14 ms·

The Shape of a Mars Mission

152 points by feross 2y ago

insane_dreamer 2y ago
An interesting and fun read along these lines that examines many aspects of colonizing Mars, is A City On Mars, by the Weinersmiths
- Robotbeat 2y ago
  Unfortunately, in spite of a lot of good material in it, it’s also deeply flawed.
  - beder 2y ago
    How so?
    - Robotbeat 2y ago
      1) researching the problems far more than the solutions. This creates the impression to the reader that these problems don’t have solutions when in fact they do. 2) treating Deudney as authoritative in the space field when he is, at best, a quack who writes bad science fiction scary stories and tries to pass it off as non-fiction.
credit_guy 2y ago
The premise of the article is not completely correct. Here's a mission profile created by NASA [1] that gets you to Mars quickly (185 days), lets you stay there for 30 days, then gets you back to Earth quickly (250 days). The departure date is 7-Apr-2033. [1] https://trajbrowser.arc.nasa.gov/traj_browser.php?NEAs=on&NECs=on&chk_maxMag=on&maxMag=25&chk_maxOCC=on&maxOCC=4&chk_target_list=on&target_list=Mars&mission_class=roundtrip&mission_type=rendezvous&LD1=2030&LD2=2035&maxDT=1.5&DTunit=yrs&maxDV=14.0&min=DT&wdw_width=365&submit=Search#a_load_results https://trajbrowser.arc.nasa.gov/traj_browser.php?NEAs=on&NE...
rhcom2 2y ago
> The only way to explore Mars in our lifetime is to ditch the requirement that people accompany the machinery. It just doesn't make sense to me to send humans. Exhaust the science collection of robots first.
- keiferski 2y ago
  The budget and general public interest will be 1000x greater if humans are sent. “Robots explore Mars” is a daily news highlight. “First humans land on Mars” is a global historical event.
  - whiplash451 2y ago
    General public interest will vanish once people realize that the journey will last two years and likely start 30 years from now. Oh, and they won't see the event live anywways. The trip to the Moon was a free trip to Jurassic Park in comparison.
- oceanplexian 2y ago
  If that's the case then what is the point? If you think robots should do everything then you might as well retire the human race. Why even bother to live. Why explore the stars when you can get a robot to do it for you?
  - 0_____0 2y ago
    If the goal is "put man on Mars" then that's what you gotta do. It's harder to make the argument that you need to do that in the service of science, or even offworld colonies, given the unsuitability and impracticality of those both.
    - lmm 2y ago
      What plausible path is there to offworld colonies without sending humans?
NegativeLatency 2y ago
Would love to see a (robotic) sample return mission, pick up some of the piles of specimens from one of the rovers. Sounds potentially horrific to test with humans: > able to communicate home by radio, but forced by unalterable cycles of nature to wait months or years for a rescue ship.
- decimalenough 2y ago
  Eh, we've done it before. Read up on Magellan's circumnavigation, the colonization of Australia or the Shackleton era of Antarctic exploration. Of course, the difference is that compared to the conditions that await on Mars, a roaring blizzard on Antarctica is a balmy spring day. The air may be cold but at least it's breathable.
  - somenameforme 2y ago
    I'm not sure that comparison is as obvious as it might seem. Because while the air is unbreathable on Mars, the most violent weather would be pretty much harmless. A roaring blizzard in Antarctica could actually directly damage facilities with force. This was one of the very few things that was intentionally faked in "The Martian." The whole 'violent dust storm' that sets off the crisis of the movie doesn't exist. Low atmospheric pressure means that dust storm would have felt like a slight breeze, at most. I think it's quite noteworthy that a hard sci-fi book ended up having to turn to fiction to create a crisis on Mars!
    - buck746 2y ago
      The reduced air pressure on mars also means keeping warm will be significantly easier than in Antarctica. Convective heat transfer is much slower. Protecting against conduction isn't too challenging. Seeing how a spacesuit is necessary on mars building one that can retain enough heat to be comfortable isn't really a herculean effort. Far easier than a suit for the moon, mars doesn't really have grains of regolith that are consistently sharp and abrasive like earths moon has. On mars there's more a fine powdery substance, it was called "fines" in the red mars novel. It's irritating to see people claim it's colder than antarctica but never a discussion how the reduced atmospheric pressure makes it easier to keep warm.
trhway 2y ago
napkin for ion drive powered by solar - tech available today (and nuclear as the power source for the ion drive instead of the solar - tomorrow for Mars and beyond) - looks much better than chemical even for Mars. As SpaceX already using ion drives on Starlinks, and the SpaceX will be the one going to Mars, i'd expect that it will be ion drive.
- idlewords 2y ago
  Solar electric propulsion has great specific impulse [i.e., efficient use of propellant] but very low thrust. You're forever spiraling away from and then down into gravity wells. It's terrific for cargo, but not viable for crews.
  - trhway 2y ago
    not forever. You can get to Mars faster than with chemical, something under 90 days one way in some reasonable configurations.
    - zardo 2y ago
      What does that look like? A ten ton ship including 100 square miles of solar panels?
      - deleted 2y ago
        [deleted]
      - trhway 2y ago
