few tall and evenly distributed high rises that could to provide great coverage. I was scared away due to the ability of incumbents to our-market me 100-1, and (illegally) dump their services on the market. However, the nail in the coffin for me was the announcement and progression of SpaceX’s internet plans. Sat based internet service is a beautiful business plan if you can control your launch costs and get latency down. Spacex has a high probability of getting it done.
But to your broader point, it does increasingly become difficult to live somewhere without good Internet. I know people, including in tech, who manage with just satellite but it means largely doing without a lot of things that many increasingly take for granted like streaming video and music and being generally careful about large downloads. (Bandwidth/data caps is probably a bigger issue than latency in general.) 5G will help too.
And it better not be trite. If they don't launch half the constellation (~2000 out of ~4000) within 6 years, then they lose their radiofrequency license.
So maybe by 2030 (2018+2*6) this plan will be executed. Let's hope so!
Another poster said their test satellites were 400kg, and the falcon 9 can hoist 22,800kg to LEO according to Wikipedia. That gives a ratio of 57 satellites per Falcon 9. The final satellite design might be heavier or lighter, the desired orbit may require more fuel and less payload, the satellites may require some additional hardware for securely storing and deploying them, and the current F9 may be superseded by bigger or more efficient or cheaper per payload kg rockets over the course of the next few years, so 70 per launch is probably a good guess to within an order of magnitude.
If they wait for the BFR, that (also according to Wikipedia) has a projected payload to LEO of 150,000kg or 375 test-satellite-equivalent masses. If it's cheaper per kg, they might just use that.
To minimize costs, I think it makes more sense for them to do RTLS than barge landings, especially as barge landings put hard limits on launch frequency (the barges aren't very fast).
However, even that 13,000kg is probably too high, because that is to an orbit that is probably lower than the 1150-1300km ones they are going to use for this.
However, for practical reasons enlarging the fairings can be more expensive than just flying more, so the limit of satellites per launch is probably set by how many they can fit into the standard F9 payload fairing. (1).
> If they wait for the BFR
They can't wait for very long, or they might lose their spectrum allocation. The contract requires them to put up half of their constellation in 6 years.
(1) page 36 of: http://www.spacex.com/sites/spacex/files/falcon_9_users_guid...
People are currently think they can send more then 10-20 on one flight.
Starting with the launch of Bangabandhu-1 on top of the B1046 core on 24th of this month, SpaceX will start launching satellites on top of the new Block 5 versions of their boosters. They are not designed to be reused once or twice with teardowns that approximate what was done with the Shuttles between the launches, they are designed to be reused "many" times, with refits every 10th launch.
What blows my mind about SpaceX is not just that costs are going to come down, it's just how much the worldwide space launch capacity is going to go up when they continue mass-producing rockets without discarding them, growing their fleet of launchers by ~1 every two months. (Factoring in the customers who want the performance of flying expendable).
Now the only thing I can think of is their new nukes.
Falcon 9 payload to LOE is 22,800kg.
Of course, the high payload of the boosters and the low weight of a single satellite in this constellation will mean that SpaceX will launch a lot of them per one rocket.
Certainly that could be done in theory - but the amount of energy it would take would be of a scale we haven't even begun to barely imagine. We certainly aren't generating that amount to do it, or harnessing such amount either.
So practically, the answer to your question is "no"; what we "send away" from the Earth is negligible.
In order for you to understand why, I encourage you to research the scale of things you are trying to understand. The Earth is big - really big. It may not seem like it, but it really is. What might cause you both a bit of "fright" and "wonder" though is the atmosphere: Compared to the Earth, the atmosphere is thin - very thin. For instance, if you imagined a baseball as the planet Earth, the atmosphere would be a very thin layer over the surface of the baseball, much lower than the ridges formed by the lacings.
Then you compare the scale of the Earth (it's size) to that of say - Jupiter (heck, just the Great Red Spot!). Then compare Jupiter's size to the size of the Sun (hint: Jupiter is tiny).
Then compare the Sun to the size of our nearest neighboring star. Then compare the size of that to other known stars.
Eventually you get to the size of our galaxy - which is an insanely large collection of stars...
Then take a look at the Hubble Deep Space image - and realize that all of those points, far in the background - that all of those are each a galaxy, separated by vast distances from each other...
...and then realize that what we see on that image is only a tiny amount of the whole universe.
The Earth? Compared to all that, we aren't even the size of a quark on the butt of a bacterium...
> Estimates for the mass of material that falls on Earth each year range from 37,000-78,000 tons. Most of this mass would come from dust-sized particles.
I guess this means the Earth gets slightly bigger and gravity becomes slightly stronger over time, but it's a much smaller effect than, say, the ocean's tides creating drag that slows the rotation of the Earth.
Presumably, the materials we mine and bring back aren't going to have the same composition as micrometeorites, since space gravel exactly isn't economically valuable. As long as we aren't bringing back super toxic or environmentally damaging stuff that's rare on Earth, I'm not too worried. Also, I expect all but the most valuable elements (e.g. gold, platinum) will be re-used in space to build infrastructure.
It's interesting that a robust space launch economy could compensate for the thousands of tons of annual space gravel, and cause the Earth to maintain its mass at a constant value.
Worst case we can always recycle that space junk but it's still way cheaper to recycle what we have on our surface before we run out of mines or grab stuff from orbit.
Headquartered yes, but the barge ~~launches~~ landings keep making me think long term SPaceX will be looking at extra-territorial options.
I'm sure every country they serve will attempt to regulate it, just like every country currently tries to regulate the internet. With mixed success.
