Apparently, the mass of a Gen2 Starlink satellite will be around 1 metric ton. It will also be too large to fit into a Falcon 9 fairing.

Given that it's basically still a "flying router", plus laser, and that the solar panels don't count against the launch size: What makes it so large and heavy?

  • 1
    $\begingroup$ I don't have enough details to put a whole answer together, but one of the things they want to do is apparently talk directly to cell phones, and I think that requires a higher-gain antenna than V1 (which had pizza-box sized sized phased arrays to talk to) $\endgroup$
    – Erin Anne
    Commented Aug 27, 2022 at 2:43
  • 1
    $\begingroup$ @ErinAnne Well, foldable structures are all the hype now ;-). But perhaps the antenna must be a rigid phased array, that would explain the size, perhaps. $\endgroup$ Commented Aug 27, 2022 at 8:47
  • 1
    $\begingroup$ Elon Musk has stated that the Gen2 satellites are "almost an order of magnitude" more capable. Yet, they are only ~4 times heavier. So, the question could just as well be: "Why will Starlink Gen2 be so small and light compared to its capabilities". $\endgroup$ Commented Aug 27, 2022 at 12:57
  • 3
    $\begingroup$ @JörgWMittag My new laptop is about 1000 times as capable as the one I had 25 years ago, yet weighs about half. "Capable" is too unspecific. These are not machines that move any matter: Sure, an excavator more capable is likely larger and heavier. "More capable" satellites surely use more energy, hence have larger solar panels, but those should not weigh that much and fold away nicely. So it's electronics or phased array. Neither should be so heavy though, I think. As said, the antenna(e) may need to be large. But heavy? perhaps batteries to bridge a few minutes in Earth's shadow? $\endgroup$ Commented Aug 27, 2022 at 13:59
  • 1
    $\begingroup$ runwaygirlnetwork.com/2014/10/… There is some historical precedence here with Connextion by Boeing. It was an internet to aircraft system. That was a case of phased array antennas that were too small. Those pointed up and couldn’t form a tight beam, causing signal bleed to other satellites. Starlink, of course, points down, but Elon’s comments about better, larger phased array antennas sounds an awful lot like the Boeing situation in reverse. Poor beam formation from an undersized antenna causing problems. Speculation, but something to watch $\endgroup$ Commented Sep 4, 2022 at 22:26

1 Answer 1


"Just a Flying Router"

This is... not the half pound plastic wifi router in your house.

I don't think there are firm numbers out yet, but the speculation I've seen is that bandwidth on a Gen2 is ~150-200 Gbps. A Cisco ASR 1000 series, terrestrial router with that kind of bandwidth weighs in at 184lbs.

That assumes fans for cooling. If they have to do a liquid cooling system with a radiator to reject heat to space - well that's more weight.

If they harden it for spaceflight, that's more weight.

So the router is already using up about 10% of the stated weight, and it's not even powered yet.

The high end ASR 1000 draws 4000 Watts, so that's about 260 square feet of rooftop solar panels (presumably aerospace panels are more efficient, but I don't have those numbers handy.)

Our mental image of the internet is some ephemeral cloud, but it turns out that it's made of cold, hard (heavy) infrastructure.

  • 1
    $\begingroup$ It's a good bet that Starlink's solar panels are closer to rooftop panels than to aerospace panels. A large part of how SpaceX has been getting costs down is by prioritizing price over weight -- they've got a cheap launch vehicle, so using it many times to launch cheap, heavy satellites is the low-cost option. $\endgroup$
    – Mark
    Commented Aug 31, 2022 at 20:25
  • 1
    $\begingroup$ @Mark It's not that much about the panels themselves, but without the pesky atmosphere in the way, there's much more light to be had in LEO than on the ground (roughly 1.5-2x as much). $\endgroup$
    – TooTea
    Commented Sep 1, 2022 at 8:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.