        You need about 10KWt per 100kg, i.e. 50m2 of panels. For 10 tons it would be under 5000m2, ie. like 70x70m. The panels do need to be relatively thin. Less than half the mass - 4 tons is the expelled mass (using say those NASA drives with 3500 Isp). And if you get panels at 0.5kg/m2, you'd get to 15km/s in under 2 months with about 3.5 tons for the rest of the ship including payload. More panels - either thinner ones or with less payload - faster time to Mars. Nuclear with ion drive - even better (and the only choice beyond Mars), can get you 35km/s+ (Voyager) or like 70km/s+ with 2 stages in under year.
oceanplexian 2y ago
The author puts a Mars mission into a realistic perspective but also, I think there are people who are wired differently than they are. I'm not a test pilot but I'm a licensed pilot and I'd sign up for a Mars mission in a heartbeat, even if there was a 70% chance of success. We send people under the ocean for years at a time to live on nuclear submarines in arguable more dangerous and isolated circumstances and they don't blink at the opportunity. To be the first person on another planet? What an incredible, fantastic opportunity. I feel like we will need to return to a place (As a society) where we accept risks that push the boundaries of the human race. Something we had a lot of in the 1960s but not a lot of today.
- bigbacaloa 2y ago
  [dead]
- croes 2y ago
  It wasn't about pushing boundaries, it was about beating the USSR.
- Jabbles 2y ago
  > years at a time I don't think any single crew deployment reaches a year. > more dangerous and isolated circumstances I think Mars is massively more dangerous and isolated. A submarine can plausibly return to port or surface to breathable air. There is no such option on Mars. Nuclear submarines are much larger than spacecraft and have much more room for comfort options. They have a much larger crew, and the knowledge that this happens all the time from many nations must be of some comfort.
  - m4rtink 2y ago
    IIRC British antarctic service does uninterrupted 2 yer contracts. Not Mars or a submarine but still 2 years.
    - Cthulhu_ 2y ago
      At least being outside doesn't kill you in those ones. There's also earthbound experiments like Nasa's CHAPEA programs (https://www.nasa.gov/news-release/martians-wanted-nasa-opens-call-for-simulated-yearlong-mars-mission/ https://www.nasa.gov/news-release/martians-wanted-nasa-opens...) but they only go up to about a year.
ETH_start 2y ago
I reluctantly upvoted this for the wealth of scientific/engineering knowledge it contains despite strongly disagreeing with some of its conclusions: -- In recent years, there’s been a remarkable division in space exploration. On one side of the divide are missions like Curiosity, James Webb, Gaia, or Euclid that are making new discoveries by the day. These projects have clearly defined goals and a formidable record of discovery. On the other side, there is the International Space Station and the now twenty-year old effort to return Americans to the moon. These projects have no purpose other than perpetuating a human presence in space, and they eat through half the country’s space budget with nothing to show for it. Forget even Mars—we are further from landing on the Moon today than we were in 1965. In going to Mars, we have a choice about which side of this ledger to be on. We can go aggressively explore the planet with robots, benefiting from an ongoing revolution in automation and software to launch ever more capable missions to the places most likely to harbor life. Or we can stay on the treadmill we’ve been on for forty years, slowly building up the capacity to land human beings on the safest possible piece of Martian real estate, where they will leave behind a plaque and a flag. But we can’t do both. -- 1. SpaceX/Starship lower the cost of human space exploration by possibly two orders of magnitude over the Apollo/Space-Shuttle era 2. We can increase the amount of resources allocated to space exploration. For both of these reasons, we absolutely can pursue both tracks.
- somenameforme 2y ago
  I remained neutral on it since I also thought it was an interesting and clearly well researched article, but I think it leaned a bit too heavily on some somewhat inappropriate analogs to things like like with the ISS. It's a deteriorating old station where astronauts need to constantly prepare for orbital reboosts, receiving cargo, running commercial experiments, literally plugging holes more recently, and so on. This doesn't really translate meaningfully to the responsibilities on an interplanetary mission on new hardware. Similarly alot of his stuff about microgravity just handwaves away the fact that a lot of the mission will be spent in 0.3g. And, in terms of overall effects on the body 0.3g will almost certainly end up being closer to 1g than 0g. It'll make it much easier to do things like exercise and all the "normal" physics of things would be much closer to the environment we all evolved in, than in 0g where everything just gets super funky. In fact I wonder about the viability of simply wearing body weights while on Mars, something that obviously would not work in 0g. The radiation stuff has also been pretty well researched and isn't likely to be a show-stopper, especially with normal measures for protection like using the water supplies as a shield.
maxglute 2y ago
Has there been discussions on who to send on a "man"ned mission? Apollo had height and weight limitations for an average male, and now that DEI is dead, I wonder if it's more prudent to proritize sending smaller people (really light women) because sexual dimorphism seems to be a thing in the military.
- Qem 2y ago
  She would surely be an awesome astronaut candidate, if she were alive today: https://en.m.wikipedia.org/wiki/Luc%C3%ADa_Z%C3%A1rate https://en.m.wikipedia.org/wiki/Luc%C3%ADa_Z%C3%A1rate
