Link here https://t.co/3Is5Q8Q1gI. (I shared this yesterday, but forgot that this site spikes such links)
— Pinboard (@Pinboard) February 27, 2026
So. Many. Moving. Parts!…Maciej Cegłowski, aka Pinboard, at his SubStack Mars for the Rest of Us, with “A Primer on Long-Duration Life Support”:
Life support is the biggest technical obstacle to the human exploration of Mars.
This fact makes people mad, because there are all kinds of other obstacles that are fun to solve (orbital refueling, landing heavy payloads, making rocket fuel out of Martian air), and life support has a fun factor of zero. It is a thankless world of dodgy sensors, failing bearings, and bacteria trying to grow on absolutely everything.
But if we want to get to Mars alive, we need for this stuff to work.
Requirements
An astronaut in space needs 840 grams of oxygen, 2.8 kilos of water, and 1.8 kilos of dried food a day to stay alive. They also appreciate the little touches, like water to wash with (0.7 kg), fresh clothes (1.5 kg per week), wet wipes (0.2 kg/day) and a toilet (1.4 kg for canisters and wipes).On the output side, each astronaut exhales around a kilo of carbon dioxide and pees out a liter and a half of urine. They also produce a fairly small quantity of feces and menses (though many women opt to medically induce amenorrhea during space flight)…
On shorter missions like Apollo (~12 days) or Shuttle flights (~14 days) it makes sense to pack everything a crew needs with no attempts at recycling. In this paradigm, carbon dioxide can be scrubbed from the cabin air with disposable lithium hydroxide cartridges; everything else is carried along in the space version of a picnic basket.
On longer missions, trying to carry single-use supplies gets unwieldy. A crew of four on a 1,000 day mission to Mars would need 48 tons of consumables, about equal to the mass of the entire spacecraft. And even if mass were unlimited, there simply wouldn’t be enough room to fit everything on board.
So past a threshold of about 30 days, you have to make some attempt at recycling…
Food
Food may be my favorite technical barrier to Mars travel, because everyone assumes it has been solved, or that it is easy to solve, while the people working on it mop the sweat from their brow during the day and try keep the shaking in their hands from rattling the ice cubes in their whisky glass at night.Astronauts have hated space food ever since the first meat cubes came back uneaten from Project Gemini. Even on the ISS, where fresh foods are often available, getting crews to eat adequately is a struggle. Whether it’s because the stomach senses satiety differently in zero gravity, or because the space station smells like a toilet, crews have historically consumed only 80% of their rations.
On a multiyear mission, such a calorie level would lead to malnutrition and embarrassing deficiency diseases like space scurvy. So we need to come up with ready-to-eat meals that are nutritious, storable for five years without refrigeration, and appetizing enough that a crew can eat them for a thousand days without wanting to murder each other.
These kinds of meals don’t exist. Their closest equivalent is the military meal ready-to-eat (MRE). But as any soldier or prepper will tell you, an MRE is not something you can subsist on. The meals are not nutritionally complete, and soldiers’ own backronym for the combat ration (meals refusing to exit) sheds light on a notorious shortcomings. Defense department guidelines stress that soldiers should not be fed MREs for more than 21 days at a time…
Much more information, and useful charts, at the link. (I am mildly fixated on the fact that astronauts use the same indicator for discarding their disposable undergarments that my teenager brothers used to decide when to change theirs.)
War for Ukraine Day 1,466: A Brief Sunday Night Update
dmsilev
There’s a great book called A City on Mars, published a few years ago, that goes through all of the very very many “gotchas” involved in setting up, well, a city on Mars. Or even just a village. It will no doubt come as a huge shock that Elon Musk’s claims of being able to do so any time soon are just slightly lacking in necessary detail.
Peale
@dmsilev: I thought the hypothesis that they want to test is kind of like the “new Adam and Eve” idea, where we just send a billion people there and eventually one or two will have the genetic make up necessary to survive there.
Jay
@dmsilev:
That’s why he’s (cough, cough) going back to the moon instead, allegedly.
Tesla’s did not become “self driving” in 2014, and 12 years later, the new promise is at the end of 2026.
Sure, Jan.
Redshift
Regarding the laundry question, I got to go to Q&A event with astronauts at NASA HQ a while back, and one of the questions was about that. Part of the answer was that clothes don’t need to be changed for much longer because in zero-g, clothes just float around you instead of resting against your body, so they absorb sweat and stuff much less.
prostratedragon
Ishiyama
Science fiction is still fiction. As are the adventures of Horatio Hornblower, which is what their mental image is of a trip in space. Somebody needs a reality check.
