Chang'e 6 lunar sample return mission returns with samples from moon's far side
theguardian.comOne thing they seems to have got working fairly reliably is the lunar landing of the probe using image processing to guide the final approach and touch down. It seems to have worked well in this and the previous mission, there are videos on youtube of that.
https://youtu.be/wUju9-cckKA?si=nZFOCga10mnCA_vs
The other component is the autonomous docking of the return probe in lunar orbit.
Soviets have done a lunar sample return, but they had a probe that would lift off directly into a earth return trajectory, but that seems to have limited both the liftoff mass and the possible zones in moon from which it can lift off. This seems a much more complex mission than that.
Also some animated videos of the misson show a skip re-entry back to earth, don't know if it is the case during this particular flight.
Here's an article on DIMES, the system JPL developed in the early 2000s to address the problem of estimating horizontal velocity for the Mars landers:
https://robotics.jpl.nasa.gov/media/documents/DIMES-ai-space...
Martian winds make this more important there than on the Moon. The DIMES system integrates radar, visual images, and IMUs. They did not have a dedicated Doppler radar for horizontal velocity, for technical and cost reasons it was not workable.
From the introduction:
> Some of the challenges were subtler — and one in particular was subtle enough that it wasn’t fully appreciated until mission development was well underway.
> This was the challenge of martian winds. How to detect and compensate for them? In the worst-case scenario, they could tip the vehicle over in the final stages of descent such that the powered thrust intended to eliminate downward velocity might actually drive the platform sideways and down into the surface beyond the safety envelope of the airbag cushions.
> This article tells the story of how this late-understood challenge was addressed successfully — and, as it turned out, critically, for Spirit.
The system was improved and re-fielded for the successor missions - I think it goes under the name LVS now. One reference appears to be here: https://www-robotics.jpl.nasa.gov/what-we-do/applications/la...
ALHAT/LVS problem seems to be the overly broad requirements, it's overengineered (hence the modularization in LVS) which led to long delays during the development. For comparison, Chang'e 3 TRN solution was dead simple, it was roughly speaking a webcam combined with the specific lighting angle during the landing. Then they iterated on it in subsequent missions, creating a decent system that was less dumb and restrictive than the original.
Interesting that its mostly image/ video processing, which isn't a 'traditional' guidance/control approach.
> the lunar landing of the probe using image processing to guide the final approach
Anyone building precision weapons has gotten fairly good at this.
Weapons guidance systems get to be simpler in many ways.
If you've seen some of the Lunar or Martian landing videos, you'll notice that it's very hard to tell the scale. Especially on the Moon, the lack of atmosphere to disturb the surface makes it fractal-like, which probably really messes with the CV algorithm. It'd work fine when high up, but as you approach for landing, it would probably struggle, especially for, say, estimating how far away the surface is.
Don't they use radar altimeters to get altitude? You don't need to rely only on image processing. You can even pull off stereo using a single camera since you are moving and know the altitude at every point.
They definitely combine several sensors to get a proper height reading, but as we've seen with the American and Japanese landers, getting good readings from the sensors, properly accounting for all factors that might affect sensor readings and being able to properly handle sensor disagreements is quite challenging.
LIDAR/RADAR performance weren't issues with last two attempts. SLIM had a thruster kaboom, IM-1 had human eye safety mechanism wired incorrectly.
This one seem to use scaled down Soyuz capsule as reentry vehicle. They must have reused a lot of proven hardware and software unlike those.
Better call my man... Kalman.
https://en.wikipedia.org/wiki/Kalman_filter
For distance during landing I would be thinking a spatially maximally distributed array of quartz-shielded, thermally-supported laser TOF sensors along nominal extremities, but that's just because they're familiar to me, small, power-efficient, highly linear, relatively accurate, and cheap. Unsure if the IC physics assumptions work in non-atmospheric conditions. Perhaps the output can be re-scaled to obtain cheap and accurate enough readings.
A non-dilettante with an actual physics degree would clearly be desirable ;)
A kalman filter wouldn't account for say, the issue that hit the HAKUTO-R lander, where because the reading on the radar altimeter changed too rapidly, the computer assumed it was faulty, or the IM-1 lander, where they initially had a lot of trouble with altitude sensing (in part because they forgot to remove the covers from the laser rangefinders), managed to work around it, and then failed to fully sense and cancel out the lateral velocity, causing it to skid along the surface, snap a leg and tip over.
The first sounds like bad assumption (hard fault limit).
