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Mars Now (nasa.gov)
229 points by 1970-01-01 on Dec 13, 2022 | hide | past | favorite | 175 comments

Way back in 2006, as a CS major with networking emphasis, I did a summer internship at NASA APL (Applied Physics Laboratory) My task was to modify Linux networking stack to simulate deep space communication packet loss and throttling. Then to implement something called Bundle protocol over UDP and run a lot of throughput simulations.

The idea was to maximize data throughput between Mars and Earth by routing data packets from the rovers to the orbiters because the orbiters circled every 90 minutes and the rovers had to wait hours for Mars to rotate to get line of sight with Earth. Also, some orbiters can send at higher throughput than others.

It was a fun project but way over my head at the time. I do remember walking into mission control a few times and ESPN was playing on the big screen. World cup was going on that summer.

This is neat but the mouse controls are maybe 5x too twitchy on my fairly standard Mac in Chrome. Google Earth's tuning is very usable in a way that this is not.

Seems to me like the problem is the pan rate doesn't decrease as you zoom in as you would expect. Panning is fine for me zoomed out, but way too fast zoomed in.

Same. Firefox on Linux.

+1 Chrome on Windows. I wonder if it's just designed for touch controls?

Probably, it works great on my iPhone.

So the "mobile first" paradigm still refuses to die?

Firefox on Android - same issue.

I hope we get that greenhouse on Mars sooner rather than later. Seems more important than Twitter.

Off-world crop production can benefit life here on the Homeworld. We are working on that with our ExoLab missions. Our 10th mission is currently on the ISS looking at legumes for protein and vitamins like thiamine. https://magnitude.io/exolab-10

No offense, but how? It just seems way more economical to grow plants in the environment they were evolved for.

Seems it would be useful to quantify what that environment specifically is, maybe find some ways to improve it such that the plants are hardier or have better yields.

Why do people think this is even possible? CO2 is heavy stuff. All it will do is just fall back to the surface. Maybe methane will be better or even better will be O3 ozone. But methane does not last. And I’m not sure how to get ozone in the planet.

Also, we hardly understand life on earth. Do we really think we can get life on mars for long periods of time?

Maybe they meant an actual greenhouse, not a greenhouse effect.

I was referring to the greenhouse that Elon Musk planned to launch to Mars that led him to found SpaceX.

yeah. I realized that after someone else posted the same. I was referring to another crazy idea: Nuke the CO2 ice caps for a greenhouse effect on the entire planet. [1]

[1] https://www.sciencealert.com/elon-musk-still-wants-to-drop-n...

Yes. Most people think it wouldn't work.

Gonna have to figure out how to deal with relativistic iron nuclei:


> relativistic iron nuclei

The Martian atmosphere is 1/166th the density of Earth's [1]. At the ISS's altitude, it's something like a trillionth.

[1] https://en.wikipedia.org/wiki/Atmosphere_of_Mars

The Martian atmosphere does not provide meaningful shielding against heavy ion radiation unless you're way down in the Hellas basin (where no one particularly wants to land). You reduce the flux by half compared to deep space just by having a big rock blocking half of the sky, but you'll still get all the cancer sooner than later.

A little napkin math says the columnar mass of the Martian atmosphere is 18 g/cm^2, versus 10g / cm^2 of aluminum shielding discussed in the paper. So being on the Martian surface would probably give you something like 1/10 (atmosphere + planetary mass + environment suit) the heavy ion radiation exposure of deep space. You'd need to be pretty deep underground most of the time (no windows, at least) to be safe for the duration of a reasonable visit. I'll pass!

The napkin math falls short a bit because the heavy ions that absorb in the atmosphere will create a shower of secondary radiation that reaches the surface. Similarly, heavy ions that hit the surface will create secondary radiation from rock. This factor is why partial shielding in a spacecraft can give the crew a bigger absorbed dose than having no shielding at all.

You're right, actually, that means even more exposure than I calculated since even the relativistic ions that are absorbed will still have potential biological effects via the secondary particles. Do you know how to calculate the flux from those?

This paper looks like a good starting point: https://www.sciencedirect.com/science/article/abs/pii/S22145...

Nobody is arguing radiation isn’t a problem on Mars. Just that heavy-ion bombardment per se isn’t something to be concerned with.

That is not true; the heavy ion component of galactic cosmic radiation in particular is the single biggest risk factor in going to Mars (other than the spacecraft breaking).

> galactic cosmic radiation in particular is the single biggest risk factor in going to Mars

Sorry, I was unclear. It’s absolutely an issue going to Mars. It isn’t front and centre on Mars.

It is, though. It's about half as bad on Mars (since the planet physically blocks half the sky) but it remains a showstopper. And trying to shield against it runs you into the problem of getting heavy construction equipment to Mars, plus you run afoul of rules against contamination that we're bound by international treaty to follow, including a ban on digging.

> rules against contamination that we're bound by international treaty to follow, including a ban on digging

Is this OST related? Or Mars specific?

It's the Outer Space Treaty as interpreted by COSPAR, which has introduced concepts (like Special Regions) that are unique to Mars. One Special Region is defined as anything more than 5m underground.

Lol - let’s have a Mars colony without digging.

Actually, there is : https://caseyhandmer.wordpress.com/2019/10/20/omg-space-is-f...

It is time we move away from the LNT (Linear No Threshold) radiation risk modeling. See https://en.wikipedia.org/wiki/Ramsar,_Iran#Radioactivity

The Martian atmosphere may not but the surface of the planet does, cutting half the yearly dose versus being in deep space. And I'm not sure I buy the argument that the atmosphere provides little protection. There's a lot of atmosphere there still, enough you can push down on it and rise into the sky if you have some carbon fiber blades moving at very high speeds. I'd think a iron nuclei would hit a lot of atoms on the way down.

> you'll still get all the cancer sooner than later.

