North America was recently graced with a total  solar eclipse.Those of us lucky or obsessed enough   to be on the narrow path of totality and … also  lucky enough to not be under a giant blanket   of clouds … witnessed this most wondrous of  all celestial phenomena.

The Sun went dark,   the solar corona blazed, and even the ruby-red  top of the solar atmosphere became visible to   the naked eye.

Jupiter, Saturn, Venus, and even  a comet straddled the new black-hole Sun.

Part of   the reason the total solar eclipse is special is  that it’s so rare.

If it happened every day you   probably wouldn’t even look up.

Well, good  news for those of us who missed the eclipse,   whether due to weather or geography there is such a phenomenon.

It’s that enormous ball of rock that’s just hanging in   our sky.

The one that happens to be the exact size to blot out the Sun now and then, and without which we   may never have figured out how the universe  works—or begun our exploration of it.

It’s   the Moon, and it’s our stepping-stone to the  universe.

Today we learn how to take that step.

INTRO MUSIC Seriously, our Moon is crazy.

You know those over  the top science fiction sky-scapes—multiple suns,   multiple moons, gigantic moons or Saturn-like  planets or crazy nebulae that fill half the   sky.

The reason we have to come up  with that stuff is because our own   sky is already pretty sci-fi over-the-top.

No  other planet in our solar system has anything   like the Moon.

The only physically larger natural  satellite are 3 of Jupiter’s and one of Saturn’s moons,   and our Moon is still comparable to those in  raw size.

But the gas-giant moons are tiny   compared to their host planet.

Our Moon is  by a long, long way the largest relative to   the planet it orbits, making the Earth and  Moon practically a binary planet system.

It’s generally believed that our  moon formed when a Mars-ish-sized   planet that we call Theia slammed  into the still-forming Earth,   throwing up one of those sci-fi planetary  rings that quickly pulled itself together   into the Moon.

And we’ve talked about this  hypothesis before.

That seems   like a rare enough event that some argue that such  outsized moons are probably rare in the cosmos.

If so, then an alien looking up at our sky would  be like what the hell is that thing?

And then   they might think that it’s no wonder these  otherwise primitive humans were so quick to   figure out so much about the universe from  the big bang to the end of time.

I mean,   we could only pretend that we are at  the center of a small universe for so   long when we can literally see the detailed  surface of another world with the naked eye.

The Moon is both our metaphorical and literal  stepping stone to the universe.

I’ll come back   to the literal part in a minute—let me  just drive in the metaphorical part a bit   harder.

The Moon gives us a few telling  clues about our place in the universe.

1) It's round.

The moon is pretty clearly a  giant ball of rock with a cratered surface.

It’s a world.

Surely an essential clue  that the other bodies of the solar system,   including the Earth, are of similar form.

2) Its eclipses and lunar phases.

We saw this  last episode.

These phenomena told us the basic   structure of the Earth-Moon-Sun system, but  also allowed us to figure out the distances   to the Sun and Moon—our first hard calibration  of the immensity of space.

And watching the   Earth’s round shadow cross the Moon really  drilled in the whole Earth isn’t flat thing.

3) The Moon's gravitational attraction to Earth.

It’s said that Isaac Newton figured out   his law of universal gravitation after  watching an apple fall.

But the other   part of the story is that to figure out  the relationship between gravitational   force and distance he needed a much more  distant object that is also subject to   Earth’s gravity.

He used the Moon.

Without the  Moon it may have taken much longer to figure   out gravity.

And without that don’t even  think about starting up a space program.

So the Moon has been one of the most important  theoretical stepping stones to our understanding   of the universe.

And we’ve long understood that it could also be our literal stepping stone:   It is humanity’s first destination beyond our  atmosphere.

Through   the Apollo programs humans walked on another world.

The last time that happened was over   half a century ago.

It’s no longer something we  do; it’s something we did—like, back in history.

It’s been argued that we no longer need to  put people on the Moon.

We got all the rocks,   that particular cold war ended.

And perhaps  most importantly we convinced ourselves that   inter-world travel is possible.

