totm nov 2023 SpaceX Discussion Thread

[tater]

They need a starlink dish in the trunk.

[Beccab]

Chris playing the banjo > the version of Take On Me you know of

[mikegarrison]

1 hour ago, Beccab said:

- SpaceX estimating that they will do 10 tank tests a month with a failure rate of 10%. They must have an insane amount of confidence in their build techniques to have such a low rate of failure estimate.

Um .. what?! 10% failure rate is not something most manufacturing companies would associate with "an insane amount of confidence". That would be, in fact, shockingly bad.

I will give SpaceX the benefit of the doubt here and assume this is just a scoping thing along the lines of "even if we had a 10% rate of failure, the environmental impact would be ...".

[mikegarrison]

Another quote from this document:

Quote

Launch-related and power plant operations are estimated to emit 47,522 metric tons of carbon dioxide equivalent per year. This estimation is substantially less than the total GHG emissions generated by the United States in 2018.

W. T. F.

It's crazy to compare this one plant to the GHG emissions of the ENTIRE USA, and then argue that means it's not significant.

I don't know how usual or unusual it is to have a statement like this in the EA, but it's a frigging useless standard to meet -- comparing one operation to the entire US output of GHG. By this standard *anything* is going to be insignificant.

[tater]

That figure looks to be about 12,000 hours of flying a commercial jet. Looks to be in the ballpark of what an airline like United might fly in a day. (total ballpark, I'd be happy if it's in the same order of magnitude).

Amazon.com released 60.64 million tons of Carbon in 2020. So this SpaceX facility for a whole year is equal to <7 hours of Amazon impact as a reality check.

Another way of looking at it is that Boca Chica will release as much carbon as amazon does in 1 year after it has been operating for 465,754 days (1276 years).

Edited September 17, 2021 by tater

[tater]

31 minutes ago, mikegarrison said:

Another quote from this document:

W. T. F.

It's crazy to compare this one plant to the GHG emissions of the ENTIRE USA, and then argue that means it's not significant.

I don't know how usual or unusual it is to have a statement like this in the EA, but it's a frigging useless standard to meet -- comparing one operation to the entire US output of GHG. By this standard *anything* is going to be insignificant.

Yeah, that's bizarre. I could see a reporter writing something that clueless, but not themselves in the impact study—seems like they should compare to a similar industrial facility in the region, like a nearby refinery, the Brownsville airport, etc.

Edited September 17, 2021 by tater

[mikegarrison]

7 minutes ago, tater said:

Yeah, that's bizarre. I could see a reporter writing something that clueless, but not themselves in the impact study—seems like they should compare to a similar industrial facility in the region, like a nearby refinery, the Brownsville airport, etc.

And it they had, I would have been fine with it.

[tater]

3 minutes ago, mikegarrison said:

And it they had, I would have been fine with it.

Yeah, me too. It literally took me a few seconds to compare to planes and Amazon (since I assumed they'd have published data on carbon emissions), you'd think whoever drafts that stuff would have done something that is at least comparable.

The murders in Chicago this month are substantially lower than those in the entire US combined for a decade—nothing to see here, move along!

 

[wumpus]

35 minutes ago, mikegarrison said:

Um .. what?! 10% failure rate is not something most manufacturing companies would associate with "an insane amount of confidence". That would be, in fact, shockingly bad.

I will give SpaceX the benefit of the doubt here and assume this is just a scoping thing along the lines of "even if we had a 10% rate of failure, the environmental impact would be ...".

Do all these manufacturing companies have the mass margins of space?  Sure, Boeing  might take mass in their airplane business as the strictly space bit of aerospace, but it makes a lot of sense to push the process as far as it would go.  Elon might decide that if you don't blow up 10% of your tanks you could easily save a few kg.  Granted, part of this is thanks to using stainless steel as opposed to carbon.  Not sure if it would be worth it with carbon tanks.

I think sometime in the 1990s, silicon chip manufacture finally got yields (100-failure rate) from around 30-40% yields to somewhere north of 80%.  I wouldn't be surprised if modern yields have been creeping back down (they are some of the strictest secrets in the business).  You really want to compare apples to apples (although your experience with aircraft is probably closest).

35 minutes ago, mikegarrison said:

Another quote from this document:

W. T. F.

It's crazy to compare this one plant to the GHG emissions of the ENTIRE USA, and then argue that means it's not significant.

I don't know how usual or unusual it is to have a statement like this in the EA, but it's a frigging useless standard to meet -- comparing one operation to the entire US output of GHG. By this standard *anything* is going to be insignificant.

If they wrote that, then I'm guessing that the EPA regulations are designed to be impossible to not to pass (but will generate paperwork that will require the EPA to be continually funded, especially in the districts of powerful congresscritters).

According to the links below, that's the annual CO₂ output of ~3,000 Americans.  Since they employ ~10,000 Americans, it seems hard to claim that they are emitting "too much" (compared to all other US companies).

https://www.macrotrends.net/countries/USA/united-states/carbon-co2-emissions  confirmed here https://ourworldindata.org/co2/country/united-states  

 

 

[tater]

 

[cubinator]

56 minutes ago, tater said:

That figure looks to be about 12,000 hours of flying a commercial jet. Looks to be in the ballpark of what an airline like United might fly in a day. (total ballpark, I'd be happy if it's in the same order of magnitude).

Amazon.com released 60.64 million tons of Carbon in 2020. So this SpaceX facility for a whole year is equal to <7 hours of Amazon impact as a reality check.

Another way of looking at it is that Boca Chica will release as much carbon as amazon does in 1 year after it has been operating for 465,754 days (1276 years).

Thanks for the actually useful comparison. Indeed, the SpaceX launch site will generate less greenhouse gases than the US, and they will also launch less mass to orbit than that of the Earth.