Cancer risk from radiation is probabilistic. If you spend all day outdoors then you increase your lifetime risk of cancer by a significant degree, but it's not like you're definitely going to get cancer. Additionally, most habitation modules, at least early on, are planned to be buried in martian regolith.

Also the moon is worse than Mars in all respects with regard to this so you're effectively arguing that humans should never leave the orbit of Earth. I'm not a fan of that future.

(BTW, we deal with much higher radiation levels in hot cells in reactors here on Earth, and those even have windows into them. I'm sure we can work out something.)

You don't have to buy the argument; you can look up the scientific papers. Heavy ion radiation is hard to shield against and creates high energy secondary radiation when it hits air, metal, or rock. Moreover, there is strong evidence cancer risk from heavy ions is considerably greater than predicted by the absorbed dose model we use for other kinds of ionizing radiation. Search on "non targeted effects heavy ions" to read up on this; it's a fascinating topic. The upper error bar right now for a 1000 day Mars mission is upwards of 20% risk of radiation-induced death; most of this is from the heavy ion component of cosmic rays.

I'm not very knowledgeable, but couldn't we wrap the space suits in tinfoil or something?

This works for lower energy particles (like protons from the sun), but for heavy ions partial shielding makes the problem worse than not having shielding at all, the small number that hit the metal instead of passing through create a shower of damaging secondary radiation.

Effectively shielding people from cosmic rays requires either a thick atmosphere, a couple meters of soil, or really thick slabs of metal. The best solution on Mars might be to build a shelter inside a cave or lava tube, but then you run up afoul of international treaty obligations to not contaminate these sensitive environments.

The short answer to your question is "yes, but the foil has to be three feet thick."

I mostly agree with that but you don’t need to hand wave as much.

The atmosphere of mars is roughly equivalent too 2 inches of soil if the source is directly overhead and 3 inches at a 45 degree angle, but far more than that at low angles. Anything below the horizon is blocked by the surface of Mars, so you end up with well over 50% shielding from cosmic rays vs the trip to Mars. Being further from the sun is also beneficial.

You definitely want to live and work underground on Mars or at minimum below a large water tank, but even just landing in a valley can noticeably reduce radiation exposure as the mountains block portions of the sky so too do they block a portion of cosmic rays.

I think you have this backwards; GCR flux increases with distance from the sun.

For GCR, but not total radiation exposure. Cosmic rays are a combination of solar energetic particles and GCR.

Though this is dependent on how active the sun is: “If the instrument had been taking measurements on Mars during the comparable period of the solar-activity cycle about 11 years ago, it would probably have seen eight events in 300 sols, contributing an unknown but certainly significantly higher amount to the overall dose.” And of course if Mars was closer to the sun these numbers would be significantly higher. https://www.nasa.gov/jpl/msl/mars-rover-curiosity-pia17600.h...

I've been talking since the top of the thread about the heavy ion component of galactic cosmic radiation, not space radiation in general.

I realize. That line was simply pointing out that while being further from the sun is a net negative in terms of GCR it’s a net positive in terms of total radiation exposure.

Rather than speculation it'd be useful if there was more hard science on the subject, you know by actually doing long term experiments on life in space being exposed to these heavy ions.

You can find scientific papers on a lot of subjects where it's hard to get at objective fact arguing one way or another and it's hard to tell how factual they really are.

Also why would you quote the "upper error bar"? I'd like to know the size of that error bar and what the median is.

> The upper error bar right now for a 1000 day Mars mission is upwards of 20% risk of radiation-induced death; most of this is from the heavy ion component of cosmic rays.

This is just an argument that you need to bury things in regolith, at least early on, until we get better shielding designed for heavy ions.

Here's the specific citation:

Assuming 940 day mission, percent risk of radiation-induced death for a 40 year old woman is:

* mean: 8.8; 95% confidence [2.78, 21.0]

For a 40 year old man:

* mean: 6.49; 95% confidence [2.58, 13.6]

Source is "Cancer and circulatory disease risks for a human mission to Mars: Private mission considerations", Acta Astronautica, 2018.

Narrowing this uncertainty range requires long-duration human or animal experiments outside the magnetosphere.

It’s also dependent on the effectiveness of various cancer treatments as well as the specific location etc.

These figures aren't limited to cancer, they include the risk of (also poorly understood) heavy ion radiation induced cardiovascular disease.

Thanks for the raw data. That's a very wide range.

> in the Hellas basin (where no one particularly wants to land)

Why don't people want to land down there? Is it too rough a surface, more so than at higher elevation? Would it be feasible to land outside the basin and make your way down?

There's a great StackExchange answer on this. Basically, both the terrain and weather are bad:

"Sites of areologic interest are far apart, its seasonally induced micro-climate conditions are rough and pronounced due to somewhat larger surface atmospheric pressure, winds are stronger, dust storms longer lasting, it experiences higher seasonal and diurnal surface temperature variations, shorter days and exposure to sunlight during Southern hemisphere winters, and as a deep impact basin, terrain is fairly rugged, inclined, and often covered with deep pockets of sand.”


The thing is, if you intend to do something like establishing a completely self-sustaining population on Mars (one that could live indefinitely of the earth disappeared), then you need to have a presence in many many places on Mars, because you need access to numerous raw materials.

For a simple visitation mission, you can pick an easy place, sure (the other reply points out why this basin is not in fact that easy). But this does nothing to prove that long-term habitation of Mars is in any way possible.

Freeze peach always seems unimportant until you lose it.

Good thing that goes hand in hand with economic improvement, based on historical evidence, and make greenhouses on Mars more likely.

If our free speech rights depend on the whims of billionaire media owners we don't have those rights in any meaningful sense. I don't think that Twitter changing hands moved the needle one way or the other.

Twitter is just one, now fully exposed, symptom of a larger problem, which will be easier to deal with now that more people are watching.

It definitely moved the needle as you can see from the wailing and gnashing of teeth by a lot of the billionaire owned politicians, bureaucrats, institutions, and legacy media corporate "journalists".

