totm nov 2023 SpaceX Discussion Thread

[Wjolcz]

I think it would be best if they either pumped it back to the storage tank (it's not cryogenic like hydrogen, so it shouldn't be that hard, right?), or at least burn it instead of just venting.

Btw, I'm pretty sure they will probably do one of the two, or both, regularly once the rocket is more mature.

[CatastrophicFailure]

1 minute ago, Wjolcz said:

I think it would be best if they either pumped it back to the storage tank (it's not cryogenic like hydrogen, so it shouldn't be that hard, right?), or at least burn it instead of just venting.

Btw, I'm pretty sure they will probably do one of the two, or both, regularly once the rocket is more mature.

Generally, they do. That’s what the flare stack is for. That big release we saw yesterday wasn’t a norminal release, it was an aborted engine ignition. So, an “oops.”

[mikegarrison]

6 minutes ago, tater said:

What is the impact of other rocket propellants? Kerlox?

Mainly CO2. Rockets are known to contribute to black carbon (soot) emissions in the upper atmosphere, though, which has a number of concerns. Also water, which is otherwise somewhat rare in the upper atmosphere.

Solids are pretty notorious for their emissions. Most of them contain aluminum which ends up at particles in upper atmosphere. Also some other more exotic chemicals. All ozone depletion concerns.

And of course there are all the impacts from factories, workers, etc.

Edited August 27, 2019 by mikegarrison

[Wjolcz]

4 minutes ago, tater said:

What is the impact of other rocket propellants? Kerlox?

I'd imagine it's not that great either. Especially since it's not renewable (unlike methane). They probably won't do that but it would be pretty nice/cool if at least a part of the propellant was produced from water and air using some sort of sea-based solar power plant.

[tater]

1 minute ago, mikegarrison said:

Mainly CO2. Rockets are known to contribute to black carbon (soot) emissions in the upper atmosphere, though, which has a number of concerns. Also water, which is otherwise somewhat rare in the upper atmosphere.

Solids are pretty notorious for their emissions. Most of them contain aluminum which ends up at particles in upper atmosphere. Also some other more exotic chemicals. All ozone depletion concerns.

And of course there are all the impacts from factories, workers, etc.

Methane combustion products are CO₂, and water as well. On kerlox, there is presumably some leaking in distillation (I assume)... seems like the numbers are so tiny as a function of natural variation that it doesn't matter, honestly (if the wetlands contribution really varies by a factor of 2, large as it is relative to the worst-case for methane rockets).

[mikegarrison]

1 minute ago, Wjolcz said:

it's not renewable (unlike methane)

Most available methane is not "renewable" or from bio sources. The main source is from fracking. That's why it has become so cheap recently.

Methane captured from landfills or animal processing is usually used on site in co-generation plants.

1 minute ago, tater said:

tiny as a function of natural variation that it doesn't matter, honestly (if the wetlands contribution really varies by a factor of 2, large as it is relative to the worst-case for methane rockets).

Since it keeps being mentioned, wetlands have a lot of positive impacts (including carbon capture and sequestration). Rockets, not so much.

I work in an industry that a lot of people point to and blame for CO2 emissions -- but we're very active about trying to reduce it and/or mitigate it. I just see most rocket companies dodging the issue.

[Wjolcz]

18 minutes ago, CatastrophicFailure said:

That’s what the flare stack is for.

I haven't seen the yesterday's stream yet so don't know if they used it or not. I remember when one of the hops was aborted in July and I know they have it.

Assumed you guys were talking about the whole methane business because they didn't use it this time.

Edited August 27, 2019 by Wjolcz

[tater]

13 minutes ago, mikegarrison said:

I work in an industry that a lot of people point to and blame for CO2 emissions -- but we're very active about trying to reduce it and/or mitigate it. I just see most rocket companies dodging the issue.

Again, it's a matter of impact. Commercial air traffic is what, 100,000 flights a day, every day?

Still seems vanishingly small compared to even just natural variation (much less other human emissions of methane).

I know there's propane out in the world every time they fill my tank (no gas lines up the hill, here, we have tanks), I can smell it.

[tater]

On topic... I wonder if they can cut that central beam at the Cocoa, FL facility, and move the SS tank inside before the tropical storm hits...

[mikegarrison]

28 minutes ago, tater said:

Again, it's a matter of impact. Commercial air traffic is what, 100,000 flights a day, every day?