The second sounds like bad process leading to bad input, at which point it becomes garbage in, garbage out. The workaround was untested and insufficient.
While you are of course correct the filter will not fix these, none of these are the fault of the filter, they are all human process issues that are firmly out of scope.
The apollo guidance system was one of the first production deployments of Kalman filters. Here's the source code: https://github.com/chrislgarry/Apollo-11/blob/master/Luminar... (it was used for star navigation, not sure about the lander).
The problem with RADAR on the moon is there's an unknown amount of dust between you and the reflective surface.
Apparently cameras also have issues because the lack of atmosphere means everything is high contrast.
So basically, you don't actually know your altitude, and your visual systems may not be reliable.
It is a lot more difficult in space, since you don't have the atmosphere to steer for free and because fuel margins get very expensive. Being familiar with these image processing systems, I could see it being a significant challenge.
They only linked to other articles of the guardians but not to the official announcement.
Official announcement by the CNSA: https://www.cnsa.gov.cn/n6758823/n6758838/c10565180/content....
Congratulations for such an achievement!
Super impressive. A return mission from the far side is very technically difficult, and pulling it off paves the way for a staffed lunar lander on the far side.
How is it more difficult than return from the near side, besides the need for a relay?
Having to route all of your communications through a relay, having to explicitly build out backups to your backups for comms rather than being able to look up with your instruments, a longer delay requiring more autonomy on the lunar surface, more radiation, more micrometeorite impacts, rougher terrain, other things.
I sincerely hope there's no moonseed in it.
What are they expecting to be different about samples from the moon's far side to those previously collected?
The reason you seek to explore what you don't know is because you don't know what you don't know.
In general I don't think people really appreciate how ridiculously little we know about everything outside of our planet. Like for instance it was only in 2013 (!!!) that it was discovered that Mars' soil is relatively 'moist', about 2% water by mass. And that's just the topsoil layer - it's suggestive that below the surface it could well be even more moist.
But the Moon's much closer, so we must know more, right? Well water ice on the Moon was only confirmed in 2018!! [1] So actually starting to get surface samples, and explore more of the Moon, ideally with a rapid return to humans on it is so exciting because who knows what we'll find out next? The unknown is precisely what makes exploring the unknown so enticing, rewarding, and fun!
[1] - https://www.space.com/41554-water-ice-moon-surface-confirmed...
> Well water ice on the Moon was only confirmed in 2018
Thats for surface water, we confirmed a while longer the moon has water underground.
> The reason you seek to explore what you don't know is because you don't know what you don't know.
In theory yes, in practice it's never the case, you have to justify hard why you want to do the experience and what you expect. Especially with multi million dollar experiences like these
No idea what they’re expecting, but I would expect some interesting differences based on our current understanding of the geological differences between the two sides. Apparently the near side was warmed by Earth early in the Moon’s history which meant the far side cooled more quickly and developed a thicker crust.
Leaving aside all the geopolitics and bragging rights, I would imagine that one scientifc reason for trying is that since the far side gets more meteor hits, there may be more material from elsewhere in the solar system. (Having said that I know nothing about this mission and am just guessing.)
I mentioned Gold on my comment before I read yours. Yes that makes perfect sense. Why ruin your reputation (hehe) with children mining rare metals, when you can have known and unknown rare metals flown in..
It is costly though to bring in a ton of <insert element> from the moon.
In the book Super Volcanoes, I read about how complex the moon is geologically and how little of it we've examined and how poor our understanding of the geological history is. Apparently we can't yet explain how it was geologically active so recently. Imagine if the only rock samples we had from Earth were from a couple random spots on the surface, from wildly different time periods, and trying to develop together a theory of how its geology changed over time from that.
Checkout this paper:
https://www.sciencedirect.com/science/article/pii/S254243512...
Takeaway: The samples indeed are very different.
They hope to test their hypothesis that volcanoes on that side became inactive 4 billion years ago. Great question frankly, this article goes into it in much more detail (I just selected a likely looking blurb, there are other elements of the theory)
https://www.cnsa.gov.cn/english/n6465652/n6465653/c10523137/...
I was thinking about "what have they found there?". I remember reading that the Central Bank of China was feversly buying Gold, and a few weeks ago they stopped all buying. Then this came to focus, and it made me think... did they find 100 tons of Gold up there, and they know that if they start bringing this in (on Earth) they price will plummet, and expect a massive sell-off in the next few weeks???
But then I do read and watch too much sci-fi!!
I think it is very expensive way to acquire 100t of gold. It is cheaper to just buy or mine them from our planet.