It's funny how angrily and desperately they insist that nothing really changed and everything is a "nothing-burger", but they're gaslighting you as usual.

Speech and public opinion is still under the control of billionaires, and Musk is not likely to be particularly less greedy, self-serving, or egomaniacal as Murdoch or Soros or Bezos, but he is not in lock step with them. The enemy of my enemy is... quite possibly still my enemy, but it's beautiful to watch them fight one another. And if it can distract them from starting new wars or stealing more money and rights from people for just one minute, that's a wonderful bonus.

"Once social change begins, it cannot be reversed. You cannot un-educate the person who has learned to read. You cannoy humiliate the person who feels pride. You cannot oppress the person who is not afraid anymore." —Cesar Chavez

People have high hopes that Musk is some kind of principled arbiter but it's wishful thinking. https://www.cnn.com/2022/12/14/tech/elonjet-twitter-suspende...

The Twitter takeover solved a real, current problem. Those are always more important than future problems.

> a real, current problem. Those are always more important than future problems.

You mean like addressing climate change, vs spending trillions trying to terraform a planet to make it barely habitable.

I know it’s not my money so I don’t get a say[0], but I kind wish Musk had spent that $44 billion making a factory that makes shipping-crate sized Sabatier-process units to turn CO2 into methane.

Needed for Mars, useful for Earth.

[0] and, indeed, have used that argument against his critics when Musk was just a plucky upstart spending mere hundreds of millions on making the prototype that led to the Falcon

Maintaining free speech will allow people to discuss and shed light on actual—not heavily manufactured—issues like the climate change movement being used as a distraction while banks and corporations implement natural asset corporations. [1]

[1] https://unlimitedhangout.com/2021/11/investigative-reports/u...

At this point I think we just need to accept, that every issue of every severity is widely used by parties, who know how to benefit from it. It doesn't actually prove or disprove the issue (and its severity itself).

For example: climate change is heavily used by people who know how to gain power by fighting it. It doesn't disprove the issue itself.

All effective strategies includes natural forces, because it is very difficult to fight against them. So no wonder why climate change (as being a massive natural force) is used by people in power for their benefit.

> It doesn't actually prove or disprove the issue (and its severity itself).

It does when you consider that the very people who are promoting that severity are doing what I linked above behind the scenes and their own behavior hasn't changed at all (e.g., all of them flying private jets to Egypt for COP, having multiple pieces of real estate, etc).

The harsh truth is that the very people who are responsible for telling people to panic are, in fact, not panicked at all and are using fear as a smokescreen to take absolute control over the entire world (zero hyperbole in that statement). It's classic sleight of hand, just on a global scale.

Because many people in the West lack any spiritual grounding, they've latched on to climate change (think about the term alone; of course the climate changes—it always has) as a pseudo-religion and defend it to absolutely irrational ends. This is why anyone who even remotely questons it gets labeled as a heretic ("climate change denier"). You may as well be saying "you're denying my god" which explains the often-hysterical backlash you get.

Your inference that rich people using private planes means climate change is overblown is a non-sequitur. If your doctor was obese and told you that you should lose weight and exercise more, does that mean that their advice is wrong?

In my own life I know I consume way too much sugar. No doubt it is bad for my health, yet I do it. Does that have any bearing on the notion that consuming 1000+ calories a day of refined sugar is bad for me?

Secondly, you are creating a strawman argument. Show me the scientist who is saying what we need to do is to panic? What they are saying is we need to take corrective actions ASAP. Those two things aren't remotely the same.

Third, you make claims about people's motivations being tied to lacking spiritual grounding. That seems like a testable claim: I would bet there are tens of millions of self-described religious people who believe in AGW and that it is an urgent problem. In my own, US-centric experience, the main correlating factor is political identity, not religious identity.

> Your inference that rich people using private planes means climate change is overblown is a non-sequitur.

Not "rich people," people who are going to climate conferences whose primary purpose is to figure out how to lower carbon emissions and meet C02 goals. It's a perfectly logical conclusion.

> Secondly, you are creating a strawman argument. Show me the scientist who is saying what we need to do is to panic?

Scientists do not (precisely how I know the fervor is a lie), but there's plenty of "crisis" and "red alert" language which lead to people panicking (see: idiots blocking traffic or gluing their hands to art) [1].

> Third, you make claims about people's motivations being tied to lacking spiritual grounding.


[1] https://phys.org/news/2022-04-page-red-climate.html

> The harsh truth is that the very people who are responsible for telling people to panic are, in fact, not panicked at all...

True. Or, at a minimum, they aren't doing anything concrete that you would expect if they actually believed what they're saying.

> ... and are using fear as a smokescreen to take absolute control over the entire world (zero hyperbole in that statement).

Zero? Really? I'm calling baloney on your claim here.

> Zero? Really? I'm calling baloney on your claim here.

Yes. They're surprisingly overt about their end goals. I think the gullibility of "the masses" even surprises them. They want to flip the world economic system to be "stakeholder" based, meaning, they own everything (literally, down to the land itself) and you own nothing. It's neo-feudalism.

The whole climate change brew-ha-ha is simple psychological manipulation, i.e., "we'll tell you the sky is falling with our models, reinforce it via the media co's we control, and repeat it until you accept it as truth." People who are terrified will listen to anyone who appears to have an answer or is operating from a position of authority (the last 2-3 years being a beta test that was successful). It's just the Milgram Experiment/Agentic State thing on a massive scale.

These people believe they're the rightful rulers of this world and all other people are, for all intents and purposes: assets on Earth's balance sheet.

I can't help but think of two webcomics when I read your comments:

"they want to flip the economic system..." https://www.butajape.com/comic/conspiracies/

And "of course the climate changes--it always has" https://m.xkcd.com/1732/

What you fail to recognize, or refuse to recognize, is that global conspiracies to take over the world are completely unnecessary to explain everything you mention. Just pretend for a moment that human behavior really is warming the planet and, if continued, will have devastating effect. Some people would freak out. Some would not care because they'll be dead before they feel the impact. And some people would tell others what to do but hypocritically continue to act in their own self-interest.