Peale
@Ishiyama: The idea that Mars is habitable is just an idea that will not die. It should have died in the 1960s when we finally sent probes to the planet. But then the question is asked “was it ever habitable and did it have life” so we need to keep searching. Oh, maybe it is habitable but the life is under ground. So we have to start digging. So yeah, science fiction is still fiction. But its what’s been funding Mars research for the past 50 years.
Layer8Problem
@prostratedragon: Um, did I miss something in the X link, the one that I am refusing to hit the Privacy Badger button for so I can view it because X, that brought those two points up? I definitely like “Bye Bye Life” as a probable finale to Musk’s Wicked Cool Long-Term Space Adventure, and that’s one of my favorite Bugs Bunny cartoons.
StringOnAStick
While necessary for moving the stories along, the transporter and food/thing replicator devices in Star Trek are still fiction and remain so, even if Elon sees something else when he’s tripping on Ketamine. Half the human population apparently can’t distinguish between Hollywood plot devices and, you know, reality. Hell, Star Wars worked for Reagan because they mocked up some great animation and Ronnie’s demented brain saw it as real and sold that thing like Boraxo.
Chetan R Murthy
@StringOnAStick: haha, also workable fusion drives, and (somehow) space drives that don’t need reaction mass to shove in the opposite direction from that of travel. And “space elevators”. Soooo many plot devices to make sci-fi work, and people start to think it’s real.
Jay
@Chetan R Murthy:
Well, if you get high enough, the energy required to launch and escape, becomes significantly less.
Not sure if that’s altitude or ketamine.
I am not a rocket scientist.
SpaceUnit
I think it’s possible that one wouldn’t necessarily die on Mars, but it sounds as though a person would almost certainly want to die.
Chetan R Murthy
@Jay: You don’t need to be a rocket scientist. Imagine building the airlift capacity needed to fly a quantity of steel and other materials needed to build a supercarrier, across half the globe. That’s certainly going to be needed to “get high enough” to then use rockets to get the rest of the way. And if you can’t do that, how can you hope to get anything self-sustaining to the moon? You’d need to get the industrial machinery to process the ores you found up there (let’s not worry about how you found the ores) into metal, etc.
Maybe you don’t need something the size of a steelmaking plant, but it ain’t gonna be small.
Urza
Humans think anything they see frequently is reality, and they see tv more often than actual reality for most people. Really anything at all. Human brain is wired to go with what it sees first and not worry if it makes a mistake. Anyone looking around at humanity today sees how often people are flat out wrong but just sticking with what they saw first or what agrees with them. SciFi should teach lessons and be inspirational towards trying to build those things, the number of inventions that came about because of Star Trek is quite high, but it helps they at least attempt to do believable science in many of the day to day things.
Side note the security conversations at work are straight out of Fast and Furious as if they happen on a regular basis and not just a purely hypothetical because people don’t know how to separate that fiction from real possibilities.
eclare
Thank you for this post. I got nothin.
Jay
@Chetan R Murthy:
C’mon.
You just need to build a tower close to the Karman Line, stick an elevator on all 4 sides, one for the rocket/launch pad,
Easy peasy.//
Aziz, light!
The most technical challenge of the trip to Mars is keeping cosmic radiation from shredding your DNA. That can be done with sufficient shielding (encasing living spaces in a thick blanket of water, for example) but shielding is so heavy that the ship would have to carry a very much larger volume of fuel to move it. Fuel is heavy, so you need more fuel to move it, see “Rocket Equation.” There’s also the damage that zero gravity does to your health, no matter how good your life support.
The nine-month trip is followed by a mandatory 16-to-24-month stay before there’s a return window to Earth. You still need protection from radiation, as Mars provides almost none, lacking both a magnetic field and an atmosphere (the planet’s unbreathable air is only one percent as dense as ours). The way to do this is to live entirely underground, emerging only for brief periods in very bulky spacesuits (not the stylish body-hugging one sported by Matt Damon). If you find living underground to be appealing, you can do that on Earth a lot more easily and cheaply.
All science fiction is fictional.
Chetan R Murthy
As Charlie Stross (amongst others) has said, people who wanna colonize Mars ought to start by successfully colonizing Antarctica with underground tunnel colonies. It’s hella more hospitable than Mars’ll be, and the supply chain issues are way, way easier to deal with. Figure out how to build entirely self-sustaining colonies underground on Antarctica, including finding ores, processing them, building the entire industrial plant needed for self-sustainment, and then, only then, maybe think about how to lift all of that to Mars. And how to deal with all the other issues (cosmic rays, air, poisonous regolith, gravity, and on and on and on).
