If We Can Put a Man on the Moon, Why Can’t We Put a Man on the Moon? • Hacker News Board

Re: If We Can Put a Man on the Moon, Why Can’t We Put a Man on the Moon?

#61

Post by bonesss » Tue, Jan 02, 2018, 12:09 PM UTC

gozur88 wrote: post #13

abecedarius wrote: post #9

Earlier quoted context omitted.

Lunar resources could have great value just by their location. The energy cost to lift them into space is much lower than from Earth. Doing anything ambitious in space would require a lot of material, which has limited our ambitions since the 1970s. (Asteroids might serve better, though: a wider variety of stuff, comparable in energy cost but farther away.) I wish the damn article would link to this new report, or at…

>Doing anything ambitious in space would require a lot of material, which has limited our ambitions since the 1970s. We go to the moon because materials are cheap because... we want to build what?

A giant radio telescope on the 'dark side' of the moon to let us peer into the depths of time without interference from the noisy monkeys in unit 3a ;)

Ships, structures, and anything heavy that we could avoid pulling out of earths gravity well would be big cost savers if we're putting around the solar system or putting up shop anywhere.

There are also some high-energy applications that could get dicey on earth but wouldn't be too bad to setup on a neighboring geographic area with no atmosphere or food chain to worry about.

Oxygen generators, habitats, water refiners, nuclear reactors... Ideally from autonomous building robots, these would be the foundation of long term habitation.

Re: If We Can Put a Man on the Moon, Why Can’t We Put a Man on the Moon?

#62

Post by bonesss » Tue, Jan 02, 2018, 12:15 PM UTC

make3 wrote: post #36

solatic wrote: post #25

Earlier quoted context omitted.

That's like going back to the 17th century and decrying the exploration of the New World because you're not certain just how much gold there may be and you can't predict what the New World economy might look like. Barring drastic efficiency increases in launch technology (to a Star Wars style level of ease) a lunar base is essential to enabling a space economy not suffocated by heavy shipping and transaction costs in…

Except that back then they couldn't see what was in the new world. Now we can (on the moon), and know that there isn't much. Also, it would take a lot more than just sending people there for them to be mostly be self sufficient like in the 17th century, because: - there is no oxygen, - there is no food, - there is no water, - there is no magnetosphere.

We can make [oxygen from moon rocks](https://phys.org/news/2009-08-scientists-oxygen-moon.html).

There is [water on the moon](https://www.nasa.gov/mission_pages/Mini-RF/multimedia/featur...).

With oxygen, water, and power, we can make food.

Appropriate radiation shielding is a matter of construction, which could occur on the moon itself using local materials ideally, or building underground enough to be shielded.

Moon habitation is something that makes little sense for its own benefit, but immense sense in an orbital supply chain for... I dunno... harvesting a few trillion dollars worth of minerals.

Space exploration will not be easy. Navigating accurately across thousands of miles of ocean on [a homemade raft](https://en.wikipedia.org/wiki/Polynesian_navigation) with only a coconut named Wilson and your hands isn't easy either :)

Re: If We Can Put a Man on the Moon, Why Can’t We Put a Man on the Moon?

#63

Post by bonesss » Tue, Jan 02, 2018, 12:23 PM UTC

perilunar wrote: post #52

RikNieu wrote: post #45

Earlier quoted context omitted.

How would one produce low gravity on earth?

Two methods: the vomit comet [1], and shot towers [2]. 1. https://en.wikipedia.org/wiki/Reduced-gravity_aircraft 2. https://en.wikipedia.org/wiki/Shot_tower

You want to put a delicate-cable factory on an airplane and figure out how to shape all materials from start to finish in 30-second bursts while also compensating for turbulence, additional Gs on ascend, flight adjustments, and proper stowing for takeoff and landing? ...

Oddly, that's the more practical of those suggestions, because forming a few kilometers of perfect glass by letting it cool while dropping would seem to require a tower impressive in its own right... More relevant, there are QA demands with fiber-optics that don't seem to jive with a "let it hit the ground and throw out the lumpy ones" approach, much less the handling while in full gravity (which is where the issues are).

Re: If We Can Put a Man on the Moon, Why Can’t We Put a Man on the Moon?

#64

Post by JeanMarcS » Tue, Jan 02, 2018, 12:41 PM UTC

kalleboo wrote: post #59

Al-Khwarizmi wrote: post #50

This seems to happen to a lot of things. In my city (random Spanish mid-sized city, around 250K population) there is often debate about building a light rail or tram public transport line. But it is always dismissed by the administration for being too expensive, pharaonic, disproportionate for a city of this size, etc. Doing some research on the history of the city, I discovered that not only there were several tram…

I lived in a Swedish city of a similar size. They had a tram network that was dismantled bit by bit until it was completely shut down in 1973 because it was seen as unmodern. And now 40 years later they're all talking about building trams again since they're so modern...

In Marseille,France there was a tram when I was young (mid 80’s). They dismantled it. Then build it back in the 2000’s...

Re: If We Can Put a Man on the Moon, Why Can’t We Put a Man on the Moon?

#65

Post by adrianN » Tue, Jan 02, 2018, 1:23 PM UTC

BonsaiDen wrote: post #23

gozur88 wrote: post #13

Earlier quoted context omitted.

>Doing anything ambitious in space would require a lot of material, which has limited our ambitions since the 1970s. We go to the moon because materials are cheap because... we want to build what?

Factories in Orbit, pretty much. There might not be many products today which will benefit from this ability, but a free fall environment brings many benefits to things such as crystallization of materials. For example, the last resupply mission of Space X to the ISS included an experiment to product optical fibers onboard the space station, the goal is that these fibers will have a much lower number of defects in th…

Getting to Moon orbit from the Moon is also much easier that getting in LEO.

