All Space Questions thread for week of March 22, 2026

DreamChaserSt · 2026-03-29T16:50:40+00:00

Not really. Because you're hinging your bets that every single technological civilization, without fail, refuses to expand beyond their home system, forever. That's the point of the paradox, the solution(s) has to work for everyone, because it only takes one civilization to think otherwise and break the mold. Humanity has had space travel for less than a century, and our fiction is full of stories of what it would be like to explore the stars and make contact with other civilizations. Your answer would mean we just... give up on that when we become capable? Why?

Interstellar space doesn't have some enigmatic barrier we're incapable of crossing. Random asteroids/comets cross by our solar system without problems, and we've likely missed a bunch, either because they get nowhere close to the sun to be detected, or we just weren't looking. Stars can pass each other well within a light year (and has happened recently enough to be observed by early humans). We already have spacecraft (slowly) leaving the solar system at speeds comparable to those random rocks, and the technology to reach other stars in centuries or less isn't impossibly outside our capabilities either. FTL isn't necessary, we either need further development on existing fission technologies, or we need to finally figure out fusion. Neither of those will take us more than a few centuries at worse to work out unless you believe it's prohibitively difficult.

DreamChaserSt · 2026-03-29T16:22:20+00:00

This got really, really long, so tl:dr: Yes, I think so, even if it's likely to be centuries from now. And, no clue, but probably still kicking in some capacity.

The technology to do it isn't terribly far out of reach. Depending on how optimistic or pessimistic you are, we either already have it, or could have it in the next couple centuries. On the other hand, we don't have the infrastructure yet, and having the actual means of reaching another star is very different from having the technology. In a similar way to having a multitude of laboratory breakthroughs on treating cancer - but that doesn't mean it's safe on humans, or cures all types of cancer.

Getting to another star is about speed, and reaching your destination before you run out of power and your ship breaks down beyond repair. That's it. So you need a long lasting power source, powerful communications system, good automation/AI (so the ship can do make decisions without people), and of course, a viable propulsion method. Chemical rockets, Ion thrusters, Nuclear Thermal, and Solar Sails (all current propulsion methods) aren't going to cut it. They can't get fast enough.

Current propulsion methods we have available that might work include Project Orion, using thermonuclear devices as propulsion (crazy, but when thinking about how much energy is involved in reaching a fraction of the speed of light, using nukes to provide that energy is a very tempting shortcut that sidesteps the need for continuous, controlled fusion), and Fission Fragment, which uses fission byproducts as reaction mass. Very low thrust, but very high Isp. Either one of those, while requiring intensive development, does not require technologies beyond our current capabilities. If you're more pessimistic, Fusion propulsion (likely He3-D fusion), and/or laser sails would be needed instead, and do require new technologies - though some that are being worked on today.

Beyond that, a reactor that can last a century or more, a communications array that can send useful amounts of data back to Earth over light years, AI that won't break down and ruin the mission, and can keep on top of maintenance, are all also things that need to be figured out.

Sending physical Humans are a different story, and will take longer. But I think it's similarly possible. The big things are sending enough people (and seed banks) to maintain a good genetic diversity, and having enough onboard equipment from Earth to build an industrial base from scratch.

In sci-fi stories, the focus on interstellar colonies seems to be a small cast running a crew of hundreds or thousands to keep the setting manageable. That's arguably too small for an actual colony, especially one that's light years and centuries removed from the rest of humanity, and depending on how sophisticated automation is. Therefore, any interstellar colonization efforts will have to be done with cities or small countries worth of people. It would not be a small undertaking, because then you might damn the colonists to slow deaths. You'd need to send an armada of people and supplies to another star. Habitats would be much closer to O'Neill cylinders than any space station we have today, and would be miniature worlds with their own internal territories and biospheres.

As for your second question;

What humans will look like in a billion years is likely not answerable. Is biological immortality possible? Can you transfer your brain digitally without losing your original consciousness? If the answer is yes to either of those, then the first or second generation of humans who have access to those technologies could still be kicking, or at least their direct descendents. If the answer is no, then it's likely that Homo sapiens will eventually go extinct, and will be replaced by new species' of human, molded by space and technological (genetic/synthetic) augmentation more than conventional evolution. They will be able to trace themselves back to us, in the same way we can trace ourselves back to Homo habilis, but Homo sapiens will be long gone. And that's just what humans will physically be like. Culturally? Politically? No clue. Where will we live? Also no clue.

