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posted by martyb on Tuesday October 29 2019, @02:40AM   Printer-friendly
from the AKA-BFS dept.

SpaceX President and COO Gwynne Shotwell has revealed that Starship can carry 400 Starlinks satellites into orbit, up from the 60 recently launched using a Falcon 9 rocket. The cost per launch may be negligible:

Beyond Shotwell's clear confidence that Starlink's satellite technology is far beyond OneWeb and years ahead of Amazon's Project Kuiper clone, she also touched on yet another strength: SpaceX's very own vertically-integrated launch systems. OneWeb plans to launch the vast majority of its Phase 1 constellation on Arianespace's commercial Soyuz rockets, with the launch contract alone expected to cost more than $1B for ~700 satellites.

SpaceX, on the other hand, owns, builds, and operates its own rocket factory and high-performance orbital launch vehicles and is the only company on Earth to have successfully fielded reusable rockets. In short, although Starlink's voracious need for launch capacity will undoubtedly require some major direct investments, a large portion of SpaceX's Starlink launch costs can be perceived as little more than the cost of propellant, work-hours, and recovery fleet operations. Boosters (and hopefully fairings) can be reused ad nauseum and so long as SpaceX sticks to its promise to put customer missions first, the practical opportunity cost of each Starlink launch should be close to zero.

[...] Shotwell revealed that a single Starship-Super Heavy launch should be able to place at least 400 Starlink satellites in orbit – a combined payload mass of ~120 metric tons (265,000 lb). Even if the cost of a Starship launch remained identical to Starlink v0.9's flight-proven Falcon 9, packing almost seven times as many Starlink satellites would singlehandedly cut the relative cost of launch per satellite by more than the 5X figure Musk noted.

In light of this new figure of 400 satellites per individual Starship launch, it's far easier to understand why SpaceX took the otherwise ludicrous step of reserving space for tens of thousands more Starlink satellites. Even if SpaceX arrives at a worst-case-scenario and is only able to launch Starship-Super Heavy once every 4-8 weeks for the first several years, that could translate to 2400-4800 Starlink satellites placed in orbit every year. Given that 120 tons to LEO is well within Starship's theoretical capabilities without orbital refueling, it's entirely possible that Starship could surpass Falcon 9's Starlink mass-to-orbit almost immediately after it completes its first orbital launch and recovery: a single Starship launch would be equivalent to almost 7 Falcon 9 missions.

The Starlink constellation can begin commercial operations with just 360-400 satellites, or 1,200 for global coverage. SpaceX has demonstrated a 610 Mbps connection to an in-flight U.S. military C-12 aircraft. SpaceX is planning to launch 60 additional Starlink satellites in November, marking the first reuse of a thrice-flown Falcon 9 booster.

Also at CNBC.

Previously: Third Time's the Charm! SpaceX Launch Good; Starlink Satellite Deployment Coming Up [Updated]
SpaceX Provides Update on Starship with Assembled Prototype as the Backdrop
SpaceX Requests Permission to Launch an Additional 30,000 Starlink Satellites, to a Total of 42,000+
Elon Musk Sends Tweet Via SpaceX's Starlink Satellite Broadband
SpaceX: Land Starship on Moon Before 2022, Then Do Cargo Runs for 2024 Human Landing

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  • (Score: 2) by PiMuNu on Tuesday October 29 2019, @01:58PM (5 children)

    by PiMuNu (3823) on Tuesday October 29 2019, @01:58PM (#913266)

    > and time of the cross.

    Naively, I expect small deviations in the orbital period between adjacent (in height) satellites mean that the orbits can cross. I know T^2 ~ R^3 where R is the length of the semi-major axis; but orbits are not circular.

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  • (Score: 2) by deimtee on Tuesday October 29 2019, @02:14PM (2 children)

    by deimtee (3272) on Tuesday October 29 2019, @02:14PM (#913269) Journal

    Given how many he's going to put up, it would probably be easiest and most effective to simply ignore the possibility of collisions. They will be a very low probability event and losing a couple of satellites every year or so would be cheaper having that many satellites using fuel to try to maintain current minimum separation standards.
    At the very least I assume his satellites will be allowed much closer to each other, which is why he's trying to get control of an entire altitude band.

    (Any that collide will de-orbit very quickly, as a collision will always lower the kinetic energy, and hence the orbit. Kessler syndrome is not a problem that low down.)

    If you cough while drinking cheap red wine it really cleans out your sinuses.
    • (Score: 4, Interesting) by PiMuNu on Tuesday October 29 2019, @02:28PM (1 child)

      by PiMuNu (3823) on Tuesday October 29 2019, @02:28PM (#913272)

      > Kessler syndrome is not a problem

      Ah, okay. I guess that was my concern. I can't find any good info on that beyond definition. Thanks.

      By the way this is cool: []

      • (Score: 2) by deimtee on Thursday October 31 2019, @01:08AM

        by deimtee (3272) on Thursday October 31 2019, @01:08AM (#913964) Journal

        That is cool, be even nicer if it had some selection options like show only min/max/range apogee/perigee/mass/eccentricity.

        It also sort of makes my point about collisions between Sspacex's satellites being unlikely.

        If you cough while drinking cheap red wine it really cleans out your sinuses.
  • (Score: 2) by Immerman on Tuesday October 29 2019, @02:29PM (1 child)

    by Immerman (3985) on Tuesday October 29 2019, @02:29PM (#913273)

    It depends what you mean by "cross"

    As seen from below - as long as two satellites are at different altitudes, they can obviously "cross" without problems. With noncircular orbits you could even have A cross above B at one point, and B cross above A at the opposite point.

    As soon as you have two satellites passing through the exact same point in space though, things become a lot more complicated. So long as they have *exactly* the same period, you can do it - you just have to make sure they pass through the intersection point at different times. But if one satellite has a period even a few seconds longer than the other, then a collision becomes inevitable: If they missed each other by an hour this pass, then next pass they'll miss each other by 59 minutes and 55 seconds, then ...and 50 seconds. And after 720 passes passes they won't miss. And given the period of low orbits, that'll happen within a few months.

    Obviously you can correct one or both orbits before the moment of collision arrives, but that consumes limited propellant, increasing cost. And you have to do it regularly, because solar wind, atmospheric drag, interactions with Earth's magnetic field, etc. are all constantly nudging satellites out of their "assigned" orbits So generally you just want to avoid intersecting orbits altogether. Rings of satellites in the same orbit theoretically need the same adjustments to avoid collision - but they're subjected to much more consistent perturbations, and they remain at very low relative speed to each other, so you can rely on direct observations of positional stability rather than calculating future collisions based on imperfect velocity measurements.

    • (Score: 2) by deimtee on Wednesday October 30 2019, @08:26AM

      by deimtee (3272) on Wednesday October 30 2019, @08:26AM (#913629) Journal

      Speed in low earth orbit is typically several km/s. Your 5 second interval is a path >20 km long, of which the satellite is going to occupy a metres or so. Even if the heights match to the metre, the timing has to match up to less than a millisecond.
      I still maintain that the cheapest solution would be to simply assume they can pass through each other, and launch some spares for the very rare occasion that turns out to not be the case.

      If you cough while drinking cheap red wine it really cleans out your sinuses.