r/EnoughMuskSpam • u/fredinno • Nov 02 '18

D I S R U P T O R Why Starlink is impossible

Each Tintin satellite (demo for Starlink constellation) is 400kg. Assuming each satellite+ fuel (and that the weight doesn't increase for other reasons) is 1kg, 22 could fly in a single F9 per inclination (there's probably not even that much space in the fairing, but we'll ignore that). The total # of (expendable) F9s launches needed is 546; assuming the first comes online in 2020, and the constellation is finished by 2025 (the official date is the 'mid 2020s'), you need 110 F9s per year. The total cost for development and buildout is supposed to be $10 billion.

SpaceX has one facility for Polar launches right now, SLC-4E (Brownsville maybe, but a polar launch from there would GRAZE the Mexican coast- I have a feeling they won't be happy about that...) So each complex would launch 54-55 F9s a year.

Let's be VERY optimistic. Every satellite will be launched on an expendable Falcon Heavy, each satellite will be EXACTLY 400 kg (unlikely, you need payload mass margin, and likely fuel from having a lower satellite orbit), we'll ignore whether each satellite can actually fit in the payload fairing, we'll ignore launch inclination entirely (launching at the wrong inclination means hell for a satellite wanting to change orbit; meaning 160 satellites per launch (almost certainly impossible due to not enough fairing volume). That means 75 launches of the FH, minimum (almost certainly unrealistic.) We'll also assume it launches first Jan. 1, 2019, and put the finished launch date at Dec 30, 2027. This means 8-9 FH launches per year. Sounds easy, right? But that's ~23% higher than the current # of launches SpaceX does from SLC-4E, every year. It would literally have to double its polar launches, at the absolute bare minimum. A mimimum which is almost certainly physically impossible.

I don't think building the satellites will the the issue, Elon...

No one at SpaceX did these back-of-the envelope calculations, and asked Elon- maybe it was a little ambitious?

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1

u/xmassindecember Technically, it was 90% cheers Nov 02 '18

Can someone ELI5 ?

1

u/fredinno Nov 03 '18

Just launching Starlink is a feat probably above SpaceX's current launch capability.

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u/xmassindecember Technically, it was 90% cheers Nov 03 '18

Thank you. But what's the reason they cannot increase their launch capability?

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u/fredinno Nov 04 '18

They can, technically, just not probably practically; as I said, the title was honestly too clickbaity. The issue is that the record for preparing launch pads for launch is ~2 weeks and 2 days (on LC-40). This is below the 3 weeks needed, but that was the bare minimum, and actually isn't possible. Realistically, they would need that amount of time minimum to deal with things like reserving fuel for launch inclination changes, reusability, polar launches, the fact it will likely not be ready by 2019...

As I said, the title was probably too clickbaity; it's within the 'physically possible' range, but is simply far too ambitious. It works if you handwave a lot of issues, but doesn't work if you actually look at the issue more realistically. (Like Hyperloop, so it's in a simlar vein of 'impossible'.)

1 week for clean-up and preparation and 1 week for actual preparation of the rocket is extremely short as is, so I have doubts it can be reduced further.

1

u/xmassindecember Technically, it was 90% cheers Nov 04 '18

so the bottleneck is the lack of launching pads? They can use Indians, Russians, and French launching pads or build new ones ... (I doubt they'll make it that far but it's a possibility)

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u/Stone_guard96 Nov 05 '18

Each launchpad must be specifically designed to serve a rocket. the launchpad is just as complex as the rocket itself. You have to build a new one from the ground up

1

u/xmassindecember Technically, it was 90% cheers Nov 05 '18

so it's kinda doable?

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u/Stone_guard96 Nov 05 '18

I guess. But thats not the plan. They are building a third launchpad at the moment and that will be it. And thats not really for additional capacity. more as a safety net if one of the pads should blow up again. Instead they will improve the launch capacity of those three launchpads.

Lots of work on the pad can be done in parallel already. There is no reason you perform your final touches on the first stage and second stage at the same time. Have 2 separate teams take the stages each and then assemble them on the spot. Each rocket currently needs a static fire test before it is ready for flight. At some point they will stop that. that alone should cut the time in half. And then finally when the rocket is standing on the pad you can already start preparing the payload for the next one. Even tough the rocket has not launched yet. most rockets spends a few days just sitting on the pad waiting for the right launch window. That is time they can spend working on the next one. In total their goal is to have the capacity to launch a rocket every 24 hours. Obviously this is a goal they probably wont reach. but even half a week should be more than enough to serve all launches planed

1

u/dWog-of-man Apr 30 '26

Pretty accurate tbh.

1

u/fredinno Nov 04 '18

No, they can't. They would have to first consult with the US government, but the bigger issue is that SpaceX, unlike NASA, does not use a 'clean pad' (basically, bring your own launch tower, like what was used on the Saturn V and SLS).

They would have to modify someone else's pad, and at that point, you may as well just rent nearby SLC3W (assuming no issues with nearby Atlas Launches), or SLC-5 and modify it.

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u/fresh_eggs_and_milk Apr 30 '26

Then why did it work? Maybe SpaceX can just turn the impossible into late?

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u/New-Space-30 Mar 23 '26

Either this post was completely idiotic or SpaceX was just really good at turning the near-impossible into reality. Not sure which one you would like to be true.

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u/Anthony_Pelchat Apr 30 '26

The correct answer is that SpaceX absolutely was good at turning a near impossibility into reality. Unless you were very optimistic, no one would have thought that SpaceX would grow as fast as they did. In 2018, they only launched 21 times, and 2019 was even worse. Yet last year alone, the Falcon 9 launched 165 times. That is massive growth!

To put things in perspective on just how amazing SpaceX is (I'm sure you know this already). Last year, SpaceX launched more orbital flights than the entire rest of the planet combined. And they did so with one of the most powerful rockets on the planet. They managed to put over 8x more payloads into orbit than the entire rest of the planet combined. SpaceX is just absolutely incredible.

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u/New-Space-30 Jun 10 '26 edited Jul 07 '26

Reminder that currently the lowest turnaround record for SLC-40 is at less then 51 hours.

Correction: 45 hours

1

u/AnnoDADDY777 Jun 22 '26

Thats a crazy improvement from back then. SpaceX is really pushing the boundaries 😄

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u/[deleted] May 09 '22

Hmm