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Same! I also think that spending money on a roundtrip to the moon is way better for humanity than spending it on champagne, caviar and cars.
by solidr53 10y ago
Same! I also think that spending money on a roundtrip to the moon is way better for humanity than spending it on champagne, caviar and cars.
- coryfklein 10y agoNot sure everyone will see it that way. One could look at it as taking the whole "wasteful private jet" to the extreme. Think of the sheer amount of fuel burned in the earth's atmosphere so a rich guy can fly in space. At least, I expect many will spin it that way.
- jfoutz 10y agoIsn't the exhaust just water?!?
- daeken 10y agoNot with the fuels used by the Falcon rockets. They use LOX + RP1 (kerosene), rather than LOX + LH (which does produce water).
- CommieBobDole 10y agoNot for the Falcon 9/Falcon Heavy that will be used in this launch; it uses RP-1 (basically very pure jet fuel, AKA kerosene) and liquid oxygen as fuel. The Shuttle and the new Space Launch System will use hydrogen/LOX, which exhausts basically water vapor.
- kobeya 10y agoWell, not the SRB part.
- deleted 10y ago[deleted]
- greglindahl 10y agoYeah, in both cases, the SRBs are the majority of the launch thrust.
- lutorm 10y agoRP-1/LOX also exhausts basically water vapor, plus CO2. There should be little NOx emission since it's not burning air, but there's probably some organic emissions from unburned fuel.
- coryfklein 10y agoIs it? I know very little about rocket fuel, but I always assumed that CO2 is involved. A short bit of Googling "composition of rocket fuel exhaust" wasn't immediately helpful. :/
- azernik 10y agoOther responses go into this in more detail, but basically there are a few very chemically different types of rocket fuel. Usually for main engines these are bipropellants, with a fuel component and an oxidizer component. The expensive, exotic, high-specific-impulse, but low-density and dangerous option is liquid hydrogen + liquid oxygen (hydrolox), which does indeed create water vapor as exhaust. This particular rocket, however, uses RP-1 (similar to jet fuel - just highly refined kerosene) + liquid oxygen - still burning hydrocarbons, still releasing CO2, but favored because it's cheap, dense, safe, and doesn't need cryogenic cooling. For comparison, the ITS (and many other Mars mission concepts) use liquid methane + liquid oxygen (methalox), which also outputs CO2, needs cryogenic cooling and is not as safe or dense as RP-1/LOX, but is still safer and denser than hydrogen, doesn't need to be kept quite as cold, and is easy to synthesize on-site on another planet.
- wiredfool 10y agoAnd then there are the more out-there toxic ones like hydrazine and whatever fuel they use with oxidizers like nitric acid and the chloroflourines.
- skookumchuck 10y agoJust look at the composition of the rocket fuel, and add oxygen to that. It the fuel has lots of carbon atoms in it, CO2 will be the result in the same proportion.
- homerowilson 10y agoMostly CO2 and CO, see for instance https://en.wikipedia.org/wiki/RP-1 https://en.wikipedia.org/wiki/RP-1
- Retric 10y agoThe H in hydrocarbons mostly ends up as water, so ideally it's about 50/50 H2O + CO2. But, you do get a little bit other stuff. https://en.m.wikipedia.org/wiki/Kerosene https://en.m.wikipedia.org/wiki/Kerosene The combustion reaction can be approximated as follows, with the molecular formula C12H26 (dodecane): 2 C12H26(l) + 37 O2(g) → 24 CO2(g) + 26 H2O(g); ∆H˚ = -7513 kJ
- schiffern 10y agoIt's about 50/50 by moles, but one mole of CO2 masses 44/18th = 2.44x as much as one mole of water. The atomic makeup of RP-1 is about CH1.97[1], so at stoichiometric ratio[2] that would yield 71.3% CO2 and 28.7% H2O by mass. [1] http://www.qrg.northwestern.edu/projects/vss/docs/propulsion/3-what-are-some-rocket-propellants.html http://www.qrg.northwestern.edu/projects/vss/docs/propulsion... [2] in reality Falcon 9 burns fuel-rich
- lftl 10y agoAs an interesting bit of trivia: the most prevalent greenhouse gas in the atmosphere? Water vapor.
- DennisP 10y agoWhich doesn't mean that emitting water vapor from a rocket adds to global warming. It just adds to the rain.
- morsch 10y agoTrue as long as you intend to fly your rocket within the troposphere, the lower ~10 miles of the atmosphere. Above that, water vapor seems to stick around a long time and is currently understood to be quite harmful[1]. This is also an issue with high-flying planes (not that flying low is better, due to the decreased efficiency). However, more research is needed[2]. [1] http://www.grida.no/publications/other/ipcc_sr/?src=/climate/ipcc/aviation/076.htm http://www.grida.no/publications/other/ipcc_sr/?src=/climate... (kind of old, but I think the more recent IPCC reports are in a similar vein) [2] https://eos.org/research-spotlights/the-forgotten-water-vapor-at-high-altitudes https://eos.org/research-spotlights/the-forgotten-water-vapo...
- DennisP 10y agoWow, learn something new every day. Thanks!
- morsch 10y agoDoesn't really matter what it exhausts, it expends energy either way. If it ran on hydrogen, you'd probably have to use electrical energy to produce that. Even if you somehow got the hydrogen "for free", there are other things you could use it for. This is all quite separate from the moral issue, to which I have nothing to add.
