Confronting the Credibility Gap for Crewed Exploration of Mars • Hacker News Board

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#41

Post by semi-extrinsic » Wed, Dec 21, 2016, 11:58 AM UTC

jcoffland wrote: post #39

Radiation is a huge problem. Both en route and on Mars. A lot of these problems beg the question. Is Mars really the best target? Sure it's close but there are moons around Saturn that are interesting as well. Titan for example. Sure it's cold but it has a lot of atmosphere. Presumably landing would be easier. If we could learn to live underwater we could possibly visit Ganymede or Europa.

Radiation, as you mention, is a very big problem which is independent of destination.

Human psychology is another, perhaps even bigger problem, also independent of destination. We've had various experiments with prolonged isolation, but none where the subjects know that they're never coming back to Earth. I'd say psychology has a >50% chance of wrecking the first manned missions to other planets/moons, unless we send huge ships with hundreds of people.

In the Red Mars trilogy by Kim Stanley Robinson, the author has come to the very astute observation that

a) no perfectly rational, mentally healthy human would volunteer for such a mission

b) there will necessarily be extensive psychological screening to ensure we only send rational people

thus c) the people who will be selected are likely to be non-rational actors very good at concealing their non-rationality from psychologists. Also known as people with psychopathic tendencies.

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#42

Post by coldtea » Wed, Dec 21, 2016, 12:16 PM UTC

jcoffland wrote: post #39

Radiation is a huge problem. Both en route and on Mars. A lot of these problems beg the question. Is Mars really the best target? Sure it's close but there are moons around Saturn that are interesting as well. Titan for example. Sure it's cold but it has a lot of atmosphere. Presumably landing would be easier. If we could learn to live underwater we could possibly visit Ganymede or Europa.

>A lot of these problems beg the question. Is Mars really the best target? Sure it's close but there are moons around Saturn that are interesting as well.

You seem to imply that the issue of radiation should cause us to reconsider whether Mars is worth it. But the same, and worse, problem people will have with Saturn too.

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#43

Post by coldtea » Wed, Dec 21, 2016, 12:16 PM UTC

semi-extrinsic wrote: post #41

jcoffland wrote: post #39

Radiation is a huge problem. Both en route and on Mars. A lot of these problems beg the question. Is Mars really the best target? Sure it's close but there are moons around Saturn that are interesting as well. Titan for example. Sure it's cold but it has a lot of atmosphere. Presumably landing would be easier. If we could learn to live underwater we could possibly visit Ganymede or Europa.

Radiation, as you mention, is a very big problem which is independent of destination. Human psychology is another, perhaps even bigger problem, also independent of destination. We've had various experiments with prolonged isolation, but none where the subjects know that they're never coming back to Earth. I'd say psychology has a >50% chance of wrecking the first manned missions to other planets/moons, unless we send…

>Human psychology is another, perhaps even bigger problem, also independent of destination. We've had various experiments with prolonged isolation, but none where the subjects know that they're never coming back to Earth.

Who said they're never coming back to Earth?

>no perfectly rational, mentally healthy human would volunteer for such a mission

That's an easy problem to solve, as there are no "perfectly rational" and/or absolutely "mentally healthy humans", and have never been anyway.

And people can still be quite rational and mentally healthy and yet cherish the possibility to take such a mission, even if there's a possibility to die, etc.

In fact, it's needs no more troubled people than those that go to the army and are OK to be sent to war, or people that dive and explore the oceans, etc etc.

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#44

Post by LeifCarrotson » Wed, Dec 21, 2016, 1:06 PM UTC

lmm wrote: post #40

Animats wrote: post #26

Landing is really hard. Not enough atmosphere for aerobraking, and too far from home to have enough fuel for a powered landing. It's a fuel problem. There's the expensive approach. Send multiple unmanned tanker ships into Mars orbit and have them rendezvous into an orbital supply depot. Send landing tanker ship to rendezvous with them and refuel with enough fuel for a powered landing. Landing ship descends. Repeat to…

The "Red Dragon" missions are planning on the cheap approach, using a flattish (indeed rising in places) trajectory to extend the aerobraking long enough to be effective, combined with supersonic retropropulsion. We've got a lot better at fluid dynamics and lifting-body physics in the last few years, and SpaceX in particular is cleverly developing a lot of experience using the same "EDL technology stack" for their bo…

EDL = Entry/Descent/Landing, for anyone else confused.

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#45

Post by semi-extrinsic » Wed, Dec 21, 2016, 1:30 PM UTC

coldtea wrote: post #43

semi-extrinsic wrote: post #41

Earlier quoted context omitted.

Radiation, as you mention, is a very big problem which is independent of destination. Human psychology is another, perhaps even bigger problem, also independent of destination. We've had various experiments with prolonged isolation, but none where the subjects know that they're never coming back to Earth. I'd say psychology has a >50% chance of wrecking the first manned missions to other planets/moons, unless we send…

> Human psychology is another, perhaps even bigger problem, also independent of destination. We've had various experiments with prolonged isolation, but none where the subjects know that they're never coming back to Earth. Who said they're never coming back to Earth? > no perfectly rational, mentally healthy human would volunteer for such a mission That's an easy problem to solve, as there are no "perfectly rational"…

How are they going to come back? All realistic plans I've seen are for one-way trips.