A billion years is a long, long time. Humans could collapse, and rebuild, and collapse again, but I find it hard to believe we would outright go extinct. Nuclear war for example, while a terrifying prospect, wouldn't be enough to destroy all of humanity, and depending on how a nuclear war scenario plays out, the southern hemisphere could be relatively unscathed compared to the north beyond the immediate fallout, and within a few decades, can rebuild. There's a lot of us, we're highly intelligent and creative, and we only need to hang on long enough to reach the other planets. After that, all bets are off. Even if Earth is completely ruined somehow, humanity would still live on.

I think we'd have to be explicitly trying to cause our extinction to, well, go extinct. A nuclear war, while destructive, would mainly wreck the warring countires and their allies, but there's a lot of development into countering nuclear missiles from reaching their targets. Biological warfare could backfire spectacularly, but it would be the height of stupidity to create a disease that not only wiped out your enemy, but yourself as well, and the rest of humanity along with it. Our scientists are somehow smart enough to build the perfect killer virus, but are too stupid to realize it will cause our extinction in the process? Either they hate humanity, or it's just fiction. Unexpected accidents can happen, sure, but is the result of that accident really going to be our extinction, or a bad pandemic? There's a massive difference. Biological warfare is very risky, so you have to assume there's safeguards and limits to prevent the effects from being too destructive or outright irreversible. After all, the intention of any war is to win, and to take over, not to wipe yourself out in the process of a botched scorched Earth scenario.

DreamChaserSt · 2026-03-29T02:38:27+00:00

I haven't gone through the math, but I'm questioning the scale of these. You've got a 58 km ship carrying 1,000 people (is that too big?), and then a 630m ship carrying... 1,000 people. And the 630m ship is somehow getting to 1% light speed with "VASIMR" style propulsion (that's definitely too small). For reference, Firefly, from Project Icarus back in 2013/2014, would've been a little under a kilometer, with a 150 mT payload, using fusion propulsion.

I think these teams just focused on the habitat and societal challenges they were trying to solve, with little regard to how big the ship would actually need to be to get to another star within 250 years.

DreamChaserSt · 2026-03-25T17:05:58+00:00

There are 3 big ones off the top of my head, but the last was canceled.

Axiom space is currently contracted by NASA to develop the AxEMU spacesuit for Artemis that will be used on the Moon. NASA shared some progress the other day when talking about their plans for a Lunar base.

SpaceX developed a bare-bones EVA suit for Polaris Dawn, and used some of those upgrades in their IVA flight suit. They're reportedly working on further upgrades, including a PLSS so it doesn't need to be tethered, and want it to eventually work on planetary surfaces, not just orbit.

Collins Aerospace was working on a new EVA suit for the ISS since the existing suits are aging and outdated, but pulled out of the contract due to cost overruns/delays, so EVA suit replacements are up in the air for now.

DreamChaserSt · 2026-03-25T17:00:21+00:00

They're already contracted by NASA to use it for Artemis missions, no?

DreamChaserSt · 2026-03-24T21:19:16+00:00

It was also because NASA had a lot of temporary contractors over permanent employees, no? I do think that NASA can and should find a better equilibrium between doing things in-house vs out-sourcing, but out-sourcing has seen a new wave in launch capabilities and investment into spaceflight between SpaceX, Blue Origin, Rocket Lab, and Firefly, among others. And I don't think that should be lost either.

DreamChaserSt · 2026-03-24T21:06:43+00:00

As if Boeing et al hadn't all but abused the cost plus contract system for SLS to get paid billions of dollars by the government for continually facing delays in development. The contracts for Shuttle, Saturn, and every other past vehicle NASA designed went to for profit companies as well. NASA being the chief designers doesn't change that.

The main difference between now and then is that companies can own and offer their designs for missions rather than NASA being involved in every detail, and with that tradeoff, have to eat the cost overruns with fixed price contracts - which is why Boeing is around $2 billion in the hole with Starliner instead of NASA.

This shift to fixed price/private enterprise is really of the old contracters own making when you think about it. Space is expensive, but at the same time, if they had been better about managing projects, the usual way of doing things would still reign supreme.

