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> We are excited to announce that SpaceX has been approached to fly two private citizens on a trip around the moon late next year. They have already paid a significant deposit to do a moon mission.

Can't wait to hear who booked this trip! Definitely one of the coolest ways to spend a lot of superfluous money :)




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.


Not 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.


The 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.


I 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.


1) It is much easier to stay on Earth than to got into space

2) All the nations have a capability to stay on Earth


Or 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)


Interestingly, the Falcon Heavy has similar fuel capacity to a 747.

(plus or minus)


Well, 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.


That 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.


I agree. For some reason I imagined that orbital-capable rockets use order(s) of magnitude more fuel than airliners...


Depending 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-8b0c48a1d8... [2] https://en.wikipedia.org/wiki/Boeing_747-8 [3] https://en.wikipedia.org/wiki/Falcon_Heavy [4] 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-tic...


Would it be erreneous to say that no matter how 'green' our industries and power consumption on ground becomes, aviation and space flight would always require carbon based fuel?


An electric plane could be a possibility, depending on advancements in battery technology or power storage in general. Space flight would most likely require some kind fuel, at least in our lifetimes - so far we haven't found any other way to move mass in vacuum other than expelling propellant.

However, not all rocket fuel/propellant is carbon based, in fact, most aren't.


We may be able to develop better electricity storage to allow electric planes to be more practical than they currently are.

However, there's also a lot of interest in using biofuels for aviation, so you may see that in the mid-term future we're using carbon-based fuels but they're largely carbon-neutral.


If we can make renewable energy cheap enough it'll start making economic sense to synthesize fuel oil out of the air and water rather than mining it out of the ground, leading to no net carbon consumption.


Isn't the exhaust just water?!?


Not 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.


RP-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.


Well, not the SRB part.


Yeah, in both cases, the SRBs are the majority of the launch thrust.


Doesn'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.


> 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.


Even in the ideal case (inert gas, no anthrax rocket, the first stage duly recycled), the energy usage would remain as a consideration.

You may have a point regarding the public perception; don't really care to weigh in.


Water is a greenhouse gas too.


> the moral issue

Uhh, what moral issue, exactly?


As an interesting bit of trivia: the most prevalent greenhouse gas in the atmosphere? Water vapor.


Which doesn't mean that emitting water vapor from a rocket adds to global warming. It just adds to the rain.


True 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... (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-vapo...


Wow, learn something new every day. Thanks!


Mostly CO2 and CO, see for instance https://en.wikipedia.org/wiki/RP-1


The 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 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


It'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...

[2] in reality Falcon 9 burns fuel-rich


Is 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. :/


Other 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.


And then there are the more out-there toxic ones like hydrazine and whatever fuel they use with oxidizers like nitric acid and the chloroflourines.


Just 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.


Not with the fuels used by the Falcon rockets. They use LOX + RP1 (kerosene), rather than LOX + LH (which does produce water).


> 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.


The key phrase in this statement is "for humanity", not "for an individual".

Automobiles, while useful, are mostly a solved technology (unless you're buying Tesla or some other prototype, pushing-the-envelope model). Buying another one - or for that matter, making another typical automobile - has negligible marginal impact on advancement of technology. Taking humans to the Moon again - first time in 45 years - will have a huge impact both on our technological capacity as a species[0] and on the public's willingness to pursue those advancements.

Also, spaceflight is an immature area of knowledge, so one could argue that in general, each dollar put in it has more marginal benefit than the same dollar put into buying typical consumer goods.

--

[0] - Which is arguably not ever-increasing; we've pretty much lost the manned deep spaceflight capabilities with the end of Apollo program. There are practical details we need to rediscover, and those details will be important in efforts to put humans on Mars and elsewhere in the Solar System.


I believe the technology that will benefit humanity significantly is in the batteries.


That's why we need battery-powered rockets.

http://bart.volgers.eu/wp-content/uploads/2014/01/Dilbert-El...


Battery powered rocket, here you go: https://en.wikipedia.org/wiki/Electron_(rocket)


Fair 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.


A Lexus would do much of the same; Toyota's already got plug-in hybrids, and is working on hydrogen fuel cells.

(As for the other expenditures proposed above: real AOC Champagne supports the vineyards and traditional practices of the Champagne province of France; caviar... supports sturgeon fishermen? But consuming both together is just conspicuous consumption -- Champagne is a dessert wine. :) )


Thanks for the correction. Buy Toyotas then, folks, if you can't afford Teslas. :D


Already there. :)


[citation needed]


I'm happy to be corrected if you know more.


You're the one that made the claim, it not up to the rest of us to post links refuting it.


Yes, 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


What if it's Larry Ellison and Travis Kalanick?


At least it'll be nice to have them off the planet for a couple of weeks.


Can we not let them back? Make up claims about space rabies or something?


Maybe Richard Garriot wants to survey his property (https://en.wikipedia.org/wiki/Richard_Garriott#Other_accompl...) from near-lunar orbit. ;)



interestingly his wife was president of a (now failed) space tech company:

https://en.wikipedia.org/wiki/Escape_Dynamics


James Cameron? He seems to have a penchant for this stuff.


Probably not them, but it made me think of these two... https://story.californiasunday.com/mars-madness


It would be cooler if they donated it for sending more robots to Mars...


More practical, science-wise? Yes. Cooler? Definitely not.

Sending humans to space has a very important non-scientific factor - human emotions and imagination. It's an important driving force that's also necessary until we bootstrap a proper profitable market that'll do the driving.


> Can't wait to hear who booked this trip! Definitely one of the coolest ways to spend a lot of superfluous money :)

Imagine it ends up being some celebrity, like Leonardo di Caprio (who has shown interest in space IIRC) or Lady Gaga. Don't you think it would somehow tarnish the whole thing?


Why would a figure with so much PR fire power tarnish it? If anything it would put space exploration front and center for so many young and adolescence people.


Even if it was Justin Bieber? Instead of "One small step for the man...", we'd have Justin singing "baby, baby, baby..." to promote his latest album.


I think the image that is being tarnished here is yours... Imagine we aren't told who the astronauts are until a long time after the mission (the photos and video have their faces redacted or something) would the revelation that one of them was Mr Bieber really make it suddenly less of an achievement or 'tarnish' it?


I'd rather it not be Justin Bieber.

Either the rocket would blow up on the pad or it would never come back. ;)


Not Leonardo di Caprio, he will stay behind even though there is enough room for two people on that return vehicle.

Also, hopefully not Matt Damon.


But if it's Matt Damon, there's bound to be a much bigger mission to go rescue him, so, more progress.


It could be Elon.


Nah, if Elon is going somewhere, it's deeper underground with his giant bore.


Hopefully it isn't. In the event that something goes wrong, we need him here.


I suspect Elon is saving himself for his Mars mission in 2031.


I was thinking the same. Relevant xkcd https://what-if.xkcd.com/124/


[flagged]


Export restrictions.


I didn't realize Trump and Putin personally qualified as weapons of mass destruction, but I guess it makes sense in retrospect...




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