- somenameforme 2y ago
  Women tend to be substantially more susceptible to radiation related issues. [1] In reality though I think the main issue (outside of competence/merit) will be making sure people stay psychologically sound being tens of millions of miles away from Earth, for years. So in that case I wouldn't be surprised if they end up prioritizing highly capable couples. [1] - https://pmc.ncbi.nlm.nih.gov/articles/PMC6509159/ https://pmc.ncbi.nlm.nih.gov/articles/PMC6509159/
  - Cthulhu_ 2y ago
    I'm no psychologist but sending couples is a really bad idea. It's a mission, not a Big Brother style relationship test. If they do intend to send couples, put them in a small room for a year first as part of their training and selection process.
  - maxglute 2y ago
    I think if long term supplies bottleneck, one would pick for physiology that requires less, i.e. 100lb person consumes ~50-60% calories as 200lb person. Or for same supplies you get much more brains/work done. Light lesbians with no need to worry about pregnacy fits the bill.
schiffern 2y ago
Aluminum is a poor material choice for thick radiation shielding, since it produces lots of secondary radiation and it's inefficient due to its high atomic mass. Polyethylene, which is nice and hydrogen-rich, is widely understood to be superior. An aluminum hull is nice because it does double duty, but you don't need to make it thicker than the structure requires just for radiation purposes. Instead you would add internal shielding. It's also smart to use food (and the resulting waste) and other consumables as shielding, since you need to carry that mass anyway.
- somenameforme 2y ago
  Water is a big one. Missions to Mars will be carrying tons of it, and it's an absolutely excellent radiation shield.
- idlewords 2y ago
  I think you misunderstood a diagram; grams of Al per square centimeter is a standardized unit of shielding in the literature, not an engineering choice.
  - schiffern 2y ago
    That doesn't matter though. Since it's not representative of the real shielding, it's an inapplicable standard to use for this problem. You should realize that there's no simple way to convert from aluminum to polyethylene: it's not as simple as "PE is X times better." Due to secondaries aluminum stops improving after 30 g/cm^2,[1] hence why their chart (bottom line) levels out. PE doesn't have that problem, and lower dose rates are achievable versus what the author states. TL;DR regardless of if you call it a "standard" or not, the author is still using bad math to overstate the actual risk. [1] Figure 3, solid black line https://ntrs.nasa.gov/api/citations/20170005580/downloads/20170005580.pdf https://ntrs.nasa.gov/api/citations/20170005580/downloads/20...
    - idlewords 2y ago
      I didn't choose AL shielding as the reference standard to use in the literature; I'm sorry it bugs you. You can read the author's other work, that goes into great detail about different types of shielding, if you want to gain confidence in his math. The upshot is you need many meters of polyethylene to effectively shield the heavy ion component of GCR, which is what the fuss is about. But the point of that particular diagram is not shielding, but to illustrate the 2-3x uncertainty in estimates of tumor risk based on our poor understanding of high-Z ion exposure.
verzali 2y ago
This is a very good article. It really puts the frustration I have with Musk's constant "we're going to Mars" in context. Yes, a big rocket is necessary prerequisite for Mars. No, it is not the only problem you need to solve. And also having worked with the reality of human spaceflight operations, we are just not ready yet to send a spacecraft into deep space for months on end. It's easy to throw out blithe statements that we "just need a big spaceship", or we'll use ion drives or some other such tech, but the reality is way more messy than that. We just aren't ready yet and we won't be for some time.
- lapcat 2y ago
  > It really puts the frustration I have with Musk's constant "we're going to Mars" in context. This is just the latest version of The Music Man and Marge vs. the Monorail. Musk is serious about getting rich but not about going to Mars. It's always been a ploy to trick naive tech nerds into sacrificing themselves for the goal of "saving the world". Tesla is a perfect example of this. A low-cost no-frills electric car would do a lot more for the environment than the vehicles produced by Tesla, which are luxury-priced and continue to (falsely) promise "Full Self Driving". The market is obvious: well-off tech nerds who are made to feel good about themselves that their luxury purchase, with cool technology, is "saving the Earth". (A similar strategy is used by Apple, by the way. Apple convinces people that buying a new iPhone every year or few years is "carbon neutral" and that it's somehow ok to eschew device repairability, upgradability, user battery replacement, etc.) We're told that the plan was to sell cheaper Teslas "later". It's always later. Yet other auto manufacturers have produced cheaper electric vehicles without the self-driving crap, and still for Tesla it's "later". So Musk has $44 billion to spend on Twitter but not on taking lower margins on Tesla vehicles? We're told now, by Musk, that the biggest barrier to the Mars project is not, say, the gravity on Mars, or the radiation, but rather "the woke mind virus". Uh huh. Con man. I'm not denying Musk's accomplishments, any more than I'm denying that Trump managed to get himself elected POTUS twice. But they're both con men, and their real goals—power, self-enrichment, self-aggrandizement—have never been the same as what they tell to their followers. They're surely among the best con men on the planet. It feels like all of the top con men are coming together now for the big heist, like Ocean's Eleven.
