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The Space Shuttle's main engines burn LO2/LH2 (liquid oxygen & liquid hydrogen) and produce 400,000 lbf (1.8 million Newtons) of thrust. The resulting exhaust is heat and water vapor.
Space Shuttle main engine - Wikipedia, the free encyclopedia
My main concern really is that by lowering the cost of launches to LEO, Spacex will increase this traffic by approximately an order of magnitude (10x), and since they are using fossil fuel technology this will increase the CO2 emissions from the space industry by a similar factor (or more). All this at a time when we need to be decreasing CO2 emissions, not increasing them.
Tdave
Member
Well stated, Chris.
So do we have an idea of the magnitude of the increased emissions? As a percentage of current transportation emissions, for example? Or maybe as number of EVs it would take as an offset?
So do we have an idea of the magnitude of the increased emissions? As a percentage of current transportation emissions, for example? Or maybe as number of EVs it would take as an offset?
I think that at this point any number given for the increased magnitude of emissions would be a guesstimate, since we don't know just how much LEO launches will increase. Generally speaking though, as the price of a service drops, more people/entities can afford it, and it is utilized more.
Space industry emissions of CO2 as a percentage of overall transportation emissions has got to be very small, because there are relatively few launches per year compared to airplane flights, ships, trains, cars, etc. The question is, should space industry emissions be increasing while every other area of human activity is being asked to reduce emissions?
I don't have any hard numbers for this, but I'm going to speculate that the amount of CO2 emissions produced to date by SpaceX (launches plus engine testing), plus those produced by their first few Falcon 9 launches, will exceed the total amount of CO2 emissions saved by all the hybrid and electric vehicles in the US in the last ten years. Again, this is just speculation, but I believe that it's close to the truth.
As has been discussed here at lenght, the production and storage of H2 is certainly no zero carbon operation. Nor is the production of another set of space shuttles since this fleet has reached, perhaps exceeded, it's life span. So I'm not certain your example still doesn't have tradeoffs that have to be considered. I have no idea what the comparison is, do you Chris?
Production of H2 can be zero emissions. It's true that most H2 produced today uses methane (CH4) as a raw material, and as a result also produces CO2, but it doesn't have to be this way. Hydrolysis of water using energy from low CO2 emissions sources can provide liquid H2 with a very low carbon footprint.
2H2O + E --> 2H2 + O2
I wasn't suggesting building more space shuttles. I was pointing out that there are ways to get to LEO without burning huge volumes of fossil fuels.
johnr
Member
Rocket fuel emissions don't strike me as a big deal...at least not yet. The market just isn't large enough at this point.
But this...well, the title speaks for itself:
Big polluters: one massive container ship equals 50 million cars
But this...well, the title speaks for itself:
Big polluters: one massive container ship equals 50 million cars
This is a topic that has been coming up a lot recently for obvious reasons, but there are a lot of factors that should be taken into account that are not often discussed.
For comparison:
A fully loaded Falcon 9 weighs about 330 tons. Roughly 90% of that is propellant and around 50% of that is fuel - i.e. ~150 tons.
A Boeing 747-400 also holds 150 tons of fuel for a 14 hour flight, so to first order the emissions are about the same (I say first order because burning the fuel in air vs. oxygen will produce different by products).
There are around 1000 trans-Atlantic flights every day alone - compare this with a rocket launch average of about 5 per month. The number of flights around the world daily (all durations and types of plane) is around 90000.
Not all rockets are equal. The shuttle boosters produce clouds of hydrochloric acid (as do many other solid boosters like the Ariane 5's) and the Russian Proton, another popular satellite launcher, uses highly toxic fuels that occasionally are released unburnt when stages crash back to Earth. Clearly CO2 is not the only consideration and it could be argued that RP-1 is a cleaner fuel than these other rockets use.
As far as I know, the only true "ZEV" rocket is the Boeing Delta 4, as it only uses LH2/LOX engines (even the boosters use this combination), but it is very expensive.
Another consideration is what the payloads launched on the rocket are to be used for. For example, once a comms or broadcast satellite is in orbit it generally runs for 15 years on solar power. It could be providing TV, radio, broadband or cell phone coverage that otherwise would require a nationwide network of terrestrial transmitters or cable systems which will consume many, many megawatts of power 24/7. In this scenario, the emissions from that single launch have to be balanced against those of 15 years of operation.
In a nutshell, if SpaceX does manage to increase the launch rate by an order of magnitude (and this is simplistic, as there a factors such as spacecraft cost, logistical and regulatory issues that need to be considered), it will still be a drop in the ocean compared to aircraft emissions.
I'd be more concerned about satellite industry personnel having to make regular trips to their international suppliers, which unfortunately has to happen many, many times during the life of a typical programme.
For comparison:
A fully loaded Falcon 9 weighs about 330 tons. Roughly 90% of that is propellant and around 50% of that is fuel - i.e. ~150 tons.
A Boeing 747-400 also holds 150 tons of fuel for a 14 hour flight, so to first order the emissions are about the same (I say first order because burning the fuel in air vs. oxygen will produce different by products).
There are around 1000 trans-Atlantic flights every day alone - compare this with a rocket launch average of about 5 per month. The number of flights around the world daily (all durations and types of plane) is around 90000.
Not all rockets are equal. The shuttle boosters produce clouds of hydrochloric acid (as do many other solid boosters like the Ariane 5's) and the Russian Proton, another popular satellite launcher, uses highly toxic fuels that occasionally are released unburnt when stages crash back to Earth. Clearly CO2 is not the only consideration and it could be argued that RP-1 is a cleaner fuel than these other rockets use.
