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Water Found Deep Inside the Moon

news.nationalgeographic.com

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Re: Water Found Deep Inside the Moon

#211

Post by erikbye »

seanp2k2 wrote: post #19
nolok wrote: post #13

Earlier quoted context omitted.

> I can't imagine how much crazier ads have been getting I would certainly argue the way this comment (and many others in a lot of threads about ads here or elsewhere) seems to imply that ads are at their worst ever. I mean either people forgot or are too young to remember, but in the 2000's alone ads had both their "pop up and sound and unclosable javascript spam" and their "flash everywhere turning your modern supe…

Ads were terrible, they continue to be terrible, they used to and still do provide most of the money needed to run sites, and it's still hard to get users to pay for content like articles on the internet. We still haven't solved these fundamental problems with funding quality content on the web. There are models that kinda work, but ads sadly seem to work the best in terms of giving everyone access "without paying",…

I subscribe to a lot of sites and newspapers and they still show me their ads.

Re: Water Found Deep Inside the Moon

#212

Post by computerex »

ChuckMcM wrote: post #189
Robotbeat wrote: post #172

Earlier quoted context omitted.

It's questionable that it's really much lower cost. The Moon, as a vacuum body, doesn't give the option of aerobraking or atmospheric entry, which dramatically reduces delta-V. You can get a payload to Mars' surface with less propellant than getting it to the Moon's surface. And because atmosphere is everywhere (which includes oxygen in the form of CO2 and also water vapor), propellant is way easier to make, so it's…

Per glindahl's comment from earlier, if we established a space elevator for the moon[1] it would make the delta-v issues moot. Drop off an pick up supplies at the elevator while swinging by on an continuous Earth/Moon translunar orbit. [1] https://en.wikipedia.org/wiki/Lunar_space_elevator

The space elevator even on Earth in GEO is a hopeless, fool's dream.

Re: Water Found Deep Inside the Moon

#213

Post by [deleted] »

Abishek_Muthian wrote: post #210

"In 2009, NASA crashed a rocket and a satellite into a crater on the moon’s south pole, in the hopes of picking up additional watery evidence. " NO, In 2008 ISRO crashed Moon Impact Probe (MIP) into lunar surface as part of Chandrayaan-I mission. MIP didn't have any specific role, other than political agenda. The NASA's Moon Minerology Mapper M3 onboard of the Chandrayaan spacecraft was instrumental in providing the…

[deleted]

Re: Water Found Deep Inside the Moon

#214

Post by nine_k »

computerex wrote: post #212
ChuckMcM wrote: post #189

Earlier quoted context omitted.

Per glindahl's comment from earlier, if we established a space elevator for the moon[1] it would make the delta-v issues moot. Drop off an pick up supplies at the elevator while swinging by on an continuous Earth/Moon translunar orbit. [1] https://en.wikipedia.org/wiki/Lunar_space_elevator

The space elevator even on Earth in GEO is a hopeless, fool's dream.

On Earth, it's hard to build due to much higher gravity, higher required orbit, and the atmosphere. Getting much shorter lengths of much less strong fiber to Moon may be more realistic than 20.000 km of super strong carbon fiber to GEO.

Re: Water Found Deep Inside the Moon

#216

Post by sevenfive »

fastball wrote: post #151
boznz wrote: post #134

Earlier quoted context omitted.

"Carbon, Nitrogen, Phosphorus, and Sulfur are only present in trace amounts" Is this because we havent found them yet, an educated guess or the moon somehow gets rid of these?

It's because the Moon lacks an atmosphere. CO (and then CO2) form at high temps, so elemental carbon doesn't have much chance to condensate to a "rock" form in regards to non-stellar celestial bodies. These float off into space, no atmosphere to contain them. At the temperatures/pressure of the moon, Nitrogen rapidly boils off and floats away as well. Not sure about Phosphorus and Sulfur, but I'm sure they can be eit…

Wut? Pretty sure phosphorus never goes atmospheric

Re: Water Found Deep Inside the Moon

#217

Post by hoorayimhelping »

passivepinetree wrote: post #180
Robotbeat wrote: post #172

Earlier quoted context omitted.

It's questionable that it's really much lower cost. The Moon, as a vacuum body, doesn't give the option of aerobraking or atmospheric entry, which dramatically reduces delta-V. You can get a payload to Mars' surface with less propellant than getting it to the Moon's surface. And because atmosphere is everywhere (which includes oxygen in the form of CO2 and also water vapor), propellant is way easier to make, so it's…

Your assertion about getting to Mars with less propellant is super interesting. Can you provide a source for me?

fewer than twenty five seconds of googling: https://en.wikipedia.org/wiki/Delta-v_budget

From LEO to the surface of the moon is 5.9 km/s

From LEO to the surface of Mars is 4.1 km/s

Re: Water Found Deep Inside the Moon

#218

Post by pasbesoin »

Unless we settle our military confrontations (of varying degrees), any successful political entity is going to have to take a (sufficiently potent) position on the moon, first.

Unless it is willing to accept the circumstance of its sole continuation being off-Earth (Mars, in the near term). And has the belief that its off-Earth presence can continue and succeed in the absence of its erstwhile Earth-based counterpart.

Re: Water Found Deep Inside the Moon

#219

Post by keenerd »

simonh wrote: post #167
keenerd wrote: post #75

Earlier quoted context omitted.

The Martian atmosphere is next to worthless for aerobraking human-scale infrastructure. One of the most significant points in the Moon's favor is the (relative) ease with which a space elevator could be built. It doesn't need unobtainium, current structural materials are strong enough.

SpaceX have run the simulations and while Red Dragon is possible, there's no way they can adapt Dragon to land on the Moon without adding an extra stage. That difference is entirely down to Aerobraking. Even the thin atmosphere of Mars makes a huge difference. Anyone who plays KSP can confirm this for you, especially using the Real Solar System mod, though the same lessson is apparent even in the stock game.

Okay, I concede it is totally possible. After including Nasa's atmosphere model and some drag coefficients from super-sonic bullets, it looks like Red Dragon's aerobraking maneuver would take 1600 seconds, cover 4800km and leave them with 3600 meters of altitude. (Those supersonic drag coefs were what really made the difference since they are around 0.3 at hypersonic and rise to 0.6 as it slows.)

Re: Water Found Deep Inside the Moon

#220

Post by foxylad »

WalterBright wrote: post #68
rory096 wrote: post #56

Earlier quoted context omitted.

>The 50% figure is from memory, and upon further reflection is probably not quite right, so take it with a grain of salt. You're actually underestimating. Mars has an atmosphere, so spacecraft can use aerobraking to significantly reduce the delta-v required to get there. The moon has no such benefit — propulsion is required all the way to the surface. The advantage of the moon, of course, is that it's not limited to…

You need a far bigger (heavier) craft to get to Mars. You'll need years worth of food, water, air, you'll need radiation shielding, much more space per crewmember, more redundant systems and backups, etc. Look at the size of the Apollo.

For the journey, yes. But for permanent settlement, in both cases you'll need of the order of years-worth of supplies while you become self-sufficient.

Back on-topic, the discovery of water on the moon makes this more achievable there; otherwise Mars's resources might have actually meant less resources were required.

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