The Shape of a Mars Mission

We've had a spacecraft in orbit around Earth for a quarter century with many astronauts having years of experience up there, including long duration stays of up to about a year. The idea that we can't do space with duration is silly.

The large rocket adddresses basically all the problems.

Time between resupply? Well, you can just take a bunch of resupply missions with you. Most stuff is packed ahead of time, except fresh veggies and fruits, but deep freezers can keep the nutritional value of those nearly as well as being fresh.

Redundancy/reliability? Bring the spare pool with you instead of keeping it on the surface for resupply flights. Bring two different systems.

Long duration life support? Enough mass allows you to avoid it all together if you like. This still has not sunk in to most of the fairly educated people who opine on this topic. Simple life support systems are VERY reliable, and the advantage of advanced life support systems is they reduce mass. If you don’t need the mass reduction, you don’t need the advanced life support.

Far from medical care? Small crew sizes are a mass constraint. More mass means you can afford large crews with dedicated medical personnel. And the equipment to go allow with it.

Also applies to radiation shielding (mass) and even partial gravity (centrifugal gravity is well known as a replacement but for some inexplicable reason is avoided… and yea, even short arm centrifuge is useful and could be used on the surface… the disorienting effects are actually manageable, and while in space, a tether can be used to enable long arm centrifugal gravity with little Coriolis effect).

Transit times can also be reduced significantly with refueling. 80-120 day transits are feasible, not just the most efficient 150-210 day transits for long stay. The surface of Mars also has significant radiation shielding in spite of the thin atmosphere. The Mars rover Curiosity measures the same radiation equivalent on Mars’s surface as on ISS today. Mars rover Perseverance also demonstrated production of unlimited oxygen from the Martian CO2 atmosphere using electricity. Regolith could also be used to enhance radiation shielding. This is before discussing water mining (and even that can be done without touching regolith, just the air using the WAVAR technique… useful for crew consumption although this method doesn’t scale up to producing enough for propellant very well).

There is no a single hazard or obstacle to a Mars mission that isn’t at least partially mitigated by having a lot more mass capability, ie a big and cheap reusable rocket (capable of landing on Mars and aerobraking).

We send spacecraft to deep space for decades on end, not just months. Oh, you meant CREWED spacecraft…

We are in fact far more ready for sending crewed missions to Mars than we were to sending crewed missions to the Moon when JFK made his Moon speech. We had only barely launched an astronaut on a suborbital flight at that time! And yet 7 years later…

I'm sure this question has been addressed already, but why not try a 1-year moon base first? With a hot standby ready to either rescue them or drop a brand new habitat.

Not to mention launching to Mars from the moon is easier (in some respects, not all).

A big rocket is probably the biggest obvious hurdle. What are other people doing to get us to mars that is better than musk's approach?

> 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.

Just to play devil's advocate, Isn't he getting the ball rolling? Put aside his unrealistic timelines, at least he's trying to solve the rocketry part of the equation. I feel like this extreme hatred is unwarranted.

It doesn't make sense to send humans except many humans want to go. Those humans are working on the project to go to Mars, not send robots to Mars. We can do both of course.

I would like people to start a civilization on Mars. I would like to go to Mars. I will pay for the privilege to do so or see it happen for othera. Maybe it will. There are many people like me.

I think people are more enthusiastic about robots than justifiable, because they see things like the Atlas robot and imagine that's the future. In reality the first man on Mars will likely discover far more in a week than we have in more than 50 years of probes, or in all probability would in 50 more.

The fundamental problem is that moving parts break. This results in things like rovers being exceptionally conservative in both their design and behavior, out of necessity. For instance Curiosity's drill can only drill to about 6cm, and even then it broke after 7 limited activations, which then took a team of scientists 2 years to come up with a partially effective workaround. A guy on the scene could have fixed it a few minutes, or done just as effective 'drilling' himself with a spoon. We're literally not even scratching the surface of what Mars has to offer.

Another issue is in mobility. That involves lots of moving parts. So Curiosity tends to move around at about 0.018 mph (0.03 km/h) meaning at its average speed it'd take about 2.5 days to travel a mile. But of course that's extremely risky since you really need to make sure you don't bump into a pebble or head into a low value area. So you want human feedback on a ~40 minute round trip total latency on a low bandwidth connection - while accounting for normal working hours on Earth. So in practice Curiosity has traveled a total of just a bit more than 1 mile per year. And as might be expected its tires have also, broken. So it's contemporary travel time would be even worse.

Imagine trying to dig into all the secrets of Earth by traveling around at 1 mile per year, and once every few years (on average) being able to drill hopefully up to 6cm. And all of these things btw are bleeding edge relative to the past. The issue of moving parts break is just an unsolvable issue for now and for anytime in the foreseeable future.

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Beyond all of this, manned spaceflight is inspiring, extremely inspiring. Putting a man on the Moon inspired an entire generation to science and achievement. The same will be true with the first man on Mars. NASA tried to tap into this with their helicopter drone on Mars but people just don't really care about rovers, drones, and probes. It'd be nice to live in a world where kids don't aspire to be friggin streamers when they grow up.

