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Comment by headcanon | Hacker News Reader

I'm sure they have their reasons, but it seems a bit odd to do it there instead of in Brownsville TX, where they already have facilities, and its on the same side of the continent as Florida, meaning they don't have to ship them across the Panama Canal.

Its possible that their rocket-building expertise resides in LA and they want to keep it close to home, and shipping the rockets isn't as much a concern.

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As I understand it basically all of their existing engineering staff works at their Hawthorn, CA complex, so this is the closest location to that which will allow them to ship by water.

So far their prototype giant carbon fiber tanks have been manufactured at a partner's facility in Washington state so this should allow them to receive those shipments pretty easily.

https://www.goskagit.com/news/local_news/spacex-fuel-tank-le...

For now yes, but it looks like SpaceX are considering doing at least some manufacturing in Texas in the long run.

https://www.teslarati.com/spacex-mars-rocket-factory-south-t...

Yep, I think it makes sense to do initial development close to their main engineering workforce, but later final assembly and refurbishment could happen closer to the launch sites.

Wow, so strange to see my hometown's newspaper on HN.

Based on the info in the r/spacex thread where all of this was first posted, it seems like this facility is mostly for developing the prototypes of the BFR/BFS before the vehicle goes into full production.

My guess is that your second thought about their rocket building expertise being in LA caused them to choose LA for the prototyping and that a BFR/BFS factory at Boca Chica or Cape Canaveral is still a distinct possibility.

Shipping is less of a concern for a fully reusable system. Instead of shipping a giant rocket for every launch, you ship it once and use it for dozens or hundreds of launches.

Launch it from LA and land it in Florida for the test flight?

If the rocket can be used without limit this almost makes perfect sense.

If you launch to the west this might be viable. The government wouldn't be particular thrilled about test flights over land (or any flight over land), but for a test flight you would want something longer than a jump across the continent anyway.

Rockets rarely launch at a retrograde (western) orbit because you have to overcome the earth’s rotation to reach orbital velocity, rather than the speed boost you get from launching with the earth’s rotation. IIRC, satellites launching from Vandenberg AFB in California take a polar orbit.

OTOH if they're just trying to get from California to Florida they don't need full orbital velocity.

Even if they went all the way up to the ISS's orbit (which would be useless both because it's a test flight and because they would be going the wrong direction), the difference between going in a western or eastern orbit is a ~10% difference in delta-v requirements. Normally that's an enormous difference, but if you can just decrease the size of the test payload at will it shouldn't matter much beyond spending a few thousand dollars more on fuel.

It's not the height that counts, it's the sideways speed. Getting to 250 miles above sea level is relatively easy. Getting to 5 miles a second it far harder.

But if you're not aiming for orbital velocity the earth's rotational speed doesn't make any difference -- the relative speed of start and end points are the same. It doesn't take more fuel to travel west than east because of the rotation of the earth (jet stream sure, but if rockets are affected by the jet stream there's something seriously wrong)

Disclaimer: my entire picture of orbital dynamics comes from KSP

Check your orbital velocity at the surface. It's not 0. The direction you head does matter.

I don't think anybody is allowed to launch rockets from the United States where any part of the boost phase is over land.

Traditionally, rockets dropped their boosters. If they are no longer dropping large explosive things, such a requirement could go away.

Even if the intent is not to drop boosters, as long as there's some reasonable chance boosters will be dropped (accidentally), I can see that requirement sticking around.

> If they are no longer dropping large explosive things

If you were a rocket engineer, would you stake your life on it? Every single launch?

Are you afraid of jumbo jet engines falling out of the sky near airports?

Exactly, that's the end goal.

The energy output of a jumbo jet is four orders of magnitude less then that of a rocket. A jet engine is equivalent to a controlled fire. A rocket is equivalent to a controlled nuclear explosion.

There's almost as much energy stored in a BFR as there is in the nuclear bomb dropped on Hiroshima. This energy is released over 3 minutes.

Considering their long term plan involves building pads out in the ocean and doing suborbital hops between cities:

https://www.youtube.com/watch?v=zqE-ultsWt0

maybe

You still need to inspect it after each launch and perhaps repair? I'd imagine there would be some overlap with manufacturing if only for the expertise.

Currently with the Falcon 9 they do the manufacturing in Hawthorne, initial testing in McGregor Texas, and then in Florida they have facilities for integration and inspection. They are leasing/building more facilities in Florida at Port Canaveral to handle inspection and refurbishment of landed boosters.

Eventually it might make sense to move final assembly closer to the launch site for BFR, but I would expect a lot of the component assembly (like engines) to remain in Hawthorne.

At first, but I believe the plan would be multiple flights per day with regular maintenance/inspection/rebuild intervals similar to how aircraft are maintained.

From [1]

>In addition, the lease would accommodate recovery operations undertaken by Space Exploration Technologies to bring to shore vehicles returning from space that are retrieved by an autonomous drone ship offshore.

So they would have the option of doing that at the new manufacturing facility (even though we can speculate that that would not be the norm).

1: https://www.reddit.com/r/spacex/comments/85i6rd/bfr_producti...

As far as I know, all SpaceX rockets so far have been made in their Hawthorne facilites and the new ones are just 20 minutes away. So they can either just move workers to the new facilities or at least keep the staff of both in close contact. Also Elon usually is either in Freemont or in Hawthorne, her certainly doesn't want to add more travel to his schedules.

I wouldn't exclude the possibility that the eventual plan is to do both -- or to manufacture the BFR (the rocket part) in one location, and the BFS (the spaceship part) in the other. The article does mention that the LA location is intended to be able to receive (and presumably service) recovered vehicles, which would make a lot of sense for droneship landing after a Vandenberg launch.

At any rate, I personally haven't heard any speculation about them moving BFS testing outside of Texas, but /r/spacex might very well be the most reliable way to find out (unless you're a SpaceX employee!)

Is the BFR also expected to land on droneships?

No, the plan is for it to always return to the launch site.

To add to this, SpaceX has said at some point that they are planning to land the BFR directly back on the launch clamps to remove the need for landing legs.

Sounds like a nice option and a scary default.

When Elon (I think it was him) was talking about it, he seemed pretty confident that they could do it effectively.

They already land the Falcon 9s on a relatively small area; with a bit of extra maneuvering capability right before touchdown, along with the Raptor engine's deep throttling ability, it should be entirely possible to do pinpoint landings.

I would take it to mean they anticipate more launches from Vandenberg.

Which has constraints on both see and land routes into it.

There are (afaik) no options to unload sea freight at vafb. And the roads to vafb are not great.

There is a harbour at VAFB. It’s the only way Delta IV boosters can get there. Was originally build for the shuttle, I believe.

Whether it’s big enough for BFR, I’m less certain...

Edit: https://spaceflightnow.com/2014/11/09/delta-mariner-drops-an...

Well I stand corrected! Thank you!

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