In that case, this destination should be Venus, 'cos it's Chinese name is Gold Planet, if translated back to English literally.
No, absolutely not. I can't say future space mining isn't a consideration (a moonshot if you will) but the challenges are astronomical. First you have to setup a mining and refining operation in an incredibly hostile environment and then you need to ship it back. We just aren't there yet.
you won't expect rock samples from New England and middle east are the same, right? The current theory is that samples collected by Chang'e 6 could be the oldest sample we ever saw from Moon. It would be worth to study and prove that.
I wonder if not being shielded by the Earth's magnetic field during full day would lead to a different balance of isotopes deposited by the solar wind.
I just learned it on the radio on my way to work this morning.
The last sample reveals something about the surface of the moon.
The sample this time is from a big, deep hole created by a heavy hit which penetrated into the core of the moon, thus reveals the internals of the moon.
It would be a good sci-fi plot to find a moon base hiding back there. Populated by aliens/your current enemy/tech billionaire mad scientist/high IQ octopi
It could also be an abandoned base.
Already exists, but it's Nazis.
The plot would be every similar to Apple TV's "For All Mankind" show, I won't spoil who all populates the moon though.
Or your ancestors
> What are they expecting to be different about samples from the moon's far side to those previously collected?
Different bragging rights.
Do either China or the US have plans to attempt a Mars sample return? Does China have the rocket power to attempt such a mission? The US seems focused solely on the return moon missions, with any Mars mission presumably behind at least 5 more major Artemis missions that are scheduled through 2031.
Tianwen-3 is the Mars sample return mission of China, which is 2030 on the current plan. They do have the rocket to support the mission. https://en.wikipedia.org/wiki/Tianwen-3
China as far I'm aware doesn't have any solid plans on the books yet. NASA has been working on planning out a Mars sample return for a few years now, part of the Perseverance rover's job is to collect samples, store them in canisters, and drop them for future retrieval. This ensures that the samples have a much lower risk of having been contaminated, if, say, they end up being retrieved by a crewed mission.
The issue has been that previous proposals have all been too complex and too expensive, eg, a second rover that has to retrieve the samples and then place them on a lander which has a rocket on-board, the rocket then launches back into orbit, where an orbiter picks up it up and brings it home.
They've recently started soliciting other ideas for a way it might be done from private industry. The most promising in my opinion being to use a Starship, so they would be able to send a large enough return rocket to not need an orbital rendezvous, significantly simplifying things. I doubt they're seriously proposing a crewed Starship sample retrieval just yet. Another neat proposal I've heard is to build on the success of the Ingenuity helicopter to have a bunch of similar helicopters go around picking up the samples instead of a rover.
It is such a classic issue with space travel. One way trip is relatively easy, return trips are WAY more difficult because of the reasons listed.
China has a plan to get an orbiting probe to Neptune but nothing about returning Mars samples. Highlights the different scale of the problem.
Excellent info, thank you. If you or anyone else have favorite news sources for keeping up on space programs, please share. I tend to get most of my space news from HN.
I usually just pick it up from X, following a couple of good, space focused journalists helps push most space news up to me.
Adding to the Mars Sample Return thing, apparently China just recently announced their intention to do it ~2030.
It was just in the news recently, a NASA request for proposals:
https://www.nasa.gov/news-release/nasa-exploring-alternative... ("NASA Exploring Alternative Mars Sample Return Methods")
The latest Mars rover has an (IMHO, purely performative) function for collecting samples that, in theory, could be retrieved for Earth return by a separate lander in the future—one that hasn't been budgeted or designed yet.
https://en.wikipedia.org/wiki/Perseverance_(rover)#Samples_c...
Yep, the latest NASA lander is dropping samples in containers meant to be picked up by a later mission: https://www.nasa.gov/news-release/nasa-sets-path-to-return-m...
There's also a sample container inside the rover intended to be sent back. The cached samples exist so that more can be taken, and so it's still possible to get samples if the sample container in the rover fails to open for some reason.
The initial plan for retrieval involved Roscosmos and ESA, but that's been called off for now. So they need some new plans. My favourite part of their initial sample return plan was the decision to not use a parachute to land it on earth, since they couldn't be sure one wouldn't fail.
SpaceX
That's right, I forget SpaceX is ultimately focused on Mars missions. I mostly hear about them now in relation to their role in the upcoming Moon missions.
Now let's see China accomplish the same with all-analog circuitry
And nazi scientists
The international moon base plan is fascinating.
https://en.wikipedia.org/wiki/International_Lunar_Research_S...