The harsh truth is that conspiracies rarely pass Occam's Razor.

Flipping the economic system isn't a conspiracy theory, it's a stated, documented plan [1].

On the CO2 side, even your comic is incorrect (it has to draw dotted lines to force its "joke") as CO2 has been decreasing: https://www.statista.com/statistics/183943/us-carbon-dioxide... and with proper application of regulation, carbon capture [2], and nuclear energy, will continue to decline.

> Just pretend for a moment that human behavior really is warming the planet and, if continued, will have devastating effect.

I have. For a long time. The effects it's having (per scientists, not news outlets) are immediately manageable and if people quit being ignorant about energy policy (wasting money on windmills, solar panels, and batteries and instead invest in nuclear safety and redesigning regulation), can be outright solved and made a non-issue long before grandma melts in the backyard.


What you fail to recognize is that you've been programmed, intentionally, to dismiss anything you disagree with as a "conspiracy theory." A term that was coined by the CIA to discourage people from questioning the JFK assassination. [3]

[1] https://unlimitedhangout.com/2021/11/investigative-reports/u....

[2] https://carbonengineering.com/

[3] https://archive.org/details/CIADOC1035960/page/n1/mode/2up

> CO2 has been decreasing

You're looking at the wrong statistic, my friend. Climate is a global issue, so global emissions matter more than US emissions. Try this graph, from your same source: https://www.statista.com/statistics/276629/global-co2-emissi...

(Of course CO2 declined in 2020-2021 due to the pandemic shutdown. Unfortunately, 2023 global CO2 emissions will likely continue the prior growth trend.)

Your comment that the proper application of regulation, carbon capture, and nuclear energy would fuel declines is fine and I support all of the above. However, climate deniers and opportunists cherry-pick data and stall needed regulation in the name of politics and economics.

Carbon Engineering-type solutions and generalized R&D into massive climate capture is absolutely necessary, but has little to no business model behind it without a carbon tax or other market-driven incentive. Again, climate deniers lambaste government-funded climate R&D and free-market incentives (i.e., accurately pricing carbon) as either pork-barrel politics or unnecessary and broad overreach. I'm being kind, because people at the extremes use much more dire language.

Carbon Engineering is a fascinating case study and odd place to hang your hat. They are a startup, with 142 employees on LinkedIn and their flagship plant "is expected to capture one million tons of CO2 from the atmosphere annually when complete."[1] Humans emit approximately 35 billion metric tons of carbon annually, so it would take 35,000 Carbon Engineering plants in production to get us to carbon neutrality. And even then, our atmospheric CO2 is still 100 ppm higher than it was in 1960[2]. Who pays for building those plants? At best-case cost of $94/ton, who pays the $94M/year operating cost per plant, or $3.3 trillion per year?

Actually reversing the carbon impact requires us to massively reduce emissions and massively invest in carbon capture. We're not doing either.

Nuclear is a phenomenal technology, but a political and regulatory nightmare. Thankfully it's being re-thought, but that will take time - as will the process of building them. Significant additional nuclear power won't be connected to the grid for a minimum of 7 years, maybe 10. It's just not enough.

This is why "all of the above" is such an important concept. We need to invest in research, revise regulations, create market incentives, and use wind and solar that are available today to feed our growing need for power instead of building new coal and gas fired plants.

But there will never be the political will to do all of that when people delude themselves to believe carbon is declining (it's not), solutions will appear on their own (they won't), we aren't affecting the climate (we are), and the drive to shift to a lower carbon footprint is because a cabal of elites want to take over the world (they probably are, but that's always been the case and that doesn't mean climate change isn't real).

[1] https://carbonengineering.com/ [2] https://www.climate.gov/news-features/understanding-climate/... [3] https://en.wikipedia.org/wiki/Carbon_Engineering#Pilot_plant...

There is no evidence there is more free speech on Twitter after the Elon takeover. It's just different people being banned and for more arbitrary reasons.

I could understand saying something like the totality of the evidence doesn't support the conclusion that there is more free speech after Elon's takeover. So that is probably what you mean. What you actually said though is factually inaccurate.

There is evidence both for and against more free speech on Twitter. If someone can't admit that, chances are they are plagued with cognitive dissonance and highly partisan in their reasoning. For example, there is evidence that Twitter has granted amnesty to accounts that were previously censored and according to stated motivations this was done for the sake of freedom of speech.

I happen to suspect that you are right and that currently some rulings are made with input outside the policy team and that this is currently happening more frequently than it used to. One thing that convinces me of this is that I frequently see people reaching out to Elon Musk directly and reporting that they have been censored in some way or the other. Then these cases seem to be resolved, with the other person praising him for ending the censoring of their political thoughts, which implies that he intervened in a policy decision.

However, I'm not sure I could call this proof that banning decisions are made more arbitrarily than before since these are blacklist removing interventions rather than bans.

So basically, when you claim that is now more arbitrary than it was before, that comes across to me more as your own speculation than anything definitive. We don't have proof of that. In sharp contrast, anyone who claims that the previous ownership did make arbitrary decisions does have proof. It is now a matter of public record that in some high profile cases (I happen to agree with some of them, but that is beside the point) Twitter did make arbitrary decisions rather than policy rooted decisions. In fact they did this often enough in decisions that weren't as high profile that there was a category label in the moderation reason, being called a one off.

It seems the current Twitter wants to be much more transparent than the former. So it might be that at some point in the future we will be able to see the moderation metrics: if we could, then we could answer your implication with with actual data. Filter by moderation justification field and get a count both positive and negative and we would have a much better sense of whether decisions were being made arbitrarily.

Do you think your comment is still good after this https://news.ycombinator.com/item?id=3398387?

My comment was not as serious as yours. I would say that I don't really know why Alex Jones is still banned from Twitter. It's unclear what the guidelines are. And in my view the "poll" to get Trump back showed there is no policy.