PaulHoule 2y ago
I'm picturing that the safe way forward is to send a 1000 day duration mission to LEO which would remain autonomous except in case of critical failure. Probably a series of them.
- somenameforme 2y ago
  The article was very misleading there. The astronauts will only be in 0g for several months, at most. After that they'll be on Mars with its 0.3g which will be much more similar to Earth. Valery Polyakov [1] stayed in space for 438 days which is dramatically longer than any sort of normal transit period to or from Mars. He not only suffered 0 major issues from such a stay, but even briefly walked on Earth immediately after landing precisely to demonstrate that he would be fit to work on Mars even after that sort of time period. There were never any efforts to surpass that stay because it's completely unnecessary. [1] https://en.wikipedia.org/wiki/Valeri_Polyakov https://en.wikipedia.org/wiki/Valeri_Polyakov
jpm_sd 2y ago
Don't miss part 1 (2023) for context. https://idlewords.com/2023/1/why_not_mars.htm https://idlewords.com/2023/1/why_not_mars.htm Seems like the most conservative approach would be to send the return vehicle first, empty. Once it's landed safely on Mars and all systems look good, it would be reasonable to send the human crew in a 2nd vehicle?
- ckemere 2y ago
  I had the same thought, but this has no effect on necessary delta-V. In terms of risk, I suspect it's already baked in to his analysis at some level. The risk comes from human-time-on-planet or time-in-space, which having a return vehicle doesn't change.
- somenameforme 2y ago
  The mission plan has always involved sending a series of unmanned ships first. This is not only to deploy supplies and other necessities ahead of time, but to make sure we can actually safely land. People are kind of taking that latter part for granted because of all SpaceX has achieved, but it will itself be a historic event. We've never landed anything on Mars except tiny little rovers generally less than a ton each. And here we're talking about landing a rocket with a payload that will ideally be in the hundreds of tons, let alone the mass of the rocket itself!
tagami 2y ago
a variable not covered: mental well being on the long voyage.
- buck746 2y ago
  That's where a larger group helps versus the 3 men on Apollo, or 4 people for Artemis. Having a larger pool of personal will ease a lot of social friction. It's also likely that a laser comms connection will be readily available, that is a large part of why starlink developed laser link between satellites. I expect before people go that SpaceX will put a small constellation of starlink satellites in orbit of mars. I could also see them putting a bunch of probes on a starship and having them separate in martian orbit, landing at candidate sites. The combination of the 2 will lead to a lot of valuable data to decide where humans will land first. Around mars it's likely the satellites will be in a higher orbit, but there's no internet needing low latency there either, at least not at first. They could be a basis for a mars positioning system. If a lower orbit is used they could potentially use synthetic aperture radar to get high resolution scans of the surface. It's probable that many starships will already be waiting on the surface by the time humans make the trek out there. Presumably loaded with food, equipment parts etc... For how quickly the ships are fabricated we aren't looking at a scenario where ships are in short supply.
potato3732842 2y ago
During the second world war the British not so famously (it's not like it's something you brag about) spent a lot of money and effort building extremely heavy tanks or assault guns designed to help a spearhead a breach of the Siegfried line. They turned out to be mostly unnecessary due to a combination of factors that can be roughly summed up as "quantity has a quality all its own" and the projects were steadily cancelled as the war in Europe wound down. It's likely that some of these big unknown problems will similarly evaporate or prove to be easily solved once we actually do stuff like put humans in deep space ad on the moon for serious chunks of time.
thomascountz 2y ago
I think this quote sums up the monumental difficulties nicely: You can think of flying to Mars like one of those art films where the director has to shoot the movie in a single take. Even if no scene is especially challenging, the requirement that everything go right sequentially, with no way to pause or reshoot, means that even small risks become unacceptable in the aggregate. By now, a lot of individual problems needing to be solved for a Mars mission have sound solutions! But taken in aggregate, it's unbelievable to me that one could simply believe we're ready. We've done life support in LEO for decades, we can use Mars' nitrogen-rich atmosphere, we can pack a bunch of rockets with supplies! Yes we did and yes we could and yes we very well may! But, as the article makes clear, the engineering challenge ahead isn't in having all the puzzle pieces flipped right-side up, it's in putting the thing together and keeping it together during a wind storm.
foobarbecue 2y ago
"The closest thing humanity has built to a Mars-bound spacecraft is the International Space Station." Mariner, Viking, Odyssey, MRO, Maven, MEX, TGO, MER, Curiosity, Insight, Zhurong, Perseverance, Ingenuity all over there like HELLO!? But yeah, I know they meant to say "crewed" ... and the rest of this article seems accurate.