As far as I know, the only true "ZEV" rocket is the Boeing Delta 4, as it only uses LH2/LOX engines (even the boosters use this combination), but it is very expensive.
Another consideration is what the payloads launched on the rocket are to be used for. For example, once a comms or broadcast satellite is in orbit it generally runs for 15 years on solar power. It could be providing TV, radio, broadband or cell phone coverage that otherwise would require a nationwide network of terrestrial transmitters or cable systems which will consume many, many megawatts of power 24/7. In this scenario, the emissions from that single launch have to be balanced against those of 15 years of operation.
In a nutshell, if SpaceX does manage to increase the launch rate by an order of magnitude (and this is simplistic, as there a factors such as spacecraft cost, logistical and regulatory issues that need to be considered), it will still be a drop in the ocean compared to aircraft emissions.
I'd be more concerned about satellite industry personnel having to make regular trips to their international suppliers, which unfortunately has to happen many, many times during the life of a typical programme.
John,Rocket fuel emissions don't strike me as a big deal...at least not yet. The market just isn't large enough at this point.
But this...well, the title speaks for itself:
Big polluters: one massive container ship equals 50 million cars
thanks for the link. That is one disturbing article. It makes a good case for nuclear powered ships. It's something that really needs to be regulated.
Tdave
Member
Rocket fuel emissions don't strike me as a big deal...at least not yet. The market just isn't large enough at this point.
But this...well, the title speaks for itself:
Big polluters: one massive container ship equals 50 million cars
That article only talks about SOx pollution. What about the greenhouse gas emissions?
John and David,
I agree that the launch services industry produces a very small percentage of the overall CO2 emissions from transportation globally. I already acknowledged that in post # 85 (2nd paragraph) on this thread. What concerns me is that the launch services industry (in particular, SpaceX) is going to be increasing their emissions of CO2 while every other area of human endeavor is being asked to decrease emissions. This is especially irksome knowing that there are other lower carbon technologies that could be employed to achieve the same results. LO2/LH2 may be a bit more expensive, but there are many benefits to it also:
From:
John F. Kennedy Space Center -* KSC Fact Sheets and Information Summaries
In addition, Elon has mentioned in the past that the fuel costs represent a relatively small percentage of the overall launch costs, so why not spend a little more and spring for the cleaner technology? They are already using cryogenic LOX afterall, and the Kennedy Space Center has facilities to handle LH2 because of the Shuttle.
Finally, when one industry or entity is allowed an exception to certain rules, then many others start lobbying the government to also become exceptions. The overall result is to render the original legislation ineffective in acheiving it's purpose. Although no legislation has been passed at this point to mandate industry or individuals to reduce CO2 emissions, I believe that it is just a matter of time.
Perhaps SpaceX already has plans to transition to cleaner, more efficient LH2 technology, I don't know, but it's certainly a direction that I'd like to see them move in.
I agree that the launch services industry produces a very small percentage of the overall CO2 emissions from transportation globally. I already acknowledged that in post # 85 (2nd paragraph) on this thread. What concerns me is that the launch services industry (in particular, SpaceX) is going to be increasing their emissions of CO2 while every other area of human endeavor is being asked to decrease emissions. This is especially irksome knowing that there are other lower carbon technologies that could be employed to achieve the same results. LO2/LH2 may be a bit more expensive, but there are many benefits to it also:
From:
John F. Kennedy Space Center -* KSC Fact Sheets and Information Summaries
In addition, Elon has mentioned in the past that the fuel costs represent a relatively small percentage of the overall launch costs, so why not spend a little more and spring for the cleaner technology? They are already using cryogenic LOX afterall, and the Kennedy Space Center has facilities to handle LH2 because of the Shuttle.
Finally, when one industry or entity is allowed an exception to certain rules, then many others start lobbying the government to also become exceptions. The overall result is to render the original legislation ineffective in acheiving it's purpose. Although no legislation has been passed at this point to mandate industry or individuals to reduce CO2 emissions, I believe that it is just a matter of time.
Perhaps SpaceX already has plans to transition to cleaner, more efficient LH2 technology, I don't know, but it's certainly a direction that I'd like to see them move in.
johnr
Member
Chris, you make some good points. If the fuel costs are negligible then they have little excuse not to go with the cleaner fuel. So the fact that they are not, leads me to assume that something more than cost of fuel is involved. Maybe LH2 is more difficult to harness safely as a rocket fuel. I'm not a rocket scientist so I have no idea. I guess it wouldn't hurt SpaceX to at least dedicate a bit of R&D in that direction.
I'm not saying never, but SpaceX specifically went the kerosene route due to ease of handling, which translates into much lower costs (in terms of logistics and the vehicle itself). If they tried to do LH2 from day one it would probably never have been viable. NASA may well have handling facilities, but that is one of the contributors to the Shuttle's billion dollar per launch costs.
Elon has apparently talked about developing a hydrogen upper stage but I can't see a source for that. It certainly would not help much in terms of emissions or consumption. Perhaps more promising is the use of biodiesel in rockets designed to run on kerosene - something that SpaceX could potentially switch to at some point.
Elon has apparently talked about developing a hydrogen upper stage but I can't see a source for that. It certainly would not help much in terms of emissions or consumption. Perhaps more promising is the use of biodiesel in rockets designed to run on kerosene - something that SpaceX could potentially switch to at some point.
I'm surprised that Elon would want to sell any ownership interest in SpaceX at this point. As far as I know, Elon owned 100% of the company up to this point, and he has said that the company is profitable. It would appear that most of their R&D costs have been covered, so why is he trying to raise more capital?
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