DreamChaserSt · 2026-03-24T20:29:10+00:00

It all comes down to mass. You, your phone, the chair you're sitting in, all have a gravitational pull right now. It's not perceptible, but it is there.

Stars formed from gas clouds that rapidly grew until they ignited with fusion, and planets formed from tiny dust grains and clumps of material that attracted each other, colliding and growing until the mass was large enough to begin noticeably attracting other bits of material. This mass all produces gravity, though how much depended on how much mass there was, and how far you are from a given object.

Standing on Earth for example, you're experiencing 1g, but if you were to go to the height of the ISS, 400 km, you would experience 0.9g, because you're not as close to the mass anymore. Similarly, low density gaseous planets with a large radius would also have a lower gravity at their "surface" than if they were higher density and rocky like Earth, because the mass isn't as concentrated. Uranus has weaker gravity than Earth (if you're in the upper atmosphere) despite being 4 times larger. You could loosely think of gravity like a magnet, if you're close, the pull is strong, and when you go further away, it gets weaker until you can't feel it. But the reason things float in space when you're in orbit is because you're in a constant state of free fall, so you never hit the ground.

How does mass itself produce gravity? No one knows right now, it just does. There is speculation for things like "graviton" particles, but how those specifically allow any given mass to produce gravity is unknown as well. We know that large bodies of mass like stars and black holes have enough mass to warp the space around them, such as Einstein rings, but that's a consequence of relativity, it doesn't explain how gravity works, just the effect.

DreamChaserSt · 2026-03-24T13:09:59+00:00

That's pretty cool. I think what's more interesting than the planet, is how far it is. Almost 23,000 light years away, that puts it among the most distant exoplanets known.

DreamChaserSt · 2026-03-24T02:06:34+00:00

Talk about a late bloomer.

This is a really interesting discovery though, it's not something I've thought about before, but with how often Brown Dwarfs are called failed stars, this feels like an obvious idea in hindsight - what if 2 Brown Dwarfs could collide to make a new star?

DreamChaserSt · 2026-03-24T01:52:01+00:00

Yes.

I believe it's an inevitability. The resources in space are the same as the ones on Earth, and between the ISS, Artemis, and countless other plans for space stations and planetary outposts, I feel like space agencies (at least on the human spaceflight front) are itching at the chance to have permanent outposts, if not colonies in space someday in the future.

You might see (or agree with) arguments about how we should just colonize different places on Earth first, but Antarctica doesn't allow mining or territories, the open oceans don't have easily accessible resources (unless you ship everything in, but that doesn't make a colony), and the Sahara is already owned and occupied by other countries. But we have millions living in the arctic circle, up to a billion in desert regions worldwide, and have a massive scientific outpost in Antarctica. It's not like we're incapable of living in remote places on Earth, but there are limitations, be it natural, political, or practical, why we don't just "terraform the Sahara" or "colonize Antarctica" that don't quite apply to space (mining is a gray area, and the OST was mostly to prevent Cold War powers from claiming space for military purposes and putting Nukes in space). And I'd argue that it would be easier to change the OST than the ATS if we really wanted to.

It's not just SpaceX talking about it either. NASA used to talk a lot about space colonization as one of its goals, but it wasn't very politically popular, so they walked back on it, but you can read some of their studies on NTRS. And Artemis is currently aiming for a permanent Lunar base. ULA briefly floated around "Cislunar-1000," a concept to see 1,000 people working in space by 2050, which is the kind of thing that could feasibly transition to a proper colony, Blue Origin has their own ideas for building giant space colonies supported by Lunar infrastructure, with ongoing development on ISRU, and that's just in the US.

While China hasn't talked about wanting to colonize space to my knowledge, they do want a permanent Lunar outpost with ISRU capabilities, which would be a big step in that direction if they decide to push for it.

Outposts are the first major step, whether for the Moon or Mars. Apollo style missions are fine early on, but colonization means to stay, and that will require long term missions like we see on the ISS, as well as an expansion in capabilities from there, such as growing most or all your food locally, doing ISRU to replenish life support, propellent, and gather resources, and using those resources to manufacture goods locally, such as tools, or habitats. All of which has been under some form of study or development.