152 points by feross 2y ago

An interesting and fun read along these lines that examines many aspects of colonizing Mars, is A City On Mars, by the Weinersmiths

Robotbeat 2y ago
Unfortunately, in spite of a lot of good material in it, it’s also deeply flawed.
- beder 2y ago
  How so?
  - Robotbeat 2y ago
    1) researching the problems far more than the solutions. This creates the impression to the reader that these problems don’t have solutions when in fact they do. 2) treating Deudney as authoritative in the space field when he is, at best, a quack who writes bad science fiction scary stories and tries to pass it off as non-fiction.

credit_guy 2y ago

The premise of the article is not completely correct. Here's a mission profile created by NASA [1] that gets you to Mars quickly (185 days), lets you stay there for 30 days, then gets you back to Earth quickly (250 days). The departure date is 7-Apr-2033. [1] https://trajbrowser.arc.nasa.gov/traj_browser.php?NEAs=on&NECs=on&chk_maxMag=on&maxMag=25&chk_maxOCC=on&maxOCC=4&chk_target_list=on&target_list=Mars&mission_class=roundtrip&mission_type=rendezvous&LD1=2030&LD2=2035&maxDT=1.5&DTunit=yrs&maxDV=14.0&min=DT&wdw_width=365&submit=Search#a_load_results https://trajbrowser.arc.nasa.gov/traj_browser.php?NEAs=on&NE...

rhcom2 2y ago

> The only way to explore Mars in our lifetime is to ditch the requirement that people accompany the machinery. It just doesn't make sense to me to send humans. Exhaust the science collection of robots first.

keiferski 2y ago
The budget and general public interest will be 1000x greater if humans are sent. “Robots explore Mars” is a daily news highlight. “First humans land on Mars” is a global historical event.
- whiplash451 2y ago
  General public interest will vanish once people realize that the journey will last two years and likely start 30 years from now. Oh, and they won't see the event live anywways. The trip to the Moon was a free trip to Jurassic Park in comparison.
oceanplexian 2y ago
If that's the case then what is the point? If you think robots should do everything then you might as well retire the human race. Why even bother to live. Why explore the stars when you can get a robot to do it for you?
- 0_____0 2y ago
  If the goal is "put man on Mars" then that's what you gotta do. It's harder to make the argument that you need to do that in the service of science, or even offworld colonies, given the unsuitability and impracticality of those both.
  - lmm 2y ago
    What plausible path is there to offworld colonies without sending humans?

NegativeLatency 2y ago

Would love to see a (robotic) sample return mission, pick up some of the piles of specimens from one of the rovers. Sounds potentially horrific to test with humans: > able to communicate home by radio, but forced by unalterable cycles of nature to wait months or years for a rescue ship.

decimalenough 2y ago
Eh, we've done it before. Read up on Magellan's circumnavigation, the colonization of Australia or the Shackleton era of Antarctic exploration. Of course, the difference is that compared to the conditions that await on Mars, a roaring blizzard on Antarctica is a balmy spring day. The air may be cold but at least it's breathable.
- somenameforme 2y ago
  I'm not sure that comparison is as obvious as it might seem. Because while the air is unbreathable on Mars, the most violent weather would be pretty much harmless. A roaring blizzard in Antarctica could actually directly damage facilities with force. This was one of the very few things that was intentionally faked in "The Martian." The whole 'violent dust storm' that sets off the crisis of the movie doesn't exist. Low atmospheric pressure means that dust storm would have felt like a slight breeze, at most. I think it's quite noteworthy that a hard sci-fi book ended up having to turn to fiction to create a crisis on Mars!
  - buck746 2y ago
    The reduced air pressure on mars also means keeping warm will be significantly easier than in Antarctica. Convective heat transfer is much slower. Protecting against conduction isn't too challenging. Seeing how a spacesuit is necessary on mars building one that can retain enough heat to be comfortable isn't really a herculean effort. Far easier than a suit for the moon, mars doesn't really have grains of regolith that are consistently sharp and abrasive like earths moon has. On mars there's more a fine powdery substance, it was called "fines" in the red mars novel. It's irritating to see people claim it's colder than antarctica but never a discussion how the reduced atmospheric pressure makes it easier to keep warm.

trhway 2y ago

napkin for ion drive powered by solar - tech available today (and nuclear as the power source for the ion drive instead of the solar - tomorrow for Mars and beyond) - looks much better than chemical even for Mars. As SpaceX already using ion drives on Starlinks, and the SpaceX will be the one going to Mars, i'd expect that it will be ion drive.