But as you said it's early days with not much evidence. Perhaps it will work itself out.

I think it is way too early to make that call.

I guess now we have enough data? https://news.ycombinator.com/item?id=33983878

Fair point, but as of now I think it's a valid statement.

At least he managed to get red of CP.

Umm.. no it did not.

In the grand scheme of things, Twitter is noise.

> solved a real, current problem

Can you tell me what that problem was?

Too many people making fun of Elon, apparently.

Couldn't dog whistle loud enough on Twitter

Oh you could loudly dog whistle on Twitter pre-Elon, but only one side was allowed to. Now that Elon's equalizing the playing field, both sides can dog whistle. And you know the saying, if all you've known is privilege, equality feels like oppression.

What Elon does with his time and money is his own business. What are you doing to help humanity get to Mars beyond scolding the person who is arguably the greatest single contributer to humans in space of the past 20 years?

I don't want humanity on Mars. On Earth is bad enough.

But we won't be going to Mars, help or no. Starship and Superheavy (Can and Kicker, by my lights) are woefully inadequate to the task.

you may want to consider why you're taking OPs comment about Elon Musk personally.

I know why I'm taking it personally. Some people work hard to make the world a better place, and some people sit on the sidelines making comments about working harder.

It's disappointing to see someone go from inspiring to ... uninspiring.

Can't get the fascination with this desert? It's like post apocalyptic Earth.

If you discovered a post apocalyptic Earth somewhere in the solar system, you wouldn't have any interest in checking it out? It's ok to say no to this, but just be aware that most people consider "because it's there" to be a legitimate and relatable answer to your question.

Venus is the post-apocalyptic Earth you're looking for.

Just want to clarify, in case someone reads this and thinks "like in the movies, where after the apocalypse it's barren and radioactive and very hot or cold and you can't survive outside unless you're wearing a suit". That's not what it's like on Venus.

The atmosphere is made mostly of CO2. At the surface, it has a pressure of 93 times that of Earth, and temperature of 464 °C / 867 °F. This is sufficiently hot and pressurized that the atmosphere is neither a gas nor a liquid, it's a supercritical fluid. Wikipedia says that we use supercritical CO2 industrially because of how good it is at dissolving things.

The record survival time for a stationary probe on the surface of Venus is 127 minutes.




Venus is also pretty cozy if you're willing to bring a blimp. At 52 kilometers, the temperature is 27 C and pressure is about half of Earth sea level. If it weren't for the sulfuric acid clouds, you could sit on a platform outside in just your shorts and an oxygen mask. Not many other places in the solar system can offer that!

Venus became that way because of its' oceans and no counterbalancing moon.

Nope; it's because it's closer to the Sun (whose luminosity is increasing over time, btw, so Venus got cooked more and more until it got into a critical greenhouse effect).

Venus is also strange for having a retrograde (and very slow) rotation relative to other Solar System planets due to a mix of being close enough to be tidally locked to the Sun and its (now extremely thick) atmosphere creating strong thermal tides that affect its rotation. It used to be thought (and I thought this) that its retrograde rotation was due to impacts in its early history. But, in any case, having moons is unrelated.

It lost (most of) its rotation because it has no moon, nothing to counter solar tides.

Because it lost its rotation, it lost its magnetic field. Because it lost its magnetic field, it lost its hydrogen.

Mars lost its hydrogen the same way, because its core froze enough to kill its magnetic field. There is more than one way to go.

Venus is in a bad way.

Yup. Oceans. Ask Anton Petrov. https://www.youtube.com/watch?v=Y_fiFzTceZc

> most people consider "because it's there" to be a legitimate and relatable answer to your question

I don't think hackers, explorers and founders have ever been most people.

No, but most people think hacking, exploring, and founding stuff is cool even if they don't do it themselves.

What data do you have that demonstrates what "most" people think is "cool" in this respect?

You are correct: historically hackers, explorers and founders are significantly more likely to respect "because I can" as a reason for doing something than the average person.

I think "because it's there" is the more respectable subset of "because I can", covering stuff like climbing Mount Everest and venturing to the South Pole. "because I can" for me often implies something like asserting power over other people or just generally being an asshole.

Short answer: It is in space and relatively easier to get to than other planets in the system. It is a gateway to becoming space-faring civilization.

The second part of this answer is a non-sequitur. Why Mars in particular? The technology needed to get there doesn't carry over to any other destinations except the Moon and Venus, and it's much easier to build next-generation rockets on Earth. Why not just skip Mars and go straight to step 2?

You need resources to build with. Venus isn't an option because you can't get resources from it. (If there's two things you need, it's energy, and physical materials.) The Moon is certainly an option, but while Mars is a desert, the moon is volcanic rock and never had active geology that concentrates metals. Additionally while Mars has an atmosphere of sorts, the Moon has none which means anything mounted on the surface of the moon is in an equivalent environment to being in deep space. This means there's zero protection (besides the planetary body itself) from radiation and micrometeorites (and bigger meteorites). They rain down constantly on the moon slowly carving divots into whatever you build things out of or punching holes in them.

Also I disagree that the technology to get to Mars or the Moon is inapplicable to elsewhere in the solar system. And most of the other options are generally worse than Mars for one reason or another. I'd like to hear what you think "Step 2" actually is.

We have resources at home!

We do! And for a long while most of the resources will come from Earth. However you can't keep doing that forever as the costs will grow to an unsustainable level.

If you could magic up a civilization on Mars today, it'd exponentially cheaper to launch materials from Mars to elsewhere in the solar system than to launch those same materials from Earth. Similarly it'd be cheaper to dig those materials out of the ground for use on Mars than it would be for them to be used directly on Mars.

Counterintuitively, it's cheaper to launch materials from Mars to Earth's Moon than it is to launch them from Earth's surface to the Moon.