(nuclear power plans by Russia not so much)
Is there enough gravity on the moon to prevent the long-term health problems from the space station like bone, muscle and vision loss?
> Is there enough gravity on the moon to prevent the long-term health problems from the space station like bone, muscle and vision loss?
Nobody knows. You might think scientist can science up answers to any question but it is impossible to know this without long term data which is simply not available.
There were some experiments done in parabolic flights [2] but those only last for a very short time.
There is this literature review [2]. They are not optimistic: "It can be anticipated that partial gravity environments as present on the Moon or on Mars are not sufficient to preserve all physiological systems to a 1 g standard if not addressed through adequate countermeasures." Which is space speak for "you will need to go to the gym on the moon". But they are willing to admit how little there is to know for certain: "The methodological quality of the vast majority of the available/included studies is too low to generate a compeling evidence."
1: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10411353/
2: https://www.frontiersin.org/journals/physiology/articles/10....
> it is impossible to know this without long term data which is simply not available
Generating these data is one of the biggest pay-offs of a lunar colony.
I know data is the plural of datum but seeing "these data" instead of "the data" is always so jarring to me. Almost as jarring as seeming anyone use the word "datum" ever.
Is this one of those generational things like "on accident" vs. "by accident" or regional things like "math" vs. "maths"?
> The word data can be either singular or plural depending on meaning and context. In general usage, data is treated as singular when used as a mass noun to mean “information” and as plural when used to mean “individual facts.” In scientific and academic writing, data is almost always used as a plural noun. In digital technology, data is usually treated as a singular mass noun to mean “digitally stored information.”
While it’s used interchangeably a lot, it’s also based on whether you have a scientific or CS background. My hunch is that the scientific plural usage will eventually largely die out except in very specific situations after a few generations given that software is eating the world.
[1] https://www.thesaurus.com/e/grammar/data-is-or-data-are/
Huh, didn’t know about that line. I do tend to refer to scientific data plurally, where each datum is meaningless, and technical data singularly.
> Is this one of those generational things like "on accident" vs. "by accident"
"On accident": Abomination! Kill it with fire, now! </OldFartRant>
Another, perhaps even more interesting question, is also how the first generation who are born in low g will evolve and adapt. And this, so far as I know, is a completely unexplored question. Mammal experiments might be interesting, but at some point you simply have to do it with humans, not only because of our fairly long gestation period, but also because of how absurdly undeveloped we are even once when born. There's every reason to think a human baby may develop differently than other mammals which do far more development within the womb.
> And this, so far as I know, is a completely unexplored question.
To date, no mammals have given birth in space. We sent pregnant mice and had them return to Earth to give birth, and we've sent mouse zygotes and grown them in space, but no birth!
Mice in space:
That video is awesome. This [1] seems to be a pertinent paper. One thing I don't understand is why we intentionally limit the experiments. Having male + female and then running the experiment through generations seems like it would be vastly more informative. For instance that 'race tracking' behavior around the cage, only seemed to emerge in young mice. What sort of new behaviors, adaptions, etc will emerge in the first generation born entirely in low g?
Or perhaps even the 2nd generation could be even more telling. Why not simply run the experiment until they all die off, or go full Malthus? Another interesting idea would be to create a faux terrarium type enclosure instead of a plain cage. Would the mice exhibit a bias towards the "ground"? And also it's kind of odd that none of the studies thought to include a lens wiper for their cameras after the first one demonstrated the problem. In 0g, various 'matter' ends up getting stuck on the camera lens, increasingly trending towards 0 visibility.
> nuclear power plans by Russia not so much
Why? Any lunar base without nuclear power plans is not a serious effort.
The moon is fairly unique (relative to Earth) in that the exact same spot will go from -200C to +100C on a two week cycle (day and night). It seems "obvious" that there must be some clever way to exploit this to generate energy in a simple and novel fashion.
> seems "obvious" that there must be some clever way to exploit this to generate energy in a simple and novel fashion
Sure, once you have two-week power-storage infrastructure. (And the scale to harvest a useful amount of energy once a month on average.) In the meantime, i.e. our lifetimes, you have countries that can build space nuclear reactors and countries being performative.
I see a couple of issues here. The first is that creating, maintaining, and operating a nuclear facility on the Moon would almost certainly be far more challenging than "just" maintaining a couple of weeks of power storage. But that kind of implicitly leads into the other issue. That is that you only really need the scale of power that nuclear can offer once you've already substantially industrialized the Moon. For some simple habs and research areas, even something as small/simple as a radioisotype generator [1] would be more than fine.