Note, however, that all states are capable of regulating receivers. Many smaller dictatorial states ban (generally in vain) pointing your dish at certain satellites. The big ones, democratic and otherwise, usually just condition the permission to operate as a business in their country (salespeople, support, etc.) on satisfying regulatory concerns.
Putting 4425 in MEO, another ~7500 in LEO, and maybe a few in higher orbits, is likely a plan to reduce latency and increase bandwidth.
SpaceX has already launched some (50?) IridiumNEXT satellites, a planned constellation of 66 operational in LEO, plus 9 spares in a lower orbit, and 6 spares on the ground.
All these other companies follow the guidelines.
There was a rash of these schemes in the 1990s. Teledesic was the most similar one, and they went bankrupt and the constellation never launched. Voice-centric Iridium and Globalstar did launch, though, but they also went bankrupt but continued operating and have been refreshing their constellations. Iridium does sat-to-sat and is thus more capable, but Globalstar does not (they do "bent pipe" ala OneWeb).
And there's also Telestar's LEO constellation also being launched nowadays. It's sat-to-sat and is closer to Teledesic in size than SpaceX's Starlink.
These 1500 satellites are probably, on average, the size of a van. Is 1500 vans distributed on surface of the earth "much"? These SpaceX / Starlink satellites are considerably smaller - about the size of an oven or washing machine. What does it mean for 4500 ovens spread out over the surface of the earth to be "much"?
Any pointers? :)
>NASA and the DoD cooperate and share responsibilities for characterizing the satellite (including orbital debris) environment. DoD’s Space Surveillance Network tracks discrete objects as small as 2 inches (5 centimeters) in diameter in low Earth orbit and about 1 yard (1 meter) in geosynchronous orbit. Currently, about 15,000 officially cataloged objects are still in orbit. The total number of tracked objects exceeds 21,000. Using special ground-based sensors and inspections of returned satellite surfaces, NASA statistically determines the extent of the population for objects less than 4 inches (10 centimeters) in diameter.
GGP was trying to make the point that airplanes don't collide and that they travel fast but that's not the whole story, there are a lot of people working hard to keep it that way.
Also, even though NASA is tracking stuff there isn't much they can do about it, it's mostly to help determine new orbits and to make sure that launches do not accidentally intersect with some chunk of space debris.
We can use tracking and modern software solutions to plan where to put new satellites.
4500 is far from the maximum possible.
And of course they will do just that.
But satellites carry only relatively little propellant and the bulk of it is used to maintain altitude, especially for LEO/MEO satellites. Serious course changes are going to be pretty rare whereas they are the norm for anything with wings.
On another note, airtravel (not general aviation) tends to happen in 'corridors' with traffic control handing over at the borders of control zones. For satellites the situation is vastly different.
The same technological solutions that we've found for aerospace have almost no application in satellite orbital computations and the management of fleets of satellites.
Take a look at the airspace around a major airport when a storm system moves in. Airspace is absolutely congested.
The dimensions that appear in the FCC application are 4.0 x 1.8 x 1.2 meters. About size of a small passenger van actually. Doubtless that will not be the launch size, but they will have these dimensions while in operation.
SpaceX proposes to deorbiting the satellites much faster then international regulations require.
Low orbit satellites will fall back to earth much sooner than ones in higher orbit. I would also expect SpaceX to responsibly de-orbit and scuttle their satellites, if for no other reason than to make their own lives easier.
Probably not; all such endeavours are met by fear. Allow me to further unnerve you; this is just the first phase. The complete system, should it ever be realized, will have more than 8,000 satellites. And that's just SpaceX. There are competitors planning to launch systems of similar scale.
My wife called it the 'Cambrian explosion of space.' Effective, if not entirely correct, analogy.
If you arbitrarily regulate everything before you even begin to innovate, you'll never know what inventions could have been created: that's why there hasn't been hardly any innovation in housing construction over the last 20 years.
Or it would require qualifing all materials before being uses. That would increase time before deployment massivly, making new devlopment less attractive. Economist talk about 'permissionless innovation' being incredible important for progress.
And if you think 4.5k is a lot wait until you hear about phase 2. Thankfully that is in close LEO and without constant propulsion things would deorbit in a matter of weeks. See https://www.cnbc.com/2018/02/17/spacex-testing-its-own-satel...
Also it's not like even this particular orbit will be full when SpaceX is done at 1150 km orbit the 4425 satellites would each have a bit over 80,000 km^2 to themselves on average if they're spread out evenly.
Operational satellites are not considered space-junk since they typically have predictable or fixed orbits which can be avoided. Space junk is non-operational stuff, with potentially unpredictable orbits.
NORAD tracks the location of everything big enough to track, and makes it all available.
Well not 'all'; naturally the published elements omit objects related to 'national security' and objects which weren't announced as space vehicles e.g. debris.
They are also published under a very restrictive license; I can't forward the elements to you, nor publish anything derived from them, such as predictions for a pass. End-user eyes only.
It's like the people who bash NASA for having failures. This has never been done before!
It's pushing the hype with often little basis, which is guaranteed to create dislike from people disagreeing. It's very different from bashing mistakes IMHO.
You see, the the projected promise is not to have electric cars in production. It is to build cars with tech that is far advanced and game changing, to a point that owning an ICE vehicle does not make sense...
> but also land rockets those are definitely not vaporware
The promise is not that they will build rockets. The promise is mars. That is why people are cheering for them and is investing in them..
Then there is Hyperloop. Classic vaporware..You might be seeing why I think these are vaporware now...
Thanks idiots of HN for flagging the comment. A fool and his money is soon parted. If there are too many fools in the world, it is only the preservation of that law that is dictating that entities like Musk should appear.
Also, not only has SpaceX demonstrated reuse, but they've done so ~10 times with Falcon 9 in just over a year.