Still seems vanishingly small compared to even just natural variation (much less other human emissions of methane).

I know there's propane out in the world every time they fill my tank (no gas lines up the hill, here, we have tanks), I can smell it.

I'm tired of saying the same thing, and the forum is probably tired of hearing it.

But everything is additive. Just because there are other sources does not mean this source has no effect. Yes, we should prioritize larger and easier-to-fix sources first, but that doesn't mean other sources just get a free pass.

Road transport produces roughly 7x as much CO2 as aviation in the US, but that doesn't mean aviation isn't working on reducing their impact. (Personal note, I worked for years crafting the ICAO CO2 certification standard for international aviation -- an effort that was strongly supported by the industry itself.)

This is an opportunity for space companies to set themselves apart from the crowd and take leadership in their industry.

 

(ps. I see this whole discussion as being "on-topic". I mean, we're literally discussing SpaceX.)

Edited August 27, 2019 by mikegarrison

[Rakaydos]

20 minutes ago, mikegarrison said:

I'm tired of saying the same thing, and the forum is probably tired of hearing it.

But everything is additive. Just because there are other sources does not mean this source has no effect. Yes, we should prioritize larger and easier-to-fix sources first, but that doesn't mean other sources just get a free pass.

Road transport produces roughly 7x as much CO2 as aviation in the US, but that doesn't mean aviation isn't working on reducing their impact. (Personal note, I worked for years crafting the ICAO CO2 certification standard for international aviation -- an effort that was strongly supported by the industry itself.)

This is an opportunity for space companies to set themselves apart from the crowd and take leadership in their industry.

 

(ps. I see this whole discussion as being "on-topic". I mean, we're literally discussing SpaceX.)

Rocketry is an industry that regularly throws around chemicals that make methane look like a fruit smoothie in comparison. That SpaceX is ONLY dumping methane into the air is already miles ahead of the Russian and chineese space programs, that crash hypergolic-filled stages in populated territory. SpaceX has also talked about applying the Sabatier Reaction to earth-based fuel production, not just martian fuel production, making the rocket carbon neutral. (Once the reactor is ready for practical use)

So I don't know why you're whining.

[Terwin]

21 minutes ago, mikegarrison said:

I'm tired of saying the same thing, and the forum is probably tired of hearing it.

But everything is additive. Just because there are other sources does not mean this source has no effect. Yes, we should prioritize larger and easier-to-fix sources first, but that doesn't mean other sources just get a free pass.

SpaceX is not releasing large amounts of methane into the atmosphere on purpose, and they have that flarestack burning just in case some methane leak starts getting the local concentrations up high enough to be dangerous.

Lots of methane in the air when they have large tanks of volatile materials on-hand(like LOX and methane tanks) would be just asking for the entire facility to go up in flames, so they seem to be pretty careful to avoid that.

Yesterday's failed engine start is probably a majority of the methane released into the atmosphere from that facility, counting all leaks, intentional releases, and 'bits in the pipe when disconnecting' since they first started building starhopper.  Clearly this was not planned, and they shut it off in what 0.8 seconds?

What additional steps would you like them to take to avoid methane release, and how sure are you that those steps are not already being taken?

[mikegarrison]

32 minutes ago, Rakaydos said:

SpaceX has also talked about applying the Sabatier Reaction to earth-based fuel production, not just martian fuel production, making the rocket carbon neutral.

LOL. What, they are going to sift through one million tonnes of air to get 400 tonnes of CO2 that they can maybe make something like 100 tonnes of CH4 from? And they are going to use what energy source to do it with? Even if they capture it right from the stack so they don't have to mine it from the air, it takes a lot of energy to turn CO2 back into fuel. I mean, that's why we burn fuel in the first place -- to get that energy out of it.

That only makes the remotest amount of sense if we currently had more non-CO2-producing energy than we could use.

Biofuel-based production is probably better, but it has its own issues. LCA (life cycle analysis) is complicated, and sustainable, non-food biofuels are in high demand.

26 minutes ago, Terwin said:

SpaceX is not releasing large amounts of methane into the atmosphere on purpose

What additional steps would you like them to take to avoid methane release, and how sure are you that those steps are not already being taken?

I didn't say it was "on purpose".

I don't know what "additional" steps they are taking, because they don't seem to be talking much about what current steps they are taking. I've looked through their EISs and they aren't terribly forthcoming.