Beyond all this, I meant novel when I said novel. The regular extremes of heat and cold offer all sorts of interesting ideas. You've got room for predictable and endless convection on basically an arbitrarily large scale there. There is certainly going to be some clever way to exploit this in a novel fashion.
[1] - https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...
I have always assumed that the first moon colony would be on the north or south pole to avoid this issue. Not too hard to imagine a solar array set up to track the sun with a very slow rotation. The colony itself would be in a crater to avoid direct sunlight and provide a place to dump the heat from the solar array.
Otherwise the need to bring enormous power storage to handle the half month of darkness and bitter cold makes solar a bit impractical and the only other reasonable alternative is nuclear power.
The big problem with attempting to exploit the temperature differential is that it happens on such a slow cycle that the total amount of energy available is quite low.
Could you exploit the temperature differentials between the either hot or cold surface, and the presumably in-between temperature at the bottom of a drill hole?
In theory the temperature underground should be the average of the surface temperature, so you could use that gradient to generate energy at night. Someone smarter than me would have to do the math on the energy density of a scheme like this, my gut says it's going to be fairly low and you will need a really big power plant to supply even a modest colony.
Good news! Thermal cycles are caused by the sun, and we can harvest sunlight directly! Storage is an issue...
Storage is not an issue. It's been solved for decades. In fact, energy storage is amazing and cheap now, thanks to smartphones and EVs. You can buy consumer level batteries for very very cheap.
Battery tech is awesome, but I think you're overselling it a bit. We've barely started figuring out grid-scale battery storage on Earth. There's 2 big reasons the Moon is going to be much much harder:
1. Batteries are heavy, and space ain't cheap. Current launch pricing is about $1.5k/kg to LEO. The Moon will be more, it's further away. Even if Starship brings that down by a factor of 10, transportations costs are still going to be astronomical.
2. The day-night cycle on the Moon is slow. Your batteries are going to need to be able to store half a month worth of power. You'll need 15x more batteries on the Moon than you would on Earth.
I often wondered, how do you deal with all the waste heat from a fission power reactor, in a vacuum?
Giant radiators?
edit: fixed typo, derp. fusion=fission
> Giant radiators?
Yup, that's the thing on top [1].
Thanks, I have seen a lot of pages on nasa.gov, but not that one. Neato!
On the Moon you could also use the Moon itself as a heat sink. But yeah, any near-term solutions would use giant radiators.
Solids don't conduct too much heat. I think most of the cooling in a nuclear plant is generated by evaporation of water.
Yes, what I mean is that theoretically you could do something like have a very very wide base to passively dump heat into the ground (since we're still only looking at kW scale reactors in space), or actively cycle large amounts of regolith through the cooling loop (say, via a heat exchanger from a closed water loop) and dump it out. Depending on how much heat the system can handle, you could maybe even extract stuff boiling off from the regolith.
The nuclear plant nearest to me uses sea water, which is put back into the ocean.
Interesting. I had to look for more details. I found this link https://nuclear.duke-energy.com/2013/11/13/why-don-t-all-nuc...
Oversimplifiying: All new plnats have cooling towers, so the water they return to the environment is not too hot.
Perhaps? Any reason that sounds silly to you?
No, and this is not some attack on nuclear power. I am just curious. On earth, nuclear power plants use lots of water and cooling towers. How does that work in a place with no spare water?
I also meant to write fission in my original question, not fusion.
Mostly cooling towers are not likely to work in a place with no atmosphere.
Radiators though, are constantly used in spacecraft, and seem to work well. Low gravity, no motion might let the thing be mostly the radiator, with not much support structure. Except it might need to be in shade, in the shadow of a building? hill? solar panels?
> How does that work in a place with no spare water?
I wonder if recycling human liquid waste through evaporation could be of some use for that purpose.
maybe not so hot indeed due to the scarce air that's why it's so cold at night on the moon. Only turn on the reactor at night to generation and use capacitors at day?
You can't really turn fission reactors on and off, they're always producing decay heat even if not being used for power generation. But why not radiate the excess heat into the crust of the moon with a subsurface loop, kind of like a ground source heat pump.
The day is 28 times longer than on Earth. You'd need very big capacitors.
It would likely be a thermal reactor, I guess? So no waste heat, since the little heat it gives is used to generate electricity.
Most nuclear reactors are thermal power plants and they all need to dump waste heat. Thermal power plants convert heat into electricity with turbines and are limited by dumping the waste heat.