The thought of dying isn't the inherently problematic part, but rather the extreme isolation. People who go to war are there for only some months and have plans for going home, back to friends and family. People who dive and explore the oceans are isolated for a few days at worst; perhaps months in a nuclear sub, but there you have already a pretty large crew around you. Compared to decades spent isolated with a handful of people, and no return ticket to the rest of humanity, those are nothing.

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#46

Post by daveguy » Wed, Dec 21, 2016, 1:37 PM UTC

jack9 wrote: post #31

daveguy wrote: post #14

Earlier quoted context omitted.

Everything in science starts out impossible. It doesn't even get considered in science unless it has a chance of being impossible. Then it is up to the scientist to demonstrate that it is possible and explain how it is possible. Edit: The 1) demonstrate and 2) explain parts are critical and it's not science unless you have 1). Preferably 2) also. EM has neither to match the magnitude of the claims until they can push…

> EM has neither to match the magnitude of the claims until they can push something across the solar system and back That is hyperbolic. Pushing something around in orbit is sufficient to move forward (pardon the pun).

Good point, but it would need to accelerate and decelerate in orbit enough to confirm that mass loss isn't driving it.

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#47

Post by coldtea » Wed, Dec 21, 2016, 1:48 PM UTC

semi-extrinsic wrote: post #45

coldtea wrote: post #43

Earlier quoted context omitted.

> Human psychology is another, perhaps even bigger problem, also independent of destination. We've had various experiments with prolonged isolation, but none where the subjects know that they're never coming back to Earth. Who said they're never coming back to Earth? > no perfectly rational, mentally healthy human would volunteer for such a mission That's an easy problem to solve, as there are no "perfectly rational"…

How are they going to come back? All realistic plans I've seen are for one-way trips. The thought of dying isn't the inherently problematic part, but rather the extreme isolation. People who go to war are there for only some months and have plans for going home, back to friends and family. People who dive and explore the oceans are isolated for a few days at worst; perhaps months in a nuclear sub, but there you have…

>How are they going to come back? All realistic plans I've seen are for one-way trips.

Huh?

"The first crewed Mars mission would be expected to have approximately 12 people, with the primary goal to "build out and troubleshoot the propellant plant and Mars Base Alpha power system" as well as a" rudimentary base." In the event of an emergency, the spaceship would be able to return to Earth without having to wait a full 26 months for the next synodic period."

https://en.wikipedia.org/wiki/Interplanetary_Transport_Syste...

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#48

Post by LeifCarrotson » Wed, Dec 21, 2016, 1:57 PM UTC

semi-extrinsic wrote: post #41

jcoffland wrote: post #39

Radiation is a huge problem. Both en route and on Mars. A lot of these problems beg the question. Is Mars really the best target? Sure it's close but there are moons around Saturn that are interesting as well. Titan for example. Sure it's cold but it has a lot of atmosphere. Presumably landing would be easier. If we could learn to live underwater we could possibly visit Ganymede or Europa.

Radiation, as you mention, is a very big problem which is independent of destination. Human psychology is another, perhaps even bigger problem, also independent of destination. We've had various experiments with prolonged isolation, but none where the subjects know that they're never coming back to Earth. I'd say psychology has a >50% chance of wrecking the first manned missions to other planets/moons, unless we send…

> no perfectly rational, mentally healthy human would volunteer for such a mission

That depends entirely on what they value. If they value their own safety, comfort, and health, then it wouldn't be rational for them. But if they value the advancement of future humans, honor, fame, legacy, scientific discovery, adventure, and so on (which may seem to be irrational things to value for someone in the first group) then it would be rational.

There are some people who will be excited about the fictitious ad from Earnest Shackelton "Men wanted for hazardous journey, small wages, and bitter cold, long months of complete darkness, constant danger, safe return doubtful, honor and recognition in case of success."

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#49

Post by IndianAstronaut » Wed, Dec 21, 2016, 2:04 PM UTC

jcoffland wrote: post #39

Radiation is a huge problem. Both en route and on Mars. A lot of these problems beg the question. Is Mars really the best target? Sure it's close but there are moons around Saturn that are interesting as well. Titan for example. Sure it's cold but it has a lot of atmosphere. Presumably landing would be easier. If we could learn to live underwater we could possibly visit Ganymede or Europa.

Titan may be a very good bet. It has an atmosphere so you aren't worrying if your water resources may boil away, or if a small tear in your suit hapens, you have more time to fix the situation.

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#50

Post by Jarwain » Wed, Dec 21, 2016, 2:19 PM UTC

Animats wrote: post #26

Landing is really hard. Not enough atmosphere for aerobraking, and too far from home to have enough fuel for a powered landing. It's a fuel problem. There's the expensive approach. Send multiple unmanned tanker ships into Mars orbit and have them rendezvous into an orbital supply depot. Send landing tanker ship to rendezvous with them and refuel with enough fuel for a powered landing. Landing ship descends. Repeat to…

I feel like a good first step would be setting up an orbital base/space station that orbits mars. It might be be a little easier than habitation On the planet itself, and more risk for the astronauts involved. However, if we set that up using knowledge gleaned from the ISS, I think its a viable path to take.