One note on the "exponentiality" in the other comment. Getting from Earth's surface to the moon (without staging) requires a rocket that is approximately 99% fuel by mass (calculated using rocket equation and engine performance of a high quality engine). That leaves you with very little margin for building a rocket's structure which means it needs to be built extremely carefully with little room for error. Also in order to get reasonable payloads, you need to make rockets of tremendous sizes in order to get reasonably sized payloads to locations.

On the other hand a rocket that flies from Mars surface too Earth's moon only needs to be 90% fuel which is a lot easier to do with modern materials. This also means that you can carry significantly more payload as your total mass.

With some napkin math, this allows you to launch, with the same rocket, from the surface of Mars to Earth's moon a payload 10 times bigger than if you launched it from Earth. The penalty you pay getting stuff out of Earth's gravity well is just simply huge.

> The technology needed to get there doesn't carry over to any other destinations except the Moon and Venus.

The technology for living there, and some of the technology for going places, does. Would you really want to try to go to Epsilon Eridani without going to Mars first?

> it's much easier to build next-generation rockets on Earth

Ultimately probably not; Earth's gravity well is too deep. Mars is, AFAIK, the only place we could conceivably build a space elevator with current materials technology, so if we assume interstellar rockets will need to be built with materials from both asteroids and planets then Mars orbit is likely the best place for that.

>Mars is, AFAIK, the only place we could conceivably build a space elevator with current materials technology

That's not true: the Moon would be much easier.

But if you're just comparing Mars to Earth, then definitely yes. Building a space elevator on Earth is sci-fi for now. I'm not sure about Mars, but on Moon it would be rather easy actually, since not only is the gravity 1/2 of Mars', but there's no pesky atmosphere.

> the Moon would be much easier

Really? The moon's gravity is 1/2 or 1/3 that of Mars, but its angular velocity is about 1/27th.

It's not just the technology to get there we need. We need the technology to live there.

Absolutely true, but my point is that there's no destination beyond Mars reachable with the spaceships we build to get there. So I don't get how it's some sort of gateway rather than a detour / dead end.

The good news is we don't have anything to get to Mars with, either. SpaceX cans are comically inadequate.

> Earthers get to walk outside into the light, breathe pure air, look up at a blue sky, and see something that gives them hope. And what do they do? They look past that light, past that blue sky. They see the stars, and they think, 'Mine.'

(from The Expanse)

This is a great quote from a series I love, but I think it’s important to consider other angles.

Earth, metaphorically speaking, is humanity’s “cave”. A very nice and comfortable cave of course, the possibility space for the development of our species is bounded by it. It’s in our best interest to develop the ability to venture beyond the cave for increasingly longer periods and eventually become able to live outside of it indefinitely.

With this in mind, the moon is too close and convenient for long term self sufficiency to develop. Mars on the other hand is only reasonably accessible once every couple of years or so, which forces the issue of self-sufficiency right out of the gate. The first few decades of human presence there will be focused almost exclusively on self-sufficiency. This is important, because that means it has a far better chance of continuing to exist if/when political will for it wanes.

The upper layers of the Venetian atmosphere may seem attractive at first glance but it has several impracticalities, namely having to stay permanently aloft and total inaccessibility of the resources on and below Venus’ surface.

Will some take part in efforts to move beyond Earth’s surface with greed as a driving factor? Undoubtedly, but I don’t think it’s a valid reason to not do it.

Oye sesata unte beratna; kewe tolowda?

So? That's what got us out of the caves in the first place.

The first words spoken on Mars should be, "Cool. Now, how far is Jupiter from here?"

We've known since Pioneer 11 that Jupiter is a no-go for the type of spaceships that can get to Mars. Too much radiation on the way, and too much around Jupiter. Mars is the end of the line until we can build spacecraft in the 10,000 ton range.

Why? (Not saying you're wrong, just... explain/substantiate your claim.)

The general problem is cumulative exposure to cosmic rays on long-duration flights. It's not clear if even a Mars mission has acceptable risk, and flights past Mars mean everyone gets a very high risk of cancer and radiation-induced cardiovascular disease.

To shield against the high energy component of cosmic rays, you need to wrap the crew compartment in something like a few meters of polyethylene or water. This is far heavier than anything we could launch today, but would work on something like a nuclear pulse rocket (that has a minimum weight requirement!)

There's an additional problem around Jupiter, which is what Pioneer 11 discovered. The strong magnetic field causes lethal radiation levels at the inner moons. Again you can solve this by wrapping yourself in crazy amounts of water or plastic, but it's far beyond our capability now.

I logged in to un-down-vote you.

Going to Mars is a legitimate goal.

But i would also like to see a make-the-Sahara-green-(ish) program.

Why not a Neom-but-in-a-viable-way program.

ALso, an even bigger debate is Appolo-mission-to-Mars vs 10-other-unmanned-programs-for-the-Solar system.

Intentionally radically altering the climate of large areas like the Sahara seems very dangerous in a way that nothing that could be done on other celestial bodies could ever be. Not that it shouldn’t be considered, but I think it calls for a far greater degree of caution than e.g. experiments to bring life to small domed areas of the surface of Mars.

If you have the technology to make small domed oases, make them in the Sahara (or Antarctic, or wherever). No need to change the climate, and you save the cost of a Mars trip.

I upvoted you because it's a fair question, but I would argue it is easier to criticize than to offer solutions.

What other solar system destination would you propose instead? It's not like we have a lot of convenient alternatives to choose from.

I'd rather visit Mars than Venus, that's for sure.

Venus is great! Come visit! Stay at the beautiful Hyatt Floating Resort! It's got everything you want - Earth temperature and pressure, lots of solar energy to power your every whim, beautiful sunrises and sunsets.

Just don't visit the surface. It's really, really nasty down there.

We can visit everything for much less than the price of Mars if we drop the requirement to send people. There's cool stuff in the solar system and the future where you can flip between live feeds from every moon is much more fun than watching space dads sit in a radiation shelter on Mars for 17 months.

There are asteroids in near-Earth orbits. There was a startup some years back hoping to exploit some of them.