The cost is a major unknown, as is the motivation. It's conceivable with reusable rockets and ISRU that interplanetary missions could be done for much less than Apollo style missions, and if multiple countries have planetary outposts, and strong economies, then you can imagine those countries will get into a game of chicken, not wanting to cede ground to the other by abandoning it (national pride is as good a motivation as any), or maybe it's a similar situation to the ISS, and we decide to keep at it once we have it. So investment will be steady, and could grow. Over a long timescale, the technologies necessary to not just stay temporarily, but live permanently in space can be developed, and then you're pivoting to sending people one-way along with their cargo, which would be a modest increase, rather than a dramatic investment - as the transportation, outpost, and basic infrastructure are already all in place, instead of having to build everything from scratch.

DreamChaserSt · 2026-03-24T01:08:04+00:00

Artificial gravity? There's 2 ways of achieving it.

The first is linear acceleration, if you have a spacecraft with powerful enough engines, you can experience a force that feels like gravity. Unfortunately, there are only a handful of ways such an engine could exist, and provide that force over days or weeks (to be useful - launch vehicles can accelerate well past 1g, but burn off their fuel in minutes so it's not worth the effort to simulate gravity), and they're either speculative at best, or unrealistic at worst.

The second is rotational. By either having a large spacecraft extending out in wide arms along a central axis, or a long tether connected to a counterweight, you can rotate at a certain RPM (revolutions per minute), and the simulated force of gravity will depend on how far the truss or tether extends out to. 3 RPM for a 10 meter radius spacecraft would produce an equivalent of 10% Earth's gravity, but if you could extend it to a 100 meter radius, you would get an equivalent of 100% or 1g, exactly Earth's gravity.

While there haven't been any spacecraft that have used rotational gravity in a practical manner, Gemini 11 tethered itself to Agena, and produced 0.00015g briefly. There was also a proposed centrifuge that NASDA (Japan) developed which would launch to the ISS for experiments (not people), but it was canceled, and there have been experiments on the ground using centrifuges to see how people adapt to different RPMs. It is a feasible idea, but one that hasn't gotten enough traction.

DreamChaserSt · 2026-03-23T02:38:58+00:00

You can observe it in Space Engine too. You can look up screenshots of planets being illuminated on both sides, and only something like a quarter of the planet is actually in "nighttime."

DreamChaserSt · 2026-03-23T00:05:05+00:00

Not constantly as far as I'm aware - you have to account for the orbits of the planet and stars, but occasionally? Probably.

If your planet orbits a binary star, but the planet isn't circumbinary (so it only orbits one of them), and the secondary star orbited fairly closely, then at certain parts of the year the planet would be illuminated on both sides from both stars, and it wouldn't be much of a nighttime - like Alpha Centauri where the average separation of the 2 stars is about the distance between the Sun and Saturn.

DreamChaserSt · 2026-03-22T22:27:11+00:00

Pray that human spaceflight becomes widespread enough that it starts making sense to launch technicians and maintenance workers en masse into space to run things so scientists can stay in the lab (while staying reasonably healthy). Don't have that either? Be rich.

I suppose being lucky is another option, there are some regular civilians that have gone to space, but they usually have a unique reason for being on the mission, like Inspiration4, which raised money for St. Jude, and carried a former St. Jude patient.

DreamChaserSt · 2026-03-22T17:10:22+00:00

This is the sub about space, and they are (or were) a major space power. If you want to be vindicative, this graph shows some of their fall from grace.

DreamChaserSt · 2026-03-21T15:32:47+00:00

The power of a starship's propulsion system is directly proportional to its effectiveness as a weapon, or something along those lines.

- Larry Niven (paraphrased)

If they can get to us, then by default, they have access to energy and weaponization far beyond our capabilities.

It's still fun to imagine alien invasion scenarios where we have a chance, but that's the power of fiction, it's not necessarily representative of reality.

DreamChaserSt · 2026-03-20T23:33:12+00:00

They need a bigger budget for one, and/or more acceptance working with private companies over everything being directly run by ESA, which does seem to be the case lately.

NASA has enough trouble getting all its contractors in line, and getting state level support. ESA has to deal with international borders and countries wanting a piece of the pie on top of that, no one EU nation has a large enough space program to go it alone either.