Are you thinking of radioisotope generators? Those aren't reactors. They use thermocouples and need to get rid of the waste heat. The Voyager RTGs have radiator fins.
Yeah, that's what I meant, sorry about the incorrect naming.
Thermal power plants don't use up the heat. They make energy through its transfer (like a dam with water).
Heat is what you use to make steam and drive the turbines with. I don't understand your question.
Solar PV linked to battery storage is the obvious energy source for a moonbase. All reactors require coolant circulation and water is going to be among the most valuable commodities on the moon, not something you want to circulate through a reactor (where you inevitably get tritium formation, making the water unsuitable for other uses).
Maybe you could use helium or liquid sodium metal as the primary coolant, but then you still need to generate electricty via secondary water coolant loop that runs a steam-powered turbine. Really not plausible on the moon.
> Solar PV linked to battery storage is the obvious energy source for a moonbase
It's not serious with chemical propulsion and the Moon's day/night cycle. Put another way, if one team uses nukes and is, as a result, power unconstrained, while the other spends all its energy launching solar panels and batteries to keep life support online, it's obvious who's going to be doing any science.
> All reactors require coolant circulation and water is going to be among the most valuable commodities on the moon
Sodium and sterling, no water [1]. There is a reason even NASA is only seriously considering nuclear power [2].
[1] https://www.nasa.gov/directorates/stmd/tech-demo-missions-pr...
Solar PV battery combo is just a giant spatial transmission line system for a fusion reactor. For high density applications, fission and/or fusion make more sense.
It's just that we're close enough to the Sun, and that a lot of us are living in low-density residences.
Solar ray density reduces to half of what we get on Earth on Mars our closest outer planet, simply from inverse square law. And deep space people always said it goes down so fast a space nuke is a hard requirement for Jupiter and beyond. There might be ways to make it work on Moon, but PV plus battery is just rural inner planets thing, not the way forward or anything. It's just temporary hype technology.
You'll need a massive amount of batteries for solar night. People severely over-estimate battery storage.
Even on earth, giant grid-scale storage system are not able to supply all the power for region they serve alone for more than some 4 or 6 hours. In the moon, they would have to supply power for some two weeks.
Battery storage is not a real solution on earth, it is even less plausible in the moon.
You'll need an insane amount of battery storage, since the moon only rotates once per month and you'll need to power through a long period of no sunlight.
Or just very long power lines and multiple solar stations, it's not like the moon is impossible large. But that would be harder than a singular location using nuclear fuel, it's true.
A belt of solar panels encircling the moon would solve that problem though perhaps a bit ambitious at present.
Or alternatively, for polar bases, very tall panels, which would be able to be in permanent sunlight.
> very tall panels, which would be able to be in permanent sunlight
Or normal panels on the rim of Shackleton [1]. (You'd still want to bootstrap with fission.)
[1] https://en.wikipedia.org/wiki/Shackleton_(crater)#Potential_...
I do not know for a fact, but I wouldn't think there is a single chance in hell that living in an environment with 1/6th of the gravity we've got on earth would not cause long term effects in your health, specially to the bones and muscle.
I assume that any large scale colonization of space will involve deeply modified germline humans: reduced oxygen requirements, greater tolerance to radiation, fewer rigid bones, tolerance to many forms of low gravity, loss of ability to live on the surface of a high G planet. And I guess an increased tolerance to boredom given how long it takes to get anywhere when minimizing energy expenditure.
Probably fine .. as long as you don't come home.
Also changes eye shape over time, causing vision issues, etc.. Longer you're up there the more starts to go wrong. We were built to fight off gravity. I think its worth considering that it may be fundamentally impossible for humans to reproduce/gestate babies/live entire lifetimes/generations in low gravity conditions.
Well there's a world of difference between micro-gravity (where there have been problems with nice) and low gravity like on the moon (where there's been no experiments)
If you did have viable babies in low (not zero) gravity situations though, would you in fact be starting a new species.
It's not clear when a new specie is different from the previous one, but you probably need:
* Like 100.000 years, probably more. (From the split of us from chimps 5.000.000 I counted like 30 species in https://en.wikipedia.org/wiki/Human_evolution , but the number depends a lot on who count them.)
* Isolate the populations so they can't interbreed (first because they can't meet and later becuse the dna is incompatible)
Radiation is going to be a bigger problem, which calls for a deep underground base, which I'm suspecting it coincidentally also enable centrifugal artificial gravity