Jay
@Chetan R Murthy:
None of the “Biodomes” worked, and that was above ground, on earth.
Funny that.
John Revolta
Mars ain’t the kind of place to raise your kids. In fact, it’s cold as hell.
Baud
Speaking of fiction.
Jay
@Baud:
It’s pretty clear that there was no attempt to “groom” the American Public with lies, for this war of choice, to try to divert attention from the Trump/Epstein files
Murdering 158 Elementary school girls to try to divert attention from the rape of thousands of Elementary School girls by the Epstein Class that rules the USA.
Viva BrisVegas
Send Grok to Mars first.
Ten Bears
Speaking of Mars … the Epstein Files
OK, maybe not the Epstein Files but a big distraction none-the-less
Just think of all the problems all that money could solve right here
Though it was funny when Leon skunked the venture investors …
Baud
Baud
I’m starting to think I’m never going to experience a holodeck.
SpaceUnit
@Baud:
You wouldn’t want to. The process sends your soul to hell before it replicates your physical being in this dimension.
SpaceUnit
Sorry, that was kind of dark. I’m currently involved with some local zoning law controversies in which people needing to go to hell is an ongoing theme.
Jay
@SpaceUnit:
When I worked at an industrial computer mfgr, we had an empty desk, “manned” by a fictitious employee, named Hellen Hunt.
Pete Downunder
@Aziz, light!: You are absolutely right. The rocket equation is unforgiving and exponential. Then figure out the fuel you need to get to Mars. The multiply by 4 – get up to speed to get there, slow down when you arrive and the same again going home. The shielding issue will add huge amounts of mass that also has to be accelerated. The zero gravity for 6-9 months will weaken muscles and bone mass. There will be no rescue, no emergency return. We are not sending people to Mars, not soon and probably not ever. Even that moron Musk has finally figured it out.
SpaceUnit
@Jay:
I thought she was awesome in Twister!
Baud
I blame Matt Damon.
Martin
@Jay: Can we at least blame Steve Bannon for that?
SpaceUnit
Also, what’s the point of telling someone that they need to go to hell? As if they’d take your suggestion and willingly go there of their own accord. I mean, telling someone that they belong in hell makes a lot more sense, conversationally speaking.
I might be overthinking this shit. It’s late and I ought to be in bed.
Jay
@SpaceUnit:
Punch line, ” You have to go to Helen Hunt for that!”
Baud
@SpaceUnit:
Makes me wonder how often people take the advice to go fuck themselves.
SpaceUnit
@Baud:
Probably more often than we want to think about. Mostly unrelated to the advice though.
SpaceUnit
@Jay:
I get it. Still like Twister though. That movie is a guilty pleasure.
Bruce K in ATH-GR
@Pete Downunder: I know The Martian is fiction, but Andy Weir did a lot of number crunching while writing the novel, and low-acceleration long-duration ion thrusters (which have been tested, but only in small scale) would change the rocket equations dramatically. However, without something like that in place on human-crewed-mission scale, yes, you’re still looking at the classic rocket equations.
Weir also admitted that he fudged the radiation shielding problem for the sake of the story.
So yeah, Mars is off the table until a bunch of new tech (that would have to be heavily subsidized, because there’s no quarterly profit from it) comes online. And given that it looks like we don’t have the infrastructure to return to the Moon at the moment, Mars is a pipe dream.
Bruce K in ATH-GR
@Baud: I’m less in favor of giving someone that directive, and more a fan of giving the offender instructions as to how. Specifically, how a serrated knife and a corkscrew can be used to help insert Tab D into Slot A. This only works with people who possess a Tab D, naturally.
NotMax
Even if one manged to survive the trip there and an extended stay – 26 months months until the next optimal journey time – in some kind of habitat (two dubious propositions), the trip back would certainly finish you off.
That radiation stuff ain’t chopped liver.
Pete Downunder
Baud
MagdaInBlack
@John Revolta: ❤️ Elton
( had a spiders from Mars moment there, then corrected myself)
Sure Lurkalot
@MagdaInBlack: Well, maybe Rocket Man was Major Tom.
Went down an internet wormhole the other day and watched a live performance of Heroes and got a bit teary. Bowie was seminal for me somehow.
Gloria DryGarden
Adding in the idea that calling someone a pu$sy, or a c*n+ as a curse, might perform the way curses usually do, by rebounding back to the sender, and suddenly the sender finds himself with an inadvertent sex change.