To be fair plenty of Earthlings say the same about their own planet. I for one am glad enough people do not share your opinion, which is completely valid, so that we can do the adventurous and exciting things that make life wonderful.

A post-apocalyptic Earth would still be much more inhabitable than Mars ever will be. Wildlife flourished in the Chernobyl exclusion zone.

It's an entire planet. Full of resources, land, opportunity for the entire human race if we could only get there and tame it. Surely everone can agree that it's a noble goal.

Without the desire to explore and expand there would be no America. If the Spanish and Portuguese would have waited to solve all of humanity’s problems first and then set out to explore new worlds the world would be a different place today. Same with space exploration. It is in our dna as the most advanced life forms to go out there. It is also a duty to all life on this earth to expand beyond. Finding even a hint of former life on mars means life is a rule not an exception in the universe. Being able to colonise it means we can outsource all our destructive resource gathering to mars. Or even better we can live on it. Doing so would mean trade with earth and as a result development on a scale never seen before.

> Without the desire to explore and expand there would be no America. If the Spanish and Portuguese would have waited to solve all of humanity’s problems first and then set out to explore new worlds the world would be a different place today.

Of all the examples you could have picked, you picked the one that was most explicitly not about desire for exploration. Europeans were not exploring the world for exploration's sake; they were stridently motivated by the promise of loot. The Spanish in particular explored the New World primarily to find new cities of gold to plunder, destroy, and loot, as was done to the Aztecs and Incas, with these entradas funded by people hoping for a share of the loot (unfortunately for them, there was nothing else on the scale of the Aztec or Inca Empires). Later, other countries sought less to actively loot the place but instead monopolize control over raw resources (beaver pelts being key in North America).

Better examples would have been, say, the Polynesian migrations that settled isolated islands in the Pacific Ocean, which the navigators would have had no reason to believe even existed.

The Americas and Africa would probably like to have a word about the legacy of Spain and Portugal's decision to "explore new worlds"...

Unfortunately the only thing to motivate most people is greed. I am aware of the legacy, but the way to sell this is by highlighting the profit that can come out of it. And fortunately there is nothing to kill on mars in the process. It’s a win win.


The ride home is free because the vehicles need to come back anyway to carry more people.

And not within our lifetimes will we be in a situation where people stop being the citizens of the country on Earth they are from.

> And not within our lifetimes will we be in a situation where people stop being the citizens of the country on Earth they are from.

Sounds like you aren't familiar with maritime law. Slavery is still a common practice on this planet, due to a lack of jurisdiction.


The vehicles have to come back, but the people have to eat and breathe on the way. And right now, I’m more than a little worried he’s heading the same way as the French royal family, even if "Qu'ils mangent de la brioche" predates Marie Antoinette.

I'm not sure where you see any indication that he doesn't care about people. If anything he seems to care quite a lot about people. Most of the reason for what he's doing is based on the reasoning of caring for people. You may not agree with him, but that's one of the driving things that's been consistent his whole life.

"Not caring" is not where I was going with that. It's the lack of alignment with normal people that makes me think of "let them eat cake" — it's very easy to be blind to someone else's economic realities with a mere x2 change in income, let alone when you're so rich your debt is the bank's problem if you mess up.

That said, there also seems to have been a set of significant personality shifts in the last 12 months, starting with Twitter being "yeah, I can afford it *shrug*" and him not even doing due diligence (he used to be cautious and signal risk of e.g. rockets exploding), to trying to back out of the purchase and saying the bosses were defrauding advertisers, to saying the purchase is a perfect opportunity for an "everything app" and comedy was ok now, to complaining about the advertisers who started leaving right after he let anyone blue tick themselves and some jokers got a blue tick and names suspiciously close to advertisers and memed away in various high-profile brand damaging satirical retorts against them.

I don't know if that's a mid-life crisis, side effects of prescription medication, experimentation with nootropics, recreational drugs, or something else, but he doesn't seem stable right now.

The Cans don't have to come back. It is overwhelmingly cheaper to leave them there and build more. (Scrap value of a Can on Earth is somewhere <$50k. On Mars, probably rather more.)

You might gather up the Raptor engines and ship them home (with their bells cut off). It is the only export from Mars that could conceivably be worth the bother, and then only if you had a Can returning for other reasons.

While I in no way disagree, I would like to note that some of the bad activities attributed to foreigners in Africa, have been practiced for millennia by the locals, and the World over.

> If the Spanish and Portuguese would have waited to solve all of humanity’s problems first and then set out to explore new worlds the world would be a different place today

I mean... yeah it probably would've been a lot better. They weren't the ones who explored the Americas. It was the people we now call Native Americans

If the Spanish and Portuguese had instead solved AT LEAST their own problems of constant famines and the inefficiencies and brutality of monarchies, they probably would've been a much kinder people...

People like to act like hierarchy is just an inevitable result of increasingly complex societies but there is no archeological or anthropological evidence to support this myth. There's fascistic hunter gatherer groups and the Americas themselves had examples of very large complex and extremely egalitarian societies. Like Teotihuacan which was nearly as large as Rome. After a brief fling with total authoritarianism the people had a revolution and ended up creating one of the first examples of public housing we have evidence of as well as dramatically increasing the average standard of living of everyone

Yeah I think the world definitely be a better place if they waited to solve their problems actually

This logic applies just as much to the Moon, but no one seems to be lining up to board lunar colony ships.

FWIW, I think we should aim for the moon before mars. Things will go wrong, the moon is close enough to mount a rescue if that problem is “the food is all gone”, whereas Mars… the gap between launch windows is long enough for things to go from “fine” to “everyone’s starved to death, including the ones who turned to cannibalism to survive”.

Then there’s the practicalities: while the moon has long days and nights, there’s no global dust storms, and we can send power from the light side to the dark side with a simple wire (the lunar regolith and the vacuum are both insulators, there’s nothing alive or tectonic to mess with one just draped on the surface, only impacts). The Martian atmosphere is so thin it’s only useful for aerobraking and drones, not breathing, and the lack of atmosphere on the moon means non-rocket-based launchers are much easier, which in turn makes the long-term economics easier (though still terrible with current tech).

