Four-man mission to Mars? No.

[EEVblog]

For now, we can direct our limited resources elsewhere - like towards a better propulsion system which will shorten time in space.

They aren't mutually exclusive.

[EEVblog]

Here's something I posted earlier:
"We must face a hard truth here.  At this point in the forward march of humanity, the forces of the universe have overpowered man's ability to penetrate it.  We tried to populate space, but we got bounced back.  The space shuttle fell back to earth and the International Space Station goes round-and-round in circles.  Mankind made it to the Moon, but has been retreating ever since - not because we don't want to go forward, not because of politics, but because the insurmountable challenges of penetrating the hostility and enormous distances of space are simply too great ... for now."

Repeating that doesn't make it right 
In fact it's demonstrably false. We could put humans on mars in a decade if we had the desire and budget.
Want proof?
Going to the moon was a gigantic leap of engineering and science faith at the time the call was made.
We didn't know if we could dock in space, navigate and work in space, survive the radiation, the moon and it's composition, have the rocket technology, have the computer and navigation technology required etc. And I could probably throw dozens of more thing into the mix of what we didn't know was possible.
Yet we did it, in under 10 years.

Now we know we can do all that stuff, and we know a ton about Mars and it's composition, and we have landed things on mars and other foreign bodies, and we have an infinite more computing and technology progress since Apollo. Various teams have prototypes running of Mars habitats and self sustaining technology etc.
We have long endurance space flight down pat. Ok, not so great for human health without artificial gravity, but that's beside the point.

And you seriously think we have "insurmountable challenges of penetrating the hostility and enormous distances of space are simply too great" ?
Apollo has to be an order or magnitude more complex than pulling off a Mars trip.

[stitch]

The point is once you have a human on board, that changes the game entirely.

Yes.  Here are some of the changes:
Kleenex
Toilet Paper
Socks
Underwear
Pajamas
Towels
… what am I leaving out?

[stitch]

And you seriously think we have "insurmountable challenges of penetrating the hostility and enormous distances of space are simply too great" ?

Yes. For now.

[Rigby]

You keep saying "for now" as if it is some capitulation that makes the rest of what you're saying palatable, or something.

I think you're just more interested in space tech than space exploration.  That's perfectly fine, just say THAT, if that's what you mean.

We can focus on more than one thing.  The budget limitations I was speaking of overcoming won't get us anywhere useful except working on multiple research and experimentation topics simultaneously.  It won't get better equipment into space, it will get us learning from our mistakes a LOT more quickly.

Dave is right about what we can do in a decade.  The original Gemini missions were purely a proving ground for the unknown quantities that are now known quantities.  Can people survive in 0G, what toll if any does microgravity have on the human body, can we dock vehicles reliably, can we get there and back reliably, can we do all the necessary stuff in order to "land a man on the moon, and return him safely to the earth" reliably?

That stuff is all proven and shaves years off of what we'd need to do to regain a presence on other planets and/or moons.

Yes, rocket tech is definitely part of it, and research proceeds in that area today.  How many more things could be tried and proven (or disproven) if budget was not an issue?  How much faster could research projects and trials be completed and advanced to next stages if there were 10x as many people on 10x as many projects?  OF COURSE more budget will help speed things up, and I think we would discover things we weren't expecting to discover if we branched out a bit and worked on research topics that weren't rigged to win from the start.

Right now, because of budgeting, only the MOST promising technologies see any real attention.  We can learn things from the less promising endeavors, too, and that is what really saddens me about current research.  I am not saying that we should throw a bunch of science to the wall and see what sticks, but I think we could be a little looser with what we pay serious attention to in the hope of stumbling across some advancement or discovery that would not have been found had we stuck only to the conventional stuff.

It is a travesty how little the US spends on space in comparison to how much we spend on war.  We talk the talk of returning to manufacturing, engineering, innovation, yet we throw so much money away on war.  Take half of what we spend on war, give it to NASA.  Take the other half and pay for college for everyone that wants to study science or engineering.  Give any leftovers back to the general fund.  Then just sit back and watch lots and lots of things (economy, business growth, GDP, education, sudden surge of tech innovation, etc.) improve.  EVERYTHING will improve in the long term.  Every. Thing.

[rob77]

The point is once you have a human on board, that changes the game entirely.

Yes.  Here are some of the changes:
Kleenex
Toilet Paper
Socks
Underwear
Pajamas
Towels
… what am I leaving out?

breathable air
carbon dioxide removal
fresh oxygen supply for breathing
drinking water
water recycling
food (lot's of food for a trip to mars)
waste collection (lot's of shit produced during that trip)
.....
and a shitload of others

it's really freaking complicated once you have to provide life support in a harsh environment.

[Rigby]

Those are all solveable, and actually SOLVED problems...  Not sure what you're getting at, really. 

The ISS gets resupplied, and unmanned resupply ships could be sent to Mars.  Could be sent to a ship in transit to Mars. 

There's nothing about any of that that would necessarily rule out a manned mission...

If I'm not seeing your point, please restate it.