We should never have sent humans to Antarctica. We should have relied on binoculars from ships and maybe some blimps with cameras, right? I mean, what can a human possibly accomplish that a machine can't.

Also, we didn't "send" them, the early explorers and bases were done by people who wanted to go and do research there. We have lots of people who want to go to Mars to do research or who want very much to benefit from the research humans can do better on Mars than current robots.

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.

Humans are extraordinary machines.

We are self-healing, regenerating, low-power, versatile, autonomous, and most of us have a pretty decent array of sensors built-in, along with some communications equipment that's capable of interpreting the signals from our sensors and transmitting that information to other humans in a remarkable variety of ways. All of these are approximate and relative of course, if someone replies with e.g., "but actually we're not as low power as...", it will be easy to ignore.

Specialized machines can do things humans can't, of course. No single human could have survived as long in the Martian environment as any of the rovers have.

But nobody has yet designed a machine that can do all the things humans can do.

Take the single problem of mobility: many very smart engineers have worked together to develop a set of wheels that can usually move the rovers around their environment without getting stuck or damaged, or at least have a chance of getting unstuck. A human that hasn't climbed a set of stairs in a decade can still outpace the rovers, and do so over more varied terrain, and with less chance of getting stuck.

So, yes, from an engineering point of view, building new robots that can do things and shipping them to Mars to do those things presents a lot of very interesting technical challenges to solve. It's all endless puzzles and little unsung feats of science and engineering -- assuming there is a country left with both the will and the resources and the talent to pursue such things.

But from a human exploration perspective -- our instinctive drive, or compulsion, or whatever it is, that has spread our species across the entire planet -- no machine will ever quite satisfy the desire to have that experience with the sensors we were born with.

My enthusiasm for a human mission to Mars has waned quite a bit in the last few years, largely owing to its most vocal advocate. Still, all the same, I think we should acknowledge that robots are poor substitutes for geologists.

In the spirit of xkcd 1232[1]...

What's the timeline on "exhausting all the science collection abilities of robots?" Ten years? Fifteen? There are a lot of potential future robot abilities...

[1] https://xkcd.com/1232/

Yes, well, maybe logically speaking that would be true. Practically speaking hardly anyone blinks an eye when 'society' daily sends young (mostly) men into harm's way whether that be by employing them in known dangerous professions such as logging (etc.) or by sending them to war. According to the Geneva Declaration on Armed Violence and Development, more than 526,000 people die each year because of the violence associated with armed conflict and large- and small-scale criminality [1] while the world just keeps on turning. Nobody would even blink an eye if that number changed to 525.000 per year by putting dangerous criminals behind bars and keeping them there or by eradicating some terrorist group somewhere nor would they loose sleep if it changed to 527.000 per year after some conflict somewhere flared up again. Life is not as precious as it is often thought to be by most of us here on this site. Seen in that light it makes a lot of sense to choose 1000 volunteers out of the millions who would show up if asked to go on a mission to Mars, success not at all guaranteed and quite likely to be a one-way trip for the foreseeable future. Mars has been explored by a multitude of probes and rovers so sending the next one, no matter how advanced, will not cause much of a stir. Sending 1000 people to Mars with the intent of establishing an outpost will 'rock the world'. If successful (which is not at all a given) it would be one of the greatest achievements of our species while a successful robot mission would just be another tick on the list.

[1] https://databank.worldbank.org/metadataglossary/world-develo...

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?

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!

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.

Unfortunately, in spite of a lot of good material in it, it’s also deeply flawed.

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.

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

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.

Water is a big one. Missions to Mars will be carrying tons of it, and it's an absolutely excellent radiation shield.

> 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.

> I'd sign up for a Mars mission in a heartbeat, even if there was a 70% chance of success.

I am pretty sure that your confident self would think a few times before signing the NASA paperwork with this number.

It wasn't about pushing boundaries, it was about beating the USSR.

“ We send people under the ocean for years at a time to live on nuclear submarines in arguable more dangerous and isolated circumstance”

Mars is by orders of magnitude worse than living on a submarine.

> arguable more dangerous and isolated circumstances

I guess technically anything is arguable, but this seems absurd. Sure there's pressure and cold, but a submarine can hold 100+ people and surface in 10 minutes.

Mars is 10 months away with maybe 10 people. There's no surface. You can't scrub oxygen from the water, hell there's almost no water at all. You won't be crushed by pressure but you'll be bombarded by radiation.

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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.

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.

Good point, we don't have to exactly follow the "astronauts in a small tin can, where everything must work flawlessly" way. With Starship (or its future iteration/successor) we can:

- assemble a quite large interplanetary craft in orbit, with plenty of redundancy in HW and supplies

- drop 50 tons of cargo on Mars beforehand: food (and/or food-growing necessities - packaged soil, hydroponic equipment?), medical supplies, etc.; so that in case of problems, astronauts can survive on Mars for years if need be