Our eyes became  fixed on Mars as the next human destination.

But can you imagine us even contemplating  a trip to Mars without having first landed   on the Moon?

Thanks Moon—job well  done.

Please continue your regular   duties of sloshing our oceans and making  the night a bit more romantic and moon-lit.

Except, are we really done with the Moon?

In recent years our collective intentions   have swiveled back to the great sky rock.

Just last month, the very first private   company achieved a soft landing on the  Moon.

Intuitive Machines managed to touch   down its Odyseus lander about 300km from the  lunar south pole and took spectacular images   of the surface and gathered important  data for future missions.

The soft   landing could’ve been softer because  Odysseus tipped over on touch-down,   which did shorten its life expectancy but  didn’t dent its overall success.

This was   such a major achievement because the lunar poles  are more heavily cratered than the equator,   and experience extreme temperature fluctuations  that landers have to be resilient against.

Intuitive Machines didn’t just achieve  the first private softish landing;   this was the first soft landing by the  United States in the 52 years since Apollo   17.

But our return to the Moon has been  building up momentum for some years now.

In August last year India became only the 4th  nation to soft-land on the Moon.

Its Vikram   lander, part of the Chandrayaan-3 mission, was  also the first craft to land in the lunar south   pole region where it successfully deployed  its Pragyan rover to explore the area..

But why this current obsession with the lunar  south pole, if the poles are so hazardous?

Well,   because of a game-changing fact that India’s first  moon mission—-Chandrayaan-1—helped establish.

It   found water at the south pole.

Back in 2008,  Chandrayaan-1 dropped its Moon Impact Probe   into the Shackleton Crater.

The “hard-landing”  craft detected significant water in the tenuous   south pole atmosphere its descent, confirming  earlier evidence from a number of other missions.

To be clear, these detections are not quite  direct, and require interpretation.

There’s   strong evidence for hydrogen in  the tenuous lunar atmosphere,   likely from actual ice or water or  hydroxil bearing minerals in the soil,   and direct detection of those minerals.

We’ve  also known for a while that there was real water   ice in the permanent shadows of some lunar  craters.

But there’s an emerging consensus that   there must be significant ice even in sunlit lunar  soil.

That means there’s just way more water than   we thought.

It’s not even clear how it got there.

Perhaps it was brought in by comets, just like   Earth’s oceans might have been.

Or perhaps  protons in the solar wind slam into oxygen   in lunar minerals to produce H2O.

There’s some  evidence that that lunar surface water is being   continuously replenished, so the latter may well  be important.

Whatever the source, the presence   of water turns the moon from a pretty but dead  sky rock into our stepping stone to the stars.

If you’ve spent any time in Arakis you  know why water is such a game changer.

Although it’s abundant on Earth and  Caladan, it’s heavy and so expensive   to pull out of a gravity well.

It costs a  couple of thousand US dollars to get every   litre of water to the international space  station, let alone to the moon.

Even with   Fremen Stim-suit level water recycling, good  luck building a decent sized base, let alone   even a small biosphere.

But an  enormous lunar source makes all of this possible.

Which brings us back to human plans for the Moon,  and to China.

China has been vigorously pursuing   lunar exploration for longer than India with its  uncrewed Chang’e program.

Chang’e-3’s successful   2013 landing made China the 3rd nation to achieve  a soft landing after the US and Russia efforts   both ended in the 70s.

Chang’e-4 was the first  anything to land on the far side of the Moon in   2019, and Chang’e-5 the first non-crewed lander  to successfully return lunar material to Earth.

That was in 2020.

The next Chang’e - number 6 -  is supposed to launch next month and to return   samples from the apparently watery south pole.

Number 7 will also mess around at the south pole,   but number 8 … Chang’e-8 will do a 3-D printing  experiment using lunar regolith and will carry   a sealed ecosystem experiment.

All in preparation  for the next phase—a crewed lunar base.

China aims   to land humans on the Moon by 2030 and  by 2035-ish to establish a permanent   base in collaboration with Russia, but  ostensibly as an international facility.

The United States may have been the first, and  still the only nation to put a human on the Moon,   but has been distracted by another shiny  thing in the sky.