idlewords 2y ago
Solar electric propulsion has great specific impulse [i.e., efficient use of propellant] but very low thrust. You're forever spiraling away from and then down into gravity wells. It's terrific for cargo, but not viable for crews.
- trhway 2y ago
  not forever. You can get to Mars faster than with chemical, something under 90 days one way in some reasonable configurations.
  - zardo 2y ago
    What does that look like? A ten ton ship including 100 square miles of solar panels?
    - deleted 2y ago
      [deleted]
    - trhway 2y ago
      You need about 10KWt per 100kg, i.e. 50m2 of panels. For 10 tons it would be under 5000m2, ie. like 70x70m. The panels do need to be relatively thin. Less than half the mass - 4 tons is the expelled mass (using say those NASA drives with 3500 Isp). And if you get panels at 0.5kg/m2, you'd get to 15km/s in under 2 months with about 3.5 tons for the rest of the ship including payload. More panels - either thinner ones or with less payload - faster time to Mars. Nuclear with ion drive - even better (and the only choice beyond Mars), can get you 35km/s+ (Voyager) or like 70km/s+ with 2 stages in under year.

oceanplexian 2y ago

The author puts a Mars mission into a realistic perspective but also, I think there are people who are wired differently than they are. I'm not a test pilot but I'm a licensed pilot and I'd sign up for a Mars mission in a heartbeat, even if there was a 70% chance of success. We send people under the ocean for years at a time to live on nuclear submarines in arguable more dangerous and isolated circumstances and they don't blink at the opportunity. To be the first person on another planet? What an incredible, fantastic opportunity. I feel like we will need to return to a place (As a society) where we accept risks that push the boundaries of the human race. Something we had a lot of in the 1960s but not a lot of today.

bigbacaloa 2y ago
[dead]
croes 2y ago
It wasn't about pushing boundaries, it was about beating the USSR.
Jabbles 2y ago
> years at a time I don't think any single crew deployment reaches a year. > more dangerous and isolated circumstances I think Mars is massively more dangerous and isolated. A submarine can plausibly return to port or surface to breathable air. There is no such option on Mars. Nuclear submarines are much larger than spacecraft and have much more room for comfort options. They have a much larger crew, and the knowledge that this happens all the time from many nations must be of some comfort.
- m4rtink 2y ago
  IIRC British antarctic service does uninterrupted 2 yer contracts. Not Mars or a submarine but still 2 years.
  - Cthulhu_ 2y ago
    At least being outside doesn't kill you in those ones. There's also earthbound experiments like Nasa's CHAPEA programs (https://www.nasa.gov/news-release/martians-wanted-nasa-opens-call-for-simulated-yearlong-mars-mission/ https://www.nasa.gov/news-release/martians-wanted-nasa-opens...) but they only go up to about a year.

ETH_start 2y ago

I reluctantly upvoted this for the wealth of scientific/engineering knowledge it contains despite strongly disagreeing with some of its conclusions: -- In recent years, there’s been a remarkable division in space exploration. On one side of the divide are missions like Curiosity, James Webb, Gaia, or Euclid that are making new discoveries by the day. These projects have clearly defined goals and a formidable record of discovery. On the other side, there is the International Space Station and the now twenty-year old effort to return Americans to the moon. These projects have no purpose other than perpetuating a human presence in space, and they eat through half the country’s space budget with nothing to show for it. Forget even Mars—we are further from landing on the Moon today than we were in 1965. In going to Mars, we have a choice about which side of this ledger to be on. We can go aggressively explore the planet with robots, benefiting from an ongoing revolution in automation and software to launch ever more capable missions to the places most likely to harbor life. Or we can stay on the treadmill we’ve been on for forty years, slowly building up the capacity to land human beings on the safest possible piece of Martian real estate, where they will leave behind a plaque and a flag. But we can’t do both. -- 1. SpaceX/Starship lower the cost of human space exploration by possibly two orders of magnitude over the Apollo/Space-Shuttle era 2. We can increase the amount of resources allocated to space exploration. For both of these reasons, we absolutely can pursue both tracks.

somenameforme 2y ago
I remained neutral on it since I also thought it was an interesting and clearly well researched article, but I think it leaned a bit too heavily on some somewhat inappropriate analogs to things like like with the ISS. It's a deteriorating old station where astronauts need to constantly prepare for orbital reboosts, receiving cargo, running commercial experiments, literally plugging holes more recently, and so on. This doesn't really translate meaningfully to the responsibilities on an interplanetary mission on new hardware. Similarly alot of his stuff about microgravity just handwaves away the fact that a lot of the mission will be spent in 0.3g. And, in terms of overall effects on the body 0.3g will almost certainly end up being closer to 1g than 0g. It'll make it much easier to do things like exercise and all the "normal" physics of things would be much closer to the environment we all evolved in, than in 0g where everything just gets super funky. In fact I wonder about the viability of simply wearing body weights while on Mars, something that obviously would not work in 0g. The radiation stuff has also been pretty well researched and isn't likely to be a show-stopper, especially with normal measures for protection like using the water supplies as a shield.

maxglute 2y ago

Has there been discussions on who to send on a "man"ned mission? Apollo had height and weight limitations for an average male, and now that DEI is dead, I wonder if it's more prudent to proritize sending smaller people (really light women) because sexual dimorphism seems to be a thing in the military.