Edited August 27, 2019 by mikegarrison

[magnemoe]

1 hour ago, CatastrophicFailure said:

Generally, they do. That’s what the flare stack is for. That big release we saw yesterday wasn’t a norminal release, it was an aborted engine ignition. So, an “oops.”

This, its also an major fire hazard. This is why oil field flared gas long before co2 was an issue, early on they simply flared all the gas until they realized it was very cheap energy. Actually a bit weird how long that went on as its lots of energy intensive industries like aluminium who could use it but guess it require an gas turbine to be very effective. And to give methane some credit the shift from coal to gas has reduced US co2 emissions a lot. 

On modern oil rigs you don't even have an pilot flame who was needed to ignite the gas, one platform I worked on the design of they used an rocket to ignite the gas who kind of put this on the head. You fire something the size of an flare rocket up an pipe, at the end its an bend and the rocket is stuck there pointing it flame towards the gas until it burn out and drop down in an bucket as no more trust. Revolver magazine so you shoot another if the first did not work. 
Found that very cool yes you mostly have to flare during storms and the tower will get hit by lighting so you don't want anything who can fail up there so keep it extremely simple up there. 

And this, its an abort, worst issue would be damage to engine or other stuff around. 

 

[mikegarrison]

2 minutes ago, magnemoe said:

And to give methane some credit the shift from coal to gas has reduced US co2 emissions a lot.

Yes, this is very true.

[Terwin]

12 minutes ago, mikegarrison said:

I didn't say it was "on purpose".

I don't know what "additional" steps they are taking, because they don't seem to be talking much about what current steps they are taking.

Seeing as how the Texas department of public safety(DPS) is responsible both for monitoring the handling of hazardous materials, and is responsible for things like road closures, I think we can rest assured that they know when SpaceX is going to be handling a lot of methane(like a launch or engine test), and can easily monitor their activities in that regard, since they are already on-site to close the roads.

Thus far your argument seems to be 'SpaceX venting huge amounts of methane into the atmosphere is a bad thing!'

Can you offer any evidence that SpaceX is actually venting any methane?  How about more methane than when I light my stove at home(it can take a few seconds for the spark thing to light the gas stove)?

 

It *looks* like yesterday's 'oops' vented a fair amount for a second or two, but other than that, I am not aware of any evidence that SpaceX has ever vented unburned methane. 

Before you argue that they need to 'do more' could you at least provide some evidence that they are not already doing everything you could ask for?  

[mikegarrison]

Just now, Terwin said:

It *looks* like yesterday's 'oops' vented a fair amount for a second or two, but other than that, I am not aware of any evidence that SpaceX has ever vented unburned methane. 

Before you argue that they need to 'do more' could you at least provide some evidence that they are not already doing everything you could ask for?  

Again, we're going in circles. I don't know what steps they are taking, because they don't seem to be talking about it. Or estimating what their leakage is.

And yes, obviously it was the failed ignition event yesterday that made me raise the question.

Anyway, I'll continue this discussion if people have new things to say or ask about. Otherwise, I think we've all said the same things enough.

[tater]

We have no idea how much methane leaks (in their testing), though (as you have said---we also have no idea for Blue or ULA who will use LNG). The burn even the stuff they vent from the vehicle. (it's clearly visible when they detank after that abort before the short hop---looked like an explosion). The other venting we see is LOX.

So we know then burn off excess methane, how much do you imagine they are releasing unburned?

Note that for this hop the props mass is 30 tons (combined). The shorter hop and static fires have been lower still. Do you think they are leaking even 1% so far? Some fraction of 1%?

The population of Earth (humans) apparently releases about 73 tons of methane a day via their GI tract. That's ~62kg/day for the total employees of SpaceX. So since starting work on the Hopper, SpaceX employees have farted about 16 tons of methane. That's more than the entire tank for this 150m hop (assuming they didn't burn any of it at all). Wonder what the impact is of hiring in TX, where there might be more bean burritos than in FL...

Edited August 27, 2019 by tater

[tater]

 

[CatastrophicFailure]

34 minutes ago, tater said:

Hopper, SpaceX employees have farted about 16 tons of methane.

Shhhhhhhh.... 

Don't give Elon any ideas...

[tater]

So likely 5 local time in TX (about an hour from now).

[James Kerman]

 

[tater]

 

[Ultimate Steve]

About 3 minutes away, currently in planned 2 minute hold. Going for 5 PM CST.

Also, finally, a launch in my time zone!

[tater]

It'll be soon after deluge starts