NASA’s space exploration has   really been focused on Mars—and with excellent  reason.

Besides being the next obvious human   destination after the Moon, we’ve known for much  longer that Mars has water—both to support a base   but also perhaps to once have supported life.

The  impact of finding evidence of that would be much,   much bigger than even the first Moon  landing, in my opinion.

The Moon could   never have evolved life, but with water  it could support our life in the future.

And so again the United States is  finally turning its eyes back to   the Moon.

The Artemis program aims to  send crewed missions on the Moon—first   in orbit and then to the surface.

It consists  of the Space Launch System—a super-heavy lift   rocket—carrying the Orion spacecraft.

Other  vehicles will also serve the larger Artemis   mission, like the SpaceX Falcon heavy carrying  the Dragon spacecraft.

In 2022 the un-crewed   Artemis 1 mission put an Orion spacecraft into  lunar orbit before successfully returning it   to Earth.

In 2025 Artemis 2 will do the  same, but with people—four astronauts.

And then in 2026 Artemis 3 aims to put the first  American boots on lunar soil since Apollo 17.

The other big goal of the Artemis program is the  construction of the Lunar Gateway space station—a   crewed station that will be constructed in lunar  orbit over the rest of this decade.

This one is   with participation of the Canadian, Japanese,  European, and Dubai space agencies.

There has   been some criticism of Gateway—basically amounting  to the question of why build a station in orbit   when you could build a station on the Moon.

Fair point, but ultimately the US is planning   to build a surface base, and the Gateway  station is supposed to support that goal,   as well as be a general staging station  for a variety of solar system missions.

Speaking of, there’s something else that  lunar water is good for.

Apply an electric   current to H2O and the molecule splits giving  you hydrogen and oxygen.

This is electrolysis.

These gases very readily recombine into  H2O, releasing the same energy it took to   separate them—but now explosively.

Like, in  a rocket.

Water can be used to make rocket   fuel.

The idea would be to place some giant  solar arrays on the surface near the poles   and use the energy to slowly harvest hydrogen and  oxygen, turning the Moon into a refueling depot.

The weight of fuel is one of the biggest limiting  factors in determining spacecraft weight and   range.

And dragging that fuel out of Earth’s  prodigious gravitational well is the hardest part.

With a lunar fuel depot, the most fuel any mission  needs to carry is the amount needed to reach the   Moon.

From there it can be refueled for its onward  journey to Mars, the asteroid belt mines, its   return to Earth, or perhaps to some destination  beyond the solar system.

And sure, I guess being   able to dock at the Lunar Gateway is better than  having to land on the Moon before moving on.

If all goes according to the various plans,  in as little as 10 years we’ll have our first   deep-space space station, our first crewed lunar  base.

Maybe a couple of them.

And we’ll be working   towards the ability to refuel spacecraft from  lunar orbit.

There are plenty of other plans   also—like the giant radio telescope on the  far side of the Moon that we talked about   previously.

For the most part our return to the  Moon seems like a positive thing, with lots of   international collaboration to build a shared  and peace-forward infrastructure.

For example,   the US just announced a move to create an  internationally agreed Lunar Standard Time   to account for the fact that time ticks a tiny bit  slower on the Moon compared to Earth’s surface on   account of general relativity.

But there are  signs of competition already arising, and the   whiff of a new space race in the air.

China versus  the US seems to be the main superpower standoff,   with each asserting their leadership.

Russia is  aligning more with China, Europe with the US,   and various nations sidling in one direction  or the other.

And then there’s the private   sector which will play increasingly large, if  not dominant part of the game going forward.

Whatever the outcome, it’s coming, and pretty  fast.

Odds are that in the decade—perhaps much   quicker—somone will be back on the Moon or close to it.

And probably that someone will be human,   which is a win for all of us.

We’ve been snoozing  a bit on the Moon, but soon we’ll be walking on   it.

Again.

And hopefully soon after, that  weirdly giant sky rock will fulfil its   potential as a fortuitous stepping stone towards  our future exploration of the rest of space time.