Comment by ETH_start | Hacker News Reader

Comment by ETH_start | Hacker News Reader

I reluctantly upvoted this for the wealth of scientific/engineering knowledge it contains despite strongly disagreeing with some of its conclusions:

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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.

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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.

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.

> overall effects on the body 0.3g will almost certainly end up being closer to 1g than 0g

But what do you base this on? Vibes? Because the article correctly points out that:

> This goes against our intuitions, but there have been bigger surprises in space.

Most of the major negative effects from time in 0g are pretty easy to derive from first principles - like the loss of bone density and muscle mass. The cause is simply a lack of muscular exertion. In 0g you don't really have much of any recourse against this except lots of mostly elastic based exercise, so astronauts on the ISS spend 2+ hours every single day just exercising, and it still isn't enough. On Mars the deterioration will obviously be lesser. And you also have much easier solutions not only in terms of working out but also passive, like the proposed body suits.

Also I'd add that even the less well understood issue like vision decline generally has to do with things 'not going the right way' -- in this specific case 'stuff not going down' increasing the pressure on your ocular region (ever noticed how astronauts all seem to have kind of bloated heads while on the ISS?). On Mars (or any other body with some reasonable degree of gravity) these sort of things won't be a problem.

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

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