Hacker News Reader

Comment by TuringNYC | Hacker News Reader

Firstly - congratulations to the whole team on this achievement

I'm also curious

- Why the south pole of the moon? does it have an added significance vs other locations on the moon?

- Is a landing on the south pole more difficult to achieve? Seems so according to this article: https://www.reuters.com/science/why-are-space-agencies-racin...

View on HN

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

> It is of special interest to scientists because of the occurrence of water ice in permanently shadowed areas around it. The lunar south pole region features craters that are unique in that the near-constant sunlight does not reach their interior. Such craters are cold traps that contain a fossil record of hydrogen, water ice, and other volatiles dating from the early Solar System

I believe Chandrayaan 1 has detected water, but not sure if it was the first one to do so

The definitive discovery of Moon water came from Chandrayaan-1 which carried with it a NASA-provided science instrument called the Moon Mineralogical Mapper—M3 for short—that observed how the surface absorbed infrared light. Using this data, M3 determined that previously suspected water molecules were ice inside the Moon’s polar craters [0].

However, the first direct evidence of water vapor near the Moon was obtained by the Apollo 14 in 1971 [0]. A series of bursts of water vapor ions were observed by the instrument mass spectrometer at the lunar surface near the Apollo 14 landing site.

[0]: https://www.planetary.org/articles/water-on-the-moon-guide

[1]: https://en.m.wikipedia.org/wiki/Lunar_water

NASA LCROSS confirmed it before the Indian mission (which NASA instruments also on the Indian mission confirmed first). After NASA confirmed, Indian officials came out with their own announcement

Chandrayaan 3 landed at around 69 degrees south latitude which isn't far enough south to access the permanently shadowed craters where large ice deposits might occur (and the Pragyan rover uses solar panels for power).

I haven't read specific reasons for choosing that site, but we have never landed that far south, and it will be interesting to see what differences (if any) there are from the more central latitudes, which is a good enough reason on its own.

It may be due to communications problems if a lander came down in one of those shadowed craters. We would not be able to communicate with it. it would probably require relay satellites around the moon to mediate that communication.

Moon undergoes extreme temperature fluctuations from day to night, resulting in boil off. There are spots on the South Pole that never see sunlight, so it’s our best bet for finding large deposits of water (as ice).

The ice would also be pretty close to the Moon's peaks of eternal light[1] where you don't have to have your solar panels spend half of every month in darkness. So basically where you'd want to live on the Moon if you had to pick somewhere.

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

Isn't that also related to why the Lunar Gateway (the proposed space station component of the current Artemis project at Nasa) was proposed to be in a lunar polar orbit?

You can easily reach every spot froma polar orbit as the moon rotates under your orbit

It's 69° south, so it's not so much the south pole as the polar region. For reference, the major landmass of Antarctica starts around that point on Earth. McMurdo Station is at around 78° South.

Possible water which would be a giant resource for a permanent presence.

Reply on news.ycombinator.com