[coppice]

Remember, humans have a 100% success rate attempting to land on a foreign object in space, save for Apollo 13 which blew up half way there, and the humans saved that mission. In fact, they could have continued and landed on the moon if they didn't care about getting back.

The Apollo 13 crew didn't save the mission. They saved themselves. They couldn't save the mission, because getting rock back to the Earth *was* the major part of the mission.

[stitch]

You keep saying "for now" as if it is some capitulation that makes the rest of what you're saying palatable, or something.

When I say "for now" I mean until we develop the technology (and we will) to shorten time in space via better propulsion or even time travel. 

[stitch]

I think you're just more interested in space tech than space exploration.  That's perfectly fine, just say THAT, if that's what you mean.

I'm very interested in space exploration. That's why I spoke up on this forum originally. What I oppose is diverting funds away from the successful path of space exploration that we are currently pursuing using probes.  While the dreamers are befuddling themselves over how to do an old-school stuffing of flesh and blood into a tin can and keeping it alive for two years just to say "we did it", the rest of us are supporting the steady stream of relatively low cost probes that are actually delivering results - and we resist those who are quick to talk about their dreams, but never say anything about the costs.

[stitch]

The ISS gets resupplied, and unmanned resupply ships could be sent to Mars.  Could be sent to a ship in transit to Mars. 
If I'm not seeing your point, please restate it.

That is my point.  You're gonna need a bigger boat.  As I said in my original post, like Christopher Columbus, you're gonna need a fleet ... just to keep the flesh and blood alive.  Now ... show me the money.  Then, please list all of the exploration you can't do because you spent so much money on the fleet.

[rob77]

Those are all solveable, and actually SOLVED problems...  Not sure what you're getting at, really. 

The ISS gets resupplied, and unmanned resupply ships could be sent to Mars.  Could be sent to a ship in transit to Mars. 

There's nothing about any of that that would necessarily rule out a manned mission...

If I'm not seeing your point, please restate it.

sorry to say this, but especially the part:

Could be sent to a ship in transit to Mars.

of you post is extremely funny  apparently you know literally NOTHING about orbital mechanics and transfer orbits

[stitch]

The point is once you have a human on board, that changes the game entirely.

Yes.  Here are some of the changes:
Kleenex
Toilet Paper
Socks
Underwear
Pajamas
Towels
… what am I leaving out?

breathable air
carbon dioxide removal
fresh oxygen supply for breathing
drinking water
water recycling
food (lot's of food for a trip to mars)
waste collection (lot's of shit produced during that trip)
.....
and a shitload of others

it's really freaking complicated once you have to provide life support in a harsh environment.

Thank you!

[Rigby]

Those are all solveable, and actually SOLVED problems...  Not sure what you're getting at, really. 

The ISS gets resupplied, and unmanned resupply ships could be sent to Mars.  Could be sent to a ship in transit to Mars. 

There's nothing about any of that that would necessarily rule out a manned mission...

If I'm not seeing your point, please restate it.

sorry to say this, but especially the part:

Could be sent to a ship in transit to Mars.

of you post is extremely funny  apparently you know literally NOTHING about orbital mechanics and transfer orbits

You have no idea what I know about orbital mechanics, and you seem to bring it up specifically to attack. 

I will bite, however.

So there are good times to launch a ship to mars and there are bad times.  You also want resupply ships, if you employ them, to arrive at regular intervals, potentially during the trip as well as after landing.  So, since the time to actually reach mars depends heavily on where the earth and mars are in their orbits at launch time, resupply ships can't be launched at regular intervals AND arrive at regular intervals. 

I don't know a lot about orbital mechanics, true.  HUGE thanks for pointing that out, by the way.  That must have taken a lot of courage and bravery.  Major life goal completed there, for you, potentially. Bravo.

I do know that there are complications to delivering things from a moving planet, to a moving planet, at specific, regular intercals, and that launch windows are finite things for a given flight plan.  Ships can travel at different speeds and one ship can overtake another safely.  They might move at different speeds so that they can launch during windows that fit specific arrival times, and arrive when needed.

I'm not sure what you wanted from me with that comment, but I wanted to explain my thinking.

Please remember to take advantage of my ignorance and point out every flaw in my logic.  I expect nothing less. 

We can land a spaceship on a specific effing asteroid.  If we can do that, we can rendezvous a supply vessel and a manned ship, in flight.

Have a lovely [your current time period.]

[rob77]

Those are all solveable, and actually SOLVED problems...  Not sure what you're getting at, really. 

The ISS gets resupplied, and unmanned resupply ships could be sent to Mars.  Could be sent to a ship in transit to Mars. 

There's nothing about any of that that would necessarily rule out a manned mission...

If I'm not seeing your point, please restate it.

sorry to say this, but especially the part:

Could be sent to a ship in transit to Mars.

of you post is extremely funny  apparently you know literally NOTHING about orbital mechanics and transfer orbits

You have no idea what I know about orbital mechanics, and you seem to bring it up specifically to attack. 

I will bite, however.