Qem 2y ago
She would surely be an awesome astronaut candidate, if she were alive today: https://en.m.wikipedia.org/wiki/Luc%C3%ADa_Z%C3%A1rate https://en.m.wikipedia.org/wiki/Luc%C3%ADa_Z%C3%A1rate
somenameforme 2y ago
Women tend to be substantially more susceptible to radiation related issues. [1] In reality though I think the main issue (outside of competence/merit) will be making sure people stay psychologically sound being tens of millions of miles away from Earth, for years. So in that case I wouldn't be surprised if they end up prioritizing highly capable couples. [1] - https://pmc.ncbi.nlm.nih.gov/articles/PMC6509159/ https://pmc.ncbi.nlm.nih.gov/articles/PMC6509159/
- Cthulhu_ 2y ago
  I'm no psychologist but sending couples is a really bad idea. It's a mission, not a Big Brother style relationship test. If they do intend to send couples, put them in a small room for a year first as part of their training and selection process.
- maxglute 2y ago
  I think if long term supplies bottleneck, one would pick for physiology that requires less, i.e. 100lb person consumes ~50-60% calories as 200lb person. Or for same supplies you get much more brains/work done. Light lesbians with no need to worry about pregnacy fits the bill.

schiffern 2y ago

Aluminum is a poor material choice for thick radiation shielding, since it produces lots of secondary radiation and it's inefficient due to its high atomic mass. Polyethylene, which is nice and hydrogen-rich, is widely understood to be superior. An aluminum hull is nice because it does double duty, but you don't need to make it thicker than the structure requires just for radiation purposes. Instead you would add internal shielding. It's also smart to use food (and the resulting waste) and other consumables as shielding, since you need to carry that mass anyway.

somenameforme 2y ago
Water is a big one. Missions to Mars will be carrying tons of it, and it's an absolutely excellent radiation shield.
idlewords 2y ago
I think you misunderstood a diagram; grams of Al per square centimeter is a standardized unit of shielding in the literature, not an engineering choice.
- schiffern 2y ago
  That doesn't matter though. Since it's not representative of the real shielding, it's an inapplicable standard to use for this problem. You should realize that there's no simple way to convert from aluminum to polyethylene: it's not as simple as "PE is X times better." Due to secondaries aluminum stops improving after 30 g/cm^2,[1] hence why their chart (bottom line) levels out. PE doesn't have that problem, and lower dose rates are achievable versus what the author states. TL;DR regardless of if you call it a "standard" or not, the author is still using bad math to overstate the actual risk. [1] Figure 3, solid black line https://ntrs.nasa.gov/api/citations/20170005580/downloads/20170005580.pdf https://ntrs.nasa.gov/api/citations/20170005580/downloads/20...
  - idlewords 2y ago
    I didn't choose AL shielding as the reference standard to use in the literature; I'm sorry it bugs you. You can read the author's other work, that goes into great detail about different types of shielding, if you want to gain confidence in his math. The upshot is you need many meters of polyethylene to effectively shield the heavy ion component of GCR, which is what the fuss is about. But the point of that particular diagram is not shielding, but to illustrate the 2-3x uncertainty in estimates of tumor risk based on our poor understanding of high-Z ion exposure.

verzali 2y ago

This is a very good article. It really puts the frustration I have with Musk's constant "we're going to Mars" in context. Yes, a big rocket is necessary prerequisite for Mars. No, it is not the only problem you need to solve. And also having worked with the reality of human spaceflight operations, we are just not ready yet to send a spacecraft into deep space for months on end. It's easy to throw out blithe statements that we "just need a big spaceship", or we'll use ion drives or some other such tech, but the reality is way more messy than that. We just aren't ready yet and we won't be for some time.

lapcat 2y ago
> It really puts the frustration I have with Musk's constant "we're going to Mars" in context. This is just the latest version of The Music Man and Marge vs. the Monorail. Musk is serious about getting rich but not about going to Mars. It's always been a ploy to trick naive tech nerds into sacrificing themselves for the goal of "saving the world". Tesla is a perfect example of this. A low-cost no-frills electric car would do a lot more for the environment than the vehicles produced by Tesla, which are luxury-priced and continue to (falsely) promise "Full Self Driving". The market is obvious: well-off tech nerds who are made to feel good about themselves that their luxury purchase, with cool technology, is "saving the Earth". (A similar strategy is used by Apple, by the way. Apple convinces people that buying a new iPhone every year or few years is "carbon neutral" and that it's somehow ok to eschew device repairability, upgradability, user battery replacement, etc.) We're told that the plan was to sell cheaper Teslas "later". It's always later. Yet other auto manufacturers have produced cheaper electric vehicles without the self-driving crap, and still for Tesla it's "later". So Musk has $44 billion to spend on Twitter but not on taking lower margins on Tesla vehicles? We're told now, by Musk, that the biggest barrier to the Mars project is not, say, the gravity on Mars, or the radiation, but rather "the woke mind virus". Uh huh. Con man. I'm not denying Musk's accomplishments, any more than I'm denying that Trump managed to get himself elected POTUS twice. But they're both con men, and their real goals—power, self-enrichment, self-aggrandizement—have never been the same as what they tell to their followers. They're surely among the best con men on the planet. It feels like all of the top con men are coming together now for the big heist, like Ocean's Eleven.