Gloria DryGarden
@Baud: Can I get my money back?
Betty Cracker
@Baud: The “several” claim appears to suggests a cause that isn’t a one-off, but the only vids I’ve seen show one plane in a tailspin and the pilot ejecting safely and appearing okay on the ground.
Hopefully the “several” claim is a “fog of war” phenomenon.
Baud
@Gloria DryGarden:
Transgender for everyone!
Baud
@Betty Cracker:
Yeah, the reddit thread I found that story at was debating between one and two planes caught on video. I don’t know what the evidence is for more than two. Even two would be a lot.
Gloria DryGarden
@Betty Cracker: this is the voice of calm and reason.
it helps, and I’m grateful.
Gloria DryGarden
@Baud: just so!
And, including, for misogynists!
Baud
@Betty Cracker:
@Gloria DryGarden:
Betty Cracker
Was just reading about the mass shooting in Austin (2 dead, plus the shooter, more than a dozen injured). The cops say there may be a “nexus” to terrorism because the shooter’s clothing and possibly something in his vehicle included items related to Iran, but there are also reports that the shooter (naturalized U.S. citizen from Senegal) had a history of mental health issues.
We’ll have to wait for more facts to come out about the incident. But it occurred to me, not for the first time, that our insane gun culture leaves us particularly vulnerable to mass shooting incidents related to state-actor terrorism, in addition to random violence perpetrated by armed nutcases.
Betty Cracker
@Baud: Oopsie! Thanks for the additional info. Glad to hear everyone was rescued safely.
Gin & Tonic
@Betty Cracker: Three, shot down by Kuwaiti air defense. Oopsie.
Gloria DryGarden
@Baud: now I have to read about “friendly fire”
because I don’t understand, I don’t study war, and the phrase seems an oxymoron.
Now I don’t just want my money back. I want people’s lives back. I don’t care if I’m being unreasonable.
Going on a related tangent now: My nephew was three when 9-11 happened. He stood in front on the television, watching that video of the plane flying straight into the tower, and screamed, and kept screaming. My sister, his mom, turned the tv off.
I wasn’t there, but the image was indelible for me. During certain kinds of news this year, I experience an internal sense of an endless screaming inside, much like my nephew. (Piercing and endless, like a car alarm, but with feeling)
Baud
@Gloria DryGarden:
Thankfully, Trump can’t blame the Kuwaitis because he loves their money. I just hope there are no black or female service members in the vicinity who can be scapegoated for this embarrassment.
Gloria DryGarden
@Baud: thank you
@Gin & Tonic: oopsie indeed.
prostratedragon
@Baud: Three friendly fire shootdowns? Hmm.
Gloria DryGarden
@Baud: oh goddess!
I shall join you in that hope.
prostratedragon
@Gloria DryGarden: Poor kid. Just old enough to get how terrible it was.
Baud
@Gloria DryGarden:
There is precedent.
prostratedragon
This story has gone mainstream, from the Guardian:
Of course, while not providing abortions there also are no adequate care facilities for very young mothers carrying to term.
Betty Cracker
@Gloria DryGarden: Our kiddo was also three when 9/11 happened but fortunately, unlike your nephew, super-oblivious to the whole thing. I often think of how those now young adults grew up in a largely dysfunctional country that was lurching from self-induced crisis to crisis.
The Obama years were a brief respite where hope for a better future seemed possible. But every accomplishment related to that time — healthcare, LGBTQ rights, etc. — is being clawed back in the worst way by the very worst people.
I don’t want to catastrophize — things were pretty fucked up when I was growing up too. Reagan was president when I was in high school! But there was a leftover sense of optimism about the future that had mostly evaporated by the time the next generation came of age. It’s depressing.
Gloria DryGarden
@prostratedragon: thank you. Very kind.
your brief comment echoes like a poem.
prostratedragon
Gregor Samsa update (NSF Awards through 2/27/26) 🧵
MagdaInBlack
@Betty Cracker: A friend and I were having a conversation the other day, about her grandkids. They were 4, 6, and 8 when trump was first elected, and the chaos of the “political situation” is all they’ve ever seen of government. The Biden 4 years were not exactly calm, even tho that’s what they aimed for, and even tho the administration was sane and rational.
prostratedragon
@Gloria DryGarden: Hope he likes some kind of art or craft. It helps.
Baud
@Betty Cracker:
@MagdaInBlack:
Too many people benefit from keeping folks depressed. Especially young folks.
MagdaInBlack
@Gloria DryGarden: I can certainly relate to your internal screaming. Lately I have dreams where I am screaming like that, but no sound comes out.