So there are good times to launch a ship to mars and there are bad times.  You also want resupply ships, if you employ them, to arrive at regular intervals, potentially during the trip as well as after landing.  So, since the time to actually reach mars depends heavily on where the earth and mars are in their orbits at launch time, resupply ships can't be launched at regular intervals AND arrive at regular intervals. 

I don't know a lot about orbital mechanics, true.  HUGE thanks for pointing that out, by the way.  That must have taken a lot of courage and bravery.  Major life goal completed there, for you, potentially. Bravo.

I do know that there are complications to delivering things from a moving planet, to a moving planet, at specific, regular intercals, and that launch windows are finite things for a given flight plan.  Ships can travel at different speeds and one ship can overtake another safely.  They might move at different speeds so that they can launch during windows that fit specific arrival times, and arrive when needed.

I'm not sure what you wanted from me with that comment, but I wanted to explain my thinking.

Please remember to take advantage of my ignorance and point out every flaw in my logic.  I expect nothing less. 

We can land a spaceship on a specific effing asteroid.  If we can do that, we can rendezvous a supply vessel and a manned ship, in flight.

Have a lovely [your current time period.]

my point was mainly that it's impossible to re-supply a ship in flight to mars - and that was your statement exactly
of course it's possible to send supplies first and then the human crew and later on send supplies again during the next opportunity for a flight to Mars, but there is  no way to resupply a ship in flight to mars. in fact you would have to fly to Mars with something comparable in size to half of the ISS , or the size of older MIR space stations in order to provide life support for more than 8  months without resupply.

and regarding the different speeds for spacecrafts... there is a practical limit - the amount of fuel vs. mass - so it's always the escape velocity + the necessary delta-V for the task to save as much as possible. doesn't matter whether it's a flight to mars or moon or whatever other flight.

[Rigby]

Right about the escape velocity.  You don't have to launch from earth though.

[stitch]

Right about the escape velocity.

Don't forget about deceleration when you get to Mars.  In addition to hurling a huge mass of life support to Mars, you also have to hurl a huge mass of fuel and engines to bring the huge mass of life support to a dead stop.

[SeanB]

Launching from orbit merely decreases the mass that you are carrying along as used propellant holding. You still need to lift all the fuel up a gravity well and get it to 12km/s, then use a little in orbital manoeuvring and in holding while waiting for the main crewed vehicle to get there.

So you launch eg 5 Arianne 9 rockets into LEO, all into the same orbital plane and then use the second stage engines and reaction control to get them into a close constellation, and still have about 20% of each fuel load in tankage, and then have a third stage that is mostly supplies in containers that will be strapped to the transfer vehicle. Then launch your crewed vehicle to achieve the same orbit with enough fuel to either abort back or go for matching. then the difficult task of catching each stage, coupling to it, firing ullage motors to allow the fuel to flow via a pump,and transferring supplies to get a fully fuelled transfer vehicle. Each depleted tank must then have enough fuel to deorbit safely. Once this is done then you will have your Mars vehicle with a full fuel and supplied load.

[HackedFridgeMagnet]

I heard this game is good for learning about space trajectory plotting. Haven't played it though. There is a demo.

https://kerbalspaceprogram.com/about.php

[Alex Eisenhut]

Blue circle = Earth.
Moon = d

ISS = a

Just saying.

[Alex Eisenhut]

Blue circle = Earth.
Moon = d

ISS = a

Just saying.

http://www.distancetomars.com/

Any questions?

[HackedFridgeMagnet]

Any questions?

whats b, c and e?

[Alex Eisenhut]

Any questions?

whats b, c and e?

OK that right there was hilarious!

http://physics.ucsd.edu/do-the-math/2011/10/why-not-space/

[atferrari]

In voyage not to Mars but from Canada to Italy, two days before crossing Gibraltar strait, I got my left ear infected with the added bonus of a horrible pain. No nurse nor doctor on board.

In 40 hours I lost my hearing capability thus nowadays I can perceive just noise (if strong, I cannot avoid the pain it causes).

The otolaryngologist at Ravenna confirmed that the nerve had died.

The sole time in 17 years at sea I suffered a serious disease.

[wraper]

Don't understand that bullshit about doctors. Well, of course there is a risk that someone gets sick, but:
1. Space crew members are selected very seriously so only healthiest will pass.
2. They definitely will receive medical training, and will have remote support from experienced doctors on earth. So unless they need surgeon, there is no real use of doctor on board. As medical capabilities will be limited anyway (medicine, medical equipment), I don't see any real advantage what real doctor could give.
3. There will not be any other infections rather than those which could be taken on board before the start. -> look look paragraph 1. Therefore someone cannot catch flu, hepatitis or whatever unless it was already there.
4. Of course serious disinfection/inspection will be made so no pathological bacteria/viruses pass on board.

Therefore unless someone gets very seriously injured (where?), I don't see real problem. You know, even nowadays there are hermits and tribes who live for decades in the wood, mountains or name it. They do not have any modern technology, medical care, any medicine, nothing, yet they manage to survive somehow. Only very serious issue is absence of earth gravity which of course negatively impacts men's health.