Re: If We Can Put a Man on the Moon, Why Can’t We Put a Man on the Moon?

#66

Post by adrianN » Tue, Jan 02, 2018, 1:25 PM UTC

olalonde wrote: post #41

sillysaurus3 wrote: post #12

Earlier quoted context omitted.

Because it's awesome. :) I mean, we burn piles of money just for fun. May as well burn a pile of money to put someone on the moon again. Doing it just because we can is a fine reason. "Still got it!" One tweak, though. Rather than forcing them to find a reason to go, i.e. gathering moon rocks, they should just let the astronauts play around. That's the goal. Go there, then turn on a webcam and romp around for a few d…

> That would get the world thinking. It might get some baby boomers excited but I'm not sure about younger generations. It doesn't feel like an exciting, impossible mission today.

The next step is of course a permanently inhabited base on the Moon. That feels like an exciting mission.

Re: If We Can Put a Man on the Moon, Why Can’t We Put a Man on the Moon?

#67

Post by toyg » Tue, Jan 02, 2018, 1:35 PM UTC

Al-Khwarizmi wrote: post #58

jpatokal wrote: post #54

Earlier quoted context omitted.

Classic trams and modern light rail are different beasts. Trams were popular worldwide back in the days where automobiles were far too expensive for most people and buses hadn't taken off yet, and since they were the only practical means of transport for medium distances, even small cities had massive ridership. They also ran right on the road, sharing space with cars, which was OK because there were a lot less cars…

Yes, that's a very good summary of what happened. I'm aware of those factors, but I still think we took a wrong turn. Maybe not in the US due to the population sparsity and sprawl, but in Spain and many other European countries, if we could connect every town or city of more than 10K people by either rail, light rail or tram (instead of having spent billions on highways), that would cover 80% of the population. A lar…

If it can make you feel better, I know a lot of Italian cities are going back to trams in dedicated lanes. This is on the back of the clear advantages enjoyed by those cities (Rome, Milan) who didn't actually rip out all tracks after the last war.

There is an element of busywork too: local officials are always elected by promising change, they have to be seen doing something. So on odd years they put in something, and in even years they take it out...

Re: If We Can Put a Man on the Moon, Why Can’t We Put a Man on the Moon?

#68

Post by GCU-Empiricist » Tue, Jan 02, 2018, 1:42 PM UTC

maccam94 wrote: post #53

T-A wrote: post #38

Edit: nope, looks like it's this one: "Stepping Stones: Economic Analysis of Space Transportation Supplied From NEO Resources" https://www.nasa.gov/sites/default/files/atoms/files/eso_fin... --- I think the report in question is "NASA's In Space Manufacturing Initiatives: Conquering the Challenges of In-Space Manufacturing": https://ntrs.nasa.gov/search.jsp?print=yes&R=20170011108 These may also be interesting: "NASA…

I really want to see asteroid mining prioritized, as well as a space station capable of permanent human habitation (either partial or full gravity). A space station is also preferable to another planet for our next big space endeavor IMO because it is easier to get materials to and from it (no extra gravity well to deal with). Also, I feel like a lot of people think "ah, everything has to be done differently because…

It'll happen when there's a business model that reduces the operating margin for a company. My best guess is this will be when the price for lithium or trans-uranics goes up significantly, or some engineering process requires microgravity conditions.

Re: If We Can Put a Man on the Moon, Why Can’t We Put a Man on the Moon?

#69

Post by Klathmon » Tue, Jan 02, 2018, 1:47 PM UTC

maccam94 wrote: post #49

Animats wrote: post #43

Because, half a century later, it's not any cheaper to do it than it was then.

It's recently gotten way cheaper. Cost per kilogram delivered to LEO: Saturn V (used for the Moon landing mission): $8,250 Falcon 9: $2,700 (price for an expendable launch) BFR (hypothetical, in development rocket): $500

Does that scale to a full lunar mission though?

Just because it's cheaper to take the bus downtown doesn't say anything about the cost of airfare to another continent.

Re: If We Can Put a Man on the Moon, Why Can’t We Put a Man on the Moon?

#70

Post by sytelus » Tue, Jan 02, 2018, 1:51 PM UTC

maccam94 wrote: post #49

Animats wrote: post #43

Because, half a century later, it's not any cheaper to do it than it was then.

It's recently gotten way cheaper. Cost per kilogram delivered to LEO: Saturn V (used for the Moon landing mission): $8,250 Falcon 9: $2,700 (price for an expendable launch) BFR (hypothetical, in development rocket): $500

In inflation adjusted dollars? I would have still thought its 10X cheaper now because of all the learnings plus much lower cost computing and other engineering enhancements.

Back in 1973, the total cost of the Apollo program reported to Congress was $25.4 billion. By far the most expensive parts of the mission were the Apollo spacecraft (the Command Modules, the Lunar Modules) and the monstrous Saturn V launch vehicles. A single Saturn V launch cost up to $375 million in 1969 — or, in today’s money, a few billion dollars.

In 2009, NASA looked back at the cost of the Apollo program in its entirety, and arrived at a figure of $170 billion in 2005 dollars (or around $200 billion in today’s money). Compare these costs to modern day space travel, where companies like SpaceX charge just $133 million to launch a spacecraft to the International Space Station. The Falcon Heavy, which will be comparable to the Saturn IV, will be in the same price region.

https://www.extremetech.com/extreme/186600-apollo-11-moon-la...