Yes, this shit gets to us, in ways we don’t recognize on the surface.
frosty
@Betty Cracker: Coming of age in the 60s wasn’t exactly calm and optimistic either. I think Obama’s eight years were it for us too.
OK Boomer.
prostratedragon
Very interesting thread:
@frosty: I haven’t recovered yet from 1968, a 36-month year.
Gloria DryGarden
@MagdaInBlack: yes. My blood pressure has changed, I may be on the verge of medical trouble. While having a glitch in my health care coverage arrangements.
Thank you for saying you relate.
This internal screaming, it’s the “ lives of silent desperation” on steroids, or 100x.
its a waking dream, for me. I hear it all day long, inside, some days.
Gloria DryGarden
@prostratedragon: he’s in his thirties, plays a string instrument, travels to see the northern lights. I think he’s turned out ok. I wish I knew my nephews better, because I’ve loved them since they were conceived.
Gloria DryGarden
@Betty Cracker: I notice a huge cognitive dissonance between the people who get how terrible some things have been, (sensitives, people of compassion and empathy, people who believe in loving your neighbor and helping your community)
and the desensitized sane washing people who lie, promote, Vote for or mete out harm.
For example contrast most of us here, with orange golfer man and his appointees in government. Caroline leavitt, vs Bishop Marian Budde. Etc
i’m Trying to compress this set of thoughts into a poem, but it’s not coming to me yet. The right poem will make the blind see, will strip the paint off of furniture, and rip the lies out of the lying ones, all the way to the roots, sort of like how the little mermaid lost her tongue. It’s strong stuff, but The ship needs to correct course, and that might be what it takes.
Gloria DryGarden
@Betty Cracker: im very curious about the younger adults, and their outlook, how the world looks like, how they navigate despair.
Gloria DryGarden
@prostratedragon: my older nephew’s wife sews resistance banners in chintz appliqué panels, and gets donations to send them to Minnesota, and ti Democratic congresspersons. She’s astonishingly crafty, while raising two young children.
trnc
LOL, that single (at this time) comment on the Long-Duration Life Support piece. Just when we think all the difficult issues have been addressed.
Professor Bigfoot
@trnc: Heinlein and Clarke had great imaginations; but even they couldn’t see just how hard space will try to kill you.
I think their analogy was the sea, and every sailor knows the sea is ALWAYS trying to kill you… but even there you at least have air to breathe.
I can’t blame those old guys; but we’ve learned a LOT since then.
‘Nauts* on the ISS work pretty much 24 hours a day to keep that little bubble of air and water going, and they are only a couple hundred miles away; and have constant resupply.
We’re humans, none of these problems are insoluble, but we ain’t nowhere near the solutions for most of them.
Yet, at least.
As in religion, there’s always the possibility of as-yet undiscovered physics.
ETA * Cosmo- and Astro-
trnc
Right?
Mars is actually not as bad, but it’s much further away, of course. If Elon, et al were serious about either one, they could prove by setting up a self sustaining colony in a currently uninhabitable place on earth. If they can’t make it work in, say, Antarctica without frequent supply shipments, good damn luck on another planet.
trnc
@prostratedragon:
Well, that’s just icing on the cake for those sick fucks.
Gloria DryGarden
@MagdaInBlack: am i following you on bluesky?
trnc
@Professor Bigfoot:
On the one hand, we’ve learned a lot of facts. OTOH, too many people seem unable to meaningfully process even the simplest ones, and we seem to be regressing in that area.
MagdaInBlack
@Gloria DryGarden: I don’t do the bluesky or any of the social media baits.
dr. luba
“Life support is the biggest technical obstacle to the human exploration of Mars.”
I still do not think this should stop us from sending Musk (and as many tech bros as we can fit in the spacecraft) to Mars RIGHT AWAY!!
Chris T.
@Chetan R Murthy:
Hey, a space elevator is a real, practical idea … provided you can somehow find the unobtainium from which to build the stalk.
Of course boredom during the ride up and down (for humans) would also be a problem… (see space.stackexchange.com/questions/5603/how-long-would-it-take-to-ride-to-the-top-of-a-space-elevator)
Trivia Man
@Chris T.: My dream of a space elevator is dead. I attended a ben bova lecture in 1982, he swore it would be technically feasible once we had a material strong enough for the cable. Carbon nano tubes are strong! I guess that’s not enough.
Paul in KY
@Peale: And they will hate each other and refuse to breed…
Paul in KY
@Chris T.: Once we come up with scrith, then all will be well.