There are no lunar colony ships.

There are just as many lunar colony ships as Mars colony ships.

Which tons of people signed up for a yearlong simulation of run by NASA. Granted, I bet a lot would drop out if presented with the actual prospect of spending a year in a bubble with 5 others.

Mars is easier to send material to; gravity and rotation are also better there.

I'd prefer our most brilliant technologists tap into the desire to explore and expand the domain of robotics. Once I own a robot that can reliably clean every surface of my bathroom without my intervention, maybe then Mars might sound a bit more interesting.

But, hey, that's just me.

> Without the desire to explore and expand there would be no America.


Is that good or bad?

>Without the desire to explore and expand there would be no America.

Please don't act like Europeans getting lost trying to find a shortcut to India was a good thing.

After researching this a bit it's mostly a money and reputation laundering scheme for the elite classes that millions of upper middle class westerners buy into to smokescreen what's wasted on war and geopolitical efforts to protect various western family dynasties hold on power.

Even though it's a future that is grotesquely unfeasible and unwanted for anyone besides the richest 100 people on earth as as ultra decadent projects while 95% of the population on earth lives in societies on their way to collapse from resource depletion and rising inequality.

This is a shockingly cynical and reductive take on Mars exploration. The enthusiasm for human exploration of the solar system is earnest and valid, and I assure you, not a cog in an international conspiracy. One doesn't have to choose between space exploration and addressing resource depletion/inequality. You can care about both.

I was a huge sci fi and science nerd 10 years ago and still am, and honestly i would love to go back and care less about how the world works, but to me the very real fascination with "actual scientists" and "actual science" has been overshadowed by the siphoning, the false promises and the cooking of statistics that happens while everyones tax dollars get channeled into a fog somewhere between "external enemies" and technooptimist drivel.

The fact is that we could use our money on something real, something tangible like saving earth instead of war machines and false promises while the gini coeffecient goes crazy and public education fails.

And i mean this is not just a perspective i've got from researching economics, but from having lots of family in academic science - i've seen how much is about grant money, towing the line and about furthering some state or corporate cause sadly.

The US military budget is ~3.5% of GDP. It makes up about 10% of all government spending. 90% of your tax money does not go to war machines.

The DoE budget is largely military in nature, too. Be sure to count the spooks' portion, as well.

Yes, we could explore the solar system much more quickly and much more cheaply, if we simply leave out the humans.

This has been explained repeatedly for decades.

There will be more humans on Mars in 100 years, if we skip sending the humans now and develop the technology to automate process first.

maybe someone can find Weinberg’s detailed explanation for others to read.


>There will be more humans on Mars in 100 years, if we skip sending the humans now and develop the technology to automate process first.

We can't do that anytime soon. We can't even reliably automate most manual labor jobs right now. We can do some neat stuff with robots, but we always need humans supervising them and ready to step in and reset things because the reliability is poor.

>...millions of upper middle class westerners buy into to smokescreen what's wasted on war and geopolitical efforts to protect various western family dynasties hold on power.

All the current active conflicts and threats of armed conflict are being caused by easterners, not westerners. You're about 20 years out-of-date with your complaint of warmongering by westerners.

Humans living for more than months at a time in space or on another planet is a fantasy. The attempts will kill the participants.

That is for machines or post-human life, designed for the purpose, to do, if it is even possible. The answer to "Where is everybody?" is likely to be "They're home" having learned that trying to leave is deadly.

Staying home stops being viable in approximately 500m years, which is less than 25% of life on earth. A majority of the time life can survive on this planet is behind us.

We’ve had 4.2bn years to figure out how to get off this rock. We’ve only got 500m left. In that time, life has printed exactly one golden ticket: humans. Staying here is deadly. The mentality that life on earth will be just fine dooms this planet to complete extinction.

We will be extinct long before then. Our successors, if we survive long enough, won't need planets, and will not even bother. Everything of enduring value is out in the Kuiper Belt. Cold, most importantly.

Those days are spread out over the course of over a few trips over nearly a decade.

Nowhere near to the amount of time you'd log on a trip to Mars and back.

The radiation flux in low earth orbit is also much milder, about 1/4 what you would be exposed to en route to Mars.

You don't think you could get to Mars and back in 520 days? Why not?

You could, at some cost to the health of astronauts. They won't die, right away, anyway. They will lose a lot of bone density, at a minimum. The other effects, like pooling of various bodily fluids, etc. will become both tiresome and more dangerous the longer they go on. They will get a lot of radiation. On ISS astronauts work out 2.5 hours per Earth day to control health problems.

Training enough astronauts for frequent missions will be extremely difficult, maybe infeasible. Colonizing Mars is a fantasy.

If anyone's wondering, looks like it's running ThreeJS! (you can tell by typing `THREE` in the console)

I love three.js, it's great for making high performance webgl that even run well on mobile.

I've long been curious: it looks like we haven't dropped any landers directly on the icy poles. Those seem like they would be a treasure trove of data- scoop up and melt ice, then filtersample the liquid.

I'm seeing outdated Perseverance data as if it hasn't landed yet, and no data on orbiters.

Wonder if the stars are accurate. The Sun is missing

That's not the only thing that's missing. Where's the Mars Reconnaissance Orbiter?

At least kind of related:

I'm worried that NASA will mess up their livestream of the Artemis 3 mission to the moon, just like they did with the Artemis 1. Compared to what we've been getting used to with SpaceX, it just wasn't that great.

Did SpaceX livestream the entire trip around the moon in real time?

(Well, NASA didn't do that. Most of the time it was an animation. When they did have a camera feed the production quality was very uneven.)

Have SpaceX livestreams set high expectations?

Look, I want NASA to look good, but I'm worried that they are treating the streaming as an afterthought.

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