[tater]

7 minutes ago, cubinator said:

Thanks for the actually useful comparison. Indeed, the SpaceX launch site will generate less greenhouse gases than the US, and they will also launch less mass to orbit than that of the Earth.

 

Quote

For a typical world-scale 300,000 barrel per day refinery, this will lead to CO2 emissions ranging from 0.8 up to 4.2 million tons of CO2 per year.

Unsure what the refineries in nearby Corpus Christi do, but that range is 17 to 88 times the impact of Starbase per facility.

Edited September 17, 2021 by tater

[mikegarrison]

4 hours ago, wumpus said:

Do all these manufacturing companies have the mass margins of space?  Sure, Boeing  might take mass in their airplane business as the strictly space bit of aerospace, but it makes a lot of sense to push the process as far as it would go.  Elon might decide that if you don't blow up 10% of your tanks you could easily save a few kg.  Granted, part of this is thanks to using stainless steel as opposed to carbon.  Not sure if it would be worth it with carbon tanks.

I can't understand anybody arguing this.

I can tell you that we pressure test every single airplane before we let it go up for a first flight. And if 10% failed, not only would heads be rolling, but we probably wouldn't be in business anymore.

There is just no way you can build something like this and only be 90% sure it can even hold pressure, but then argue that it is able to be launched, landed, refueled, and launched again.

===========

We don't really test them because we expect anything to "fail". Instead, we're looking for the leak rate, to make sure it doesn't leak faster than we expect. (A certain amount of leakage is not only expected but designed in.)

And as a side note to the side note, if you are onboard during a ground pressurization test you can't go flying immediately after. You have to be careful, because you can actually get "the bends" from that.

Edited September 18, 2021 by mikegarrison

[tater]

The 10% loss is not for every flight article tank, I assume they will be making test tanks to try and drop mass. They already have 3.6mm steel rolls on site, and there was talk of 3mm.  Or was the claim they would somehow lose 10% in production?

 

Live in 23 hours.

[mikegarrison]

17 minutes ago, tater said:

The 10% loss is not for every flight article tank, I assume they will be making test tanks to try and drop mass. They already have 3.6mm steel rolls on site, and there was talk of 3mm.  Or was the claim they would somehow lose 10% in production?

I don't know. I read through the part about the tank testing, and it said nothing about any 10% failure rate. But it was talking about pressure testing every flight article (which is entirely reasonable).

[magnemoe]

4 hours ago, zolotiyeruki said:

Two launch mounts (and sets of catching arms) makes me wonder about the idea of a SuperHeavyHeavy, with two side boosters and a core.  I wouldn't want to be near such a beast during launch, that's for sure!

Second tower is backup in case other get hit by an first stage or other throttles like issues with the catch mechanism or other sub systems. 
That backup is needed for stuff like moonship who require filling up tankers in orbit. 

[derega16]

5 hours ago, zolotiyeruki said:

Two launch mounts (and sets of catching arms) makes me wonder about the idea of a SuperHeavyHeavy, with two side boosters and a core.  I wouldn't want to be near such a beast during launch, that's for sure!

With such distance, it will awkwardly apart that made SRB-X looks like SRBs are doing a French kiss

[SOXBLOX]

5 hours ago, tater said:

Another way of looking at it is that Boca Chica will release as much carbon as amazon does in 1 year after it has been operating for 465,754 days (1276 years).

Meanwhile, Blue Origin is using an innovative greenhouse emissions reduction technique.

Spoiler

It's called "Don't launch rockets". 

 

[tater]

 

[londalosis]

I totally agree with you. 

[tater]

 

[Beccab]

5 hours ago, mikegarrison said:

I don't know. I read through the part about the tank testing, and it said nothing about any 10% failure rate. But it was talking about pressure testing every flight article (which is entirely reasonable).

No, it is from the summary. Very specifically this:
"SpaceX is proposing to conduct approximately 10 tank tests a month. SpaceX estimates a 10 percent rate of anomalies during tank testing."

i.e. 10% success rate for tests and improvements, not for normal flights. Stuff like 3mm tanks, 3.6 mm, single block nosecones etc, which I presume also includes testing to rupture

Edited September 18, 2021 by Beccab

[tater]

Pretty sure a "tank test" != launch vehicle/spacecraft test.

[Beccab]

13 minutes ago, tater said:

Pretty sure a "tank test" != launch vehicle/spacecraft test.

Quoting again the doc:
"Operations include tank tests, pre-flight operations, suborbital launches, and orbital launches. SpaceX is
still in the testing stages of the launch vehicle, including ongoing Starship prototype tests that have been
approved under a separate license. SpaceX also will need to conduct similar tests of Super Heavy
prototypes, which have not yet been approved under a separate license. In the early stages of the
Starship/Super Heavy program, SpaceX would conduct more tests (tank tests, static fire engine tests, and
suborbital launches) and fewer orbital launches annually. If SpaceX becomes more successful with tests,
the program would shift to more orbital launches and fewer tests."

And the section the previous extract came from:
"SpaceX is still determining the number of prototypes that it will build and test. SpaceX is proposing to
conduct approximately 10 tank tests a month. SpaceX estimates a 10 percent rate of anomalies during
tank testing. An anomaly would result in an explosion and the spread of debris. The distance for which
debris could spread is considered the blast danger area; SpaceX would determine this area prior to the
test. The blast danger area for tank tests would be within the hard checkpoint area (Figure 2-4). Given
the rates above, SpaceX estimates that one tank test each month may result in an anomaly and
potentially an explosion."

Edited September 18, 2021 by Beccab

[KSK]

If it's good enough for Scott Kelly, it's good enough for me. 

They're astronauts.