Landing people on Mars: 5 obstacles • Hacker News Board

Re: Landing people on Mars: 5 obstacles

#11

Post by lumberjack » Sun, Sep 02, 2012, 2:38 PM UTC

elorant wrote: post #3

I never understood why we abandoned the Moon. It’s only three days away compared to the eight months it takes to get to Mars and it also has water. We should first establish a base on Moon and then venture on to other planets.

There are two schools of thought on how we should approach manned Mars exploration:

1. The incremental approach, the NASA favorite, the outrageous proposal that got dismissed due to budget costs. It involves build a base in orbit or on the moon and using it as a relay between Mars and Earth.

2. Mars Direct. Reducing a lot of the complexity of the incremental approach. Using available technology. Launching directly from Earth. Using a multitude of vessels to setup an outpost on Mars before human arrival. Generating oxygen and hydrogen before human arrival from the abundant methane on Mars. Cutting the previous budget proposal by more than half. An estimate of ten years of work required.[1]

Both have their advantages and disadvantages. Mars Direct seems like a more realistic and pragmatic proposal but the incremental approach is more visionary. Something that most of us laymen don't often consider is the aftermath. We see the objective a human working on the red planet whereas I believe most at NASA are more interested in prolonged human exploration of Mars.

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

Re: Landing people on Mars: 5 obstacles

#12

Post by danielweber » Sun, Sep 02, 2012, 2:40 PM UTC

and the higher the odds of a catastrophic collision with a meteoroid

This is silly. The dangers to a mission from a meteroid are essentially the same for a six-month mission as a six-day mission: nil when compared the to the risk of blowing up on the launchpad.

Chang-Diaz is developing an advanced plasma propulsion system that would cut the round-trip time on Mars missions to five months

Ugh. We can already get to Mars in six months using chemical rocket engines right off the shelf. If Chang-Diaz thinks people can accept nuclear reactors in space, then we should just pull out the Nuclear Thermal Rockets we've already built and use them instead.

EDIT: I now see he is saying roundtrip being 5 months. This doesn't violate the laws of physics, but it does require nuclear reactors in space with massive energy-to-mass ratios, well beyond anything we've built for anything on the ground or in space before.

Spacecraft propelling astronauts to Mars — and habitats on its surface — must be equipped with shielding sufficient to block space radiation.

Or you can just take your dose. The cosmic ray dose from a round-trip Mars mission would increase your chance of cancer over your lifetime from about 20% to about 21%. This isn't something you would want to expose the general public (or even the janitor in a nuclear power plant) to, but it's petty when talking about the risks to crew safety from the Mars mission. Launching a extra spare habitat or earth-return-vehicle to Mars will be a better bang-for-the-buck in terms of decreasing mission risk, with the bonus that we need to do it anyway.

(This is different from blocking solar flares. Those can and probably will kill the crew dead if they aren't shielded from those. But that shielding is more straightforward as the article says.)

Re: Landing people on Mars: 5 obstacles

#13

Post by jschuur » Sun, Sep 02, 2012, 2:42 PM UTC

Kilimanjaro wrote: post #5

Terraform the moon first.

The Moon's gravitational pull wouldn't be enough to retain an athmosphere:

http://suite101.com/article/why-there-is-no-atmosphere-on-th...

Re: Landing people on Mars: 5 obstacles

#14

Post by drcube » Sun, Sep 02, 2012, 3:05 PM UTC

Why isn't artificial gravity considered a solution to extended periods of microgravity? Just spin the ship at the right speed and have the living quarters on the outer rim.

Re: Landing people on Mars: 5 obstacles

#15

Post by drcube » Sun, Sep 02, 2012, 3:09 PM UTC

elorant wrote: post #9

Almaviva wrote: post #7

The sex issue is just frivolous. E.g. I haven't had anything but rejection from a woman in three years, I'm perfectly healthy and functional, and I'm not being carefully chosen for one of the most groundbreaking missions for the human race.

Yes but I guess the women who rejected you don't live in the same house as you do. Imagine living in close quarters with a bunch of people and some of them are having sex while you don't. You'd have to seclude yourself from them to suppress your feelings and then the whole project would go south.

So you get a set of known stable monogamous couples to go. Or one big polyamourous family.

Re: Landing people on Mars: 5 obstacles

#16

Post by apendleton » Sun, Sep 02, 2012, 3:11 PM UTC

drcube wrote: post #14

Why isn't artificial gravity considered a solution to extended periods of microgravity? Just spin the ship at the right speed and have the living quarters on the outer rim.

It is. From the article: "A rotating spacecraft would create artificial gravity that would keep astronauts in tip-top shape."

Re: Landing people on Mars: 5 obstacles

#17

Post by 7952 » Sun, Sep 02, 2012, 3:16 PM UTC

drcube wrote: post #15

elorant wrote: post #9

Earlier quoted context omitted.

Yes but I guess the women who rejected you don't live in the same house as you do. Imagine living in close quarters with a bunch of people and some of them are having sex while you don't. You'd have to seclude yourself from them to suppress your feelings and then the whole project would go south.

So you get a set of known stable monogamous couples to go. Or one big polyamourous family.

That couldn't possibly go wrong.

Re: Landing people on Mars: 5 obstacles

#18

Post by S4M » Sun, Sep 02, 2012, 3:31 PM UTC

"The long voyages in weightlessness are bound to substantially debilitate the crew," he added. "At Mars arrival, they must have a way to rehabilitate themselves before going to work, a tall order for the first mission in a very hostile environment."

Is that really a problem as gravity is much lower on Mars than on Earth?

Re: Landing people on Mars: 5 obstacles

#19

Post by nkoren » Sun, Sep 02, 2012, 3:31 PM UTC

apendleton wrote: post #16

drcube wrote: post #14

Why isn't artificial gravity considered a solution to extended periods of microgravity? Just spin the ship at the right speed and have the living quarters on the outer rim.

It is. From the article: "A rotating spacecraft would create artificial gravity that would keep astronauts in tip-top shape."

Strangely, the article fails to follow this up with the next logical sentence, which is:

"Also, a rotating spacecraft is trivially easy to implement, meaning that the entire zero-gravity argument is nothing more than a ridiculous canard by those who'd rather suck down a few more tens of billions of pointless microgravity biomedical research before allowing us to leave Low Earth Orbit and do anything interesting."

Re: Landing people on Mars: 5 obstacles

#20

Post by drcube » Sun, Sep 02, 2012, 3:43 PM UTC

7952 wrote: post #17

drcube wrote: post #15

Earlier quoted context omitted.

So you get a set of known stable monogamous couples to go. Or one big polyamourous family.

That couldn't possibly go wrong.

Certainly things could go wrong. But I would argue having a set of people in established, stable relationships is better than either A) having unattached astronauts who will inevitably try to start relationships with each other, leading to a dangerous space soap opera, or B) having a unisex, hetero crew and expecting them to be celibate for years with no problem.