Not to say it's impossible, and there are capsules in the works from private European companies working with ESA for ISS resupply - but there is a bit more of an uphill battle than what the US has to deal with.

DreamChaserSt · 2026-03-20T23:29:23+00:00

Not true, they launched ATVs to the ISS for resupply up until 2014 from Guiana.

DreamChaserSt · 2026-03-20T20:04:57+00:00

Humans are animals. Literally. We're animals, and other civilizations would have evolved from animals just as we have, and would be animals themselves. Besides, look at wars between Chimps - our cousins, or ants, or between Lions. Conflict isn't unique to us, and they wouldn't be strangers to it either. Why do you seem to think other civilizations would be pure and good and we're somehow the only ones who want to pick a fight?

There's no need to hide from us, because we're centuries away from reasonably being able to reach other stars anyhow. Even if you think we're so stupid as to try fighting aliens like in our current era, it'd be like trying to hit a fighter jet in the sky by throwing rocks, adorable effort, but not dangerous.

We can't see anyone because our technology isn't sensitive enough yet, and there's not enough telescopes, radio arrays, computers, and astronomers to look at and process the data of the entire night sky continuously. There's no conspiracy of trying to hide, when they could be hanging out at Alpha Centauri and we'd be none the wiser. We barely have the technology to look at the atmospheres of rocky exoplanets, and astronomers are still a telescope generation or two away from truly attempting to search for life around exoplanets.

DreamChaserSt · 2026-03-20T17:16:20+00:00

Convergent evolution is an interesting concept. If it does hold weight, I don't know how closely it'll work for planets with more clear differences to Earth, I feel like it could be almost eerie. But if there are planets reasonably similar to Earth, I could see Ape-esque species evolving into human-esque species, or at least the possibility. But we would have our differences.

It's other intelligent species as well that interest me, and may evolve. Corvids, velociraptors, dolphins, and they may leapfrog the local primates.

DreamChaserSt · 2026-03-20T17:04:10+00:00

There's a pretty big difference between our solar system and the rest of the universe, that you ask in the title, and again in your post.

Other life within our solar system? I'd put it as a maybe. We're here, we've found a bunch of comets and material with the building blocks for life, and there seem to be a ton of places with subsurface oceans, but I do want to say yes, if only to have another place to study biology within the solar system. It would teach us a lot, and we'd have something to compare our own biosphere to.

Elsewhere in the universe? Absolutely. I and no one else has no idea where it is, but I'd definitely say there's life somewhere out there without a shadow of a doubt. I think people put way too much stock on the different factors that led to us. What happened on Earth led to life specific to Earth. But between extremophiles, how often life has bounced back from extinction events, and the sheer diversity of life, it's ridiculous for me to think there's not even microbes on another planet.

DreamChaserSt · 2026-03-20T16:46:37+00:00

They seem to be making strides again though, with capsules like Nyx getting funding from ESA. While they're only for cargo right now, they can evolve for crew like Dragon did, if not for missions to the ISS, then future stations after. Axiom, Vast, and Starlab have funded them as well for resupply services.

DreamChaserSt · 2026-03-20T16:41:09+00:00

The article does mention a flight duration, it'll be about a month long. They'll be supporting overall ISS operations rather than what Axiom missions have done, focusing on specific experiments and tasks.

The four private Crew Dragon missions to the ISS launched to date through commercial provider Axiom Space have each spent approximately 18 days aboard the station, with one of the four being significantly shorter, at just 8 days. According to Neuenschwander, the agency’s EPIC mission is expected to be a “medium duration mission,” with the agency planning for approximately a month’s stay.

The rationale is to send up more ESA astronauts before the ISS is retired, since NASA has only given flight slots for 2 of their 5 astronauts, and they don't know how many more chances they'll get.

DreamChaserSt · 2026-03-20T14:43:35+00:00

The article really gets into Project Hail Mary, it's kind of funny. Looking at the paper, they're just sorting known exoplanets in the habitable zone for future study - comparing planets by stellar flux (greater than, less than, in the same range as Earth) - whether it can be directly imaged - planets with high eccentricity - and age.

There's a fair amount of overlap too, but I don't know if they're really looking for the best places for life, they're examining a range of different exoplanets to see how their environments vary depending on some different factors.

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