- coryfklein 10y ago> Doesn't really matter what it exhausts, it expends energy either way. Energy usage is not the only consideration, and it certainly does matter what it exhausts. Exhausting an inert gas is definitely preferable to a greenhouse gas, which would be preferable to exhausting anthrax, etc. The composition of the exhaust is going to affect the positivity of the public reaction to a billionaire burning it into public air space for leisure.
- hamandcheese 10y ago> the moral issue Uhh, what moral issue, exactly?
- netcraft 10y agoOr you can look at it like someone is bankrolling a significant trial of several potentially species saving technologies. (I understand you're playing the devil's advocate, just trying a response)
- ctdonath 10y agoThe flight is a necessary step toward viable interplanetary travel. Even NASA slung people around the Moon before later flights landed thereon. Gotta send a rocket up & around & back, with passengers, to make progress toward the "colony on Mars" goal, so may as well do it with someone willing to fund a good chunk of the excursion.
- rwmj 10y agoI actually think today we'd be in a better situation if NASA had stopped there and didn't land on the moon (in the 1960s). Here's my reasoning: (1) It's much easier to orbit the moon than to land on it. (2) Both the US and the USSR had the capability to send many people on orbital flights around the moon. (3) With both the US and USSR orbiting the moon, the space race wouldn't have ended (because both had the same capability and neither had put a flag on the surface). (4) Once both countries are orbiting the moon for a few years, at some point in the 1970s one or the other would have made a landing. (5) Both great powers would be competing incrementally in the same space, but at the same time it's not a situation which could have plausibly lead to a war, so it would have been safe for humanity.
- rimantas 10y ago1) It is much easier to stay on Earth than to got into space 2) All the nations have a capability to stay on Earth …
- chris_va 10y agoInterestingly, the Falcon Heavy has similar fuel capacity to a 747. (plus or minus)
- Symmetry 10y agoWell, 215,000 L for the 747, 175,000 L for a Falcon 9, and 470,000 for the Falcon Heavy so in the same rough range. The Falcon Heavy is also carrying another 780,000 L of oxygen but that doesn't contribute any extra carbon, of course.
- mulmen 10y agoThat is a really surprising comparison, thanks for pointing it out! Do you have a source for that, it is something I expect to be repeating.
- TeMPOraL 10y agoI agree. For some reason I imagined that orbital-capable rockets use order(s) of magnitude more fuel than airliners...
- prewett 10y agoDepending on how you count, it does. The 747-8 freighter can carry 240k L of fuel [1], and 308k lbs of cargo [2], so 1.3 L/lb. The Falcon Heavy can launch 120k lbs of cargo into low-Earth orbit [3], and according to the grandparent, is carrying 1250k L of fuel (including oxygen, which is an essential component of "fuel" in this case), so 10.4 L/lb. Still, that's better than I expected. And if you want to go to Mars, you can take 30k lbs, so 41.7 L/lb, for only 4X LEO, quite the bargain! (Interestingly, the average cost of a 10 hr 747 flight is about $40k [about $14k for fuel, which is about 33% of costs], compared to $90m [estimated] for a Falcon Heavy launch. So one order of magnitude more fuel, but almost 4 orders of magnitude more price.) [1] https://www.reference.com/vehicles/much-747-weigh-8b0c48a1d8ffd41a https://www.reference.com/vehicles/much-747-weigh-8b0c48a1d8... [2] https://en.wikipedia.org/wiki/Boeing_747-8 https://en.wikipedia.org/wiki/Boeing_747-8 [3] https://en.wikipedia.org/wiki/Falcon_Heavy https://en.wikipedia.org/wiki/Falcon_Heavy [4] https://www.quora.com/How-much-fuel-does-a-Boeing-747-or-777-consume-per-hour-while-in-flight-and-what-is-the-approximate-cost-of-that-fuel-for-the-airline https://www.quora.com/How-much-fuel-does-a-Boeing-747-or-777... [5] https://www.quora.com/How-much-of-the-cost-of-an-airline-ticket-is-based-on-the-price-of-fuel https://www.quora.com/How-much-of-the-cost-of-an-airline-tic...
- paulddraper 10y ago> I also think that spending money on a roundtrip to the moon is way better for humanity than spending it on champagne, caviar and cars. How? I'm not saying you're wrong, but gut instinct is that automobiles are more useful to humans. I'd like to hear your thought process.
- Mithaldu 10y agoFair question. In short: Unless you're buying Tesla your car expenditures won't fund any significant research into improving cars in a way that benefits humankind.
- briandear 10y ago[citation needed]
- Mithaldu 10y agoI'm happy to be corrected if you know more.
- mikestew 10y agoYou're the one that made the claim, it not up to the rest of us to post links refuting it.
- Mithaldu 10y agoYes, i made the claim, however i don't stand by it. I was challenged, realized my knowledge may not be up to snuff and asked that someone more knowledgable than me be nice enough to share, and i meant that earnestly. I'm not interested in winning contests, i just want to have good knowledge. clock_tower did so here, very excellently: https://news.ycombinator.com/item?id=13749603 https://news.ycombinator.com/item?id=13749603
- clock_tower 10y ago
- chatterbeak 10y agoQuite a few jobs are created by demand for champagne, caviar, and cars. And also jobs with living wages for farmers, fishermen, production line workers, drivers, and even engineers. While I'm all for space exploration, I wouldn't make any judgement calls on what activities are "better" for humanity.