PaulHoule 2y ago

I'm picturing that the safe way forward is to send a 1000 day duration mission to LEO which would remain autonomous except in case of critical failure. Probably a series of them.

somenameforme 2y ago
The article was very misleading there. The astronauts will only be in 0g for several months, at most. After that they'll be on Mars with its 0.3g which will be much more similar to Earth. Valery Polyakov [1] stayed in space for 438 days which is dramatically longer than any sort of normal transit period to or from Mars. He not only suffered 0 major issues from such a stay, but even briefly walked on Earth immediately after landing precisely to demonstrate that he would be fit to work on Mars even after that sort of time period. There were never any efforts to surpass that stay because it's completely unnecessary. [1] https://en.wikipedia.org/wiki/Valeri_Polyakov https://en.wikipedia.org/wiki/Valeri_Polyakov

jpm_sd 2y ago

Don't miss part 1 (2023) for context. https://idlewords.com/2023/1/why_not_mars.htm https://idlewords.com/2023/1/why_not_mars.htm Seems like the most conservative approach would be to send the return vehicle first, empty. Once it's landed safely on Mars and all systems look good, it would be reasonable to send the human crew in a 2nd vehicle?

ckemere 2y ago
I had the same thought, but this has no effect on necessary delta-V. In terms of risk, I suspect it's already baked in to his analysis at some level. The risk comes from human-time-on-planet or time-in-space, which having a return vehicle doesn't change.
somenameforme 2y ago
The mission plan has always involved sending a series of unmanned ships first. This is not only to deploy supplies and other necessities ahead of time, but to make sure we can actually safely land. People are kind of taking that latter part for granted because of all SpaceX has achieved, but it will itself be a historic event. We've never landed anything on Mars except tiny little rovers generally less than a ton each. And here we're talking about landing a rocket with a payload that will ideally be in the hundreds of tons, let alone the mass of the rocket itself!

tagami 2y ago

a variable not covered: mental well being on the long voyage.

buck746 2y ago
That's where a larger group helps versus the 3 men on Apollo, or 4 people for Artemis. Having a larger pool of personal will ease a lot of social friction. It's also likely that a laser comms connection will be readily available, that is a large part of why starlink developed laser link between satellites. I expect before people go that SpaceX will put a small constellation of starlink satellites in orbit of mars. I could also see them putting a bunch of probes on a starship and having them separate in martian orbit, landing at candidate sites. The combination of the 2 will lead to a lot of valuable data to decide where humans will land first. Around mars it's likely the satellites will be in a higher orbit, but there's no internet needing low latency there either, at least not at first. They could be a basis for a mars positioning system. If a lower orbit is used they could potentially use synthetic aperture radar to get high resolution scans of the surface. It's probable that many starships will already be waiting on the surface by the time humans make the trek out there. Presumably loaded with food, equipment parts etc... For how quickly the ships are fabricated we aren't looking at a scenario where ships are in short supply.

potato3732842 2y ago

During the second world war the British not so famously (it's not like it's something you brag about) spent a lot of money and effort building extremely heavy tanks or assault guns designed to help a spearhead a breach of the Siegfried line. They turned out to be mostly unnecessary due to a combination of factors that can be roughly summed up as "quantity has a quality all its own" and the projects were steadily cancelled as the war in Europe wound down. It's likely that some of these big unknown problems will similarly evaporate or prove to be easily solved once we actually do stuff like put humans in deep space ad on the moon for serious chunks of time.

thomascountz 2y ago

I think this quote sums up the monumental difficulties nicely: You can think of flying to Mars like one of those art films where the director has to shoot the movie in a single take. Even if no scene is especially challenging, the requirement that everything go right sequentially, with no way to pause or reshoot, means that even small risks become unacceptable in the aggregate. By now, a lot of individual problems needing to be solved for a Mars mission have sound solutions! But taken in aggregate, it's unbelievable to me that one could simply believe we're ready. We've done life support in LEO for decades, we can use Mars' nitrogen-rich atmosphere, we can pack a bunch of rockets with supplies! Yes we did and yes we could and yes we very well may! But, as the article makes clear, the engineering challenge ahead isn't in having all the puzzle pieces flipped right-side up, it's in putting the thing together and keeping it together during a wind storm.

foobarbecue 2y ago

"The closest thing humanity has built to a Mars-bound spacecraft is the International Space Station." Mariner, Viking, Odyssey, MRO, Maven, MEX, TGO, MER, Curiosity, Insight, Zhurong, Perseverance, Ingenuity all over there like HELLO!? But yeah, I know they meant to say "crewed" ... and the rest of this article seems accurate.