One way or Return.

[B787_300]

Now the question as stated in the title refers to a exoearth mission, not to the moon, but to mars. With the cost of shipping fuel to orbit and other places in the solar system, to YOU does it make sense to send people on a one way trip, which would cost less, or send them in such a way that they could return after a half year or so on the surface?

One Way = there to stay pretty much indefinitely until they can produce their own fuel (at the least) or own rocket (at the extreme) to get back to earth. This plan would be similar to the MarsOne plan.

Return = the perfect mission, you send the people with a return craft, they stay on the surface for about half a year, and then travel back. This plan would be similar to most governments plans.

Poll up top and Debate below.

[Scotius]

I would like to think we, as a technological civilisation grew beyond the need for self-sacrificing, one way missions. Sure, in extreme cases there is little choice - but if we do have this choice it should really be last resort. Right now we don't have technical means and more important political will. But in 30-50 years it might change due to scientific breakthroughts and sociological developments. With new nuclear, plasma and fusion engines currently being developed mission to Mars would take about a month of travel one way - not too long ago sea trip from Europe to Asia or Australia would take as much, or even more time.

[Holo]

It will always be a return, because the people paying for the spaceflight won't want to associate themselves with sending astronauts to their death. Instead, a fuel factory (sabatier reaction or whatever it's called) will be sent there two years in advance, so by the time the astronauts get there they'll already have a ticket home.

To lower the mass costs of a two-way journey, you could separate it into multiple launches. The technology exists to soft-land a ton of payload onto Mars surface, so you could split the base into multiple payloads. By the time we do a manned mars landing (2035-2038?), that number will be larger.

Of course, this could all change if a country with less concern to human rights becomes spacefaring...

Edited April 21, 2013 by Holo

[Pyotor Gagarin]

Definitely return only.

For me, the idea of returning home from exotic places is inherent to the beauty of exploration.

Established colonies, with a full spectrum of society, can be allowed to grow beyond their immediate return capacity; but even then, return should be possible for people who want it.

[The Jedi Master]

Return. It's not a matter of expense or technology. It's a matter of ethics.

[Eric S]

Return, especially to lighter planets like Mars. While Mars would be harder to get off of than Duna, I'm assuming that Mars vs Earth is approximately equal to Duna vs Kerbin, and the Duna surface -> Kerbin landing trip is trivial compared to Kerbin surface -> Duna surface trip. I'm also assuming that we'd either manufacture fuel on Mars, or leave a fuel supply in orbit so we don't need to lift the transfer fuel back up from the surface of Mars. Even without either of those tricks, my most recent lander/ascent/return vehicle was a single stage with just under 2.3K delta-V, though it didn't use any of that for landing.

[NASAFanboy]

When the pilgrims landed on America, did they spend their time waiting for the England Return Vechicle? No.

[The Jedi Master]

When the pilgrims landed on America, did they spend their time waiting for the England Return Vechicle? No.

The pilgrims came from a bad place in a bad time to start a new life. The astronauts would not.

[B787_300]

The pilgrims came from a bad place in a bad time to start a new life. The astronauts would not.

Whos to say that? and the expense of both going to mars and crossing the oceans is comparable, yes it is a lot easier to cross oceans than it is to cross space, but most of them went to stay, not to go for a year and then return. Also there is no ETHICAL problem, we dont force people to go to space, we ask them and they say yes. It would be the same for a Mars Mission with the implication that they would not be able to return until the could produce the fuel for it.

[magnemoe]

When the pilgrims landed on America, did they spend their time waiting for the England Return Vechicle? No.

Some major differences, america was an shirtsleeve environment who could support the colonists without future missions.

They was also refugees, staying was another bad idea.

An Mars mission would require regular supplies like the IIS or an moon base.

It would be cheaper to return after 3-6 months than to continue to supply them for decades.

You would also want to explore various parts of Mars, doing multiple missions makes this more practical.

Yes you save delta-v with an suborbital jump, but hard to move the mars base, better to create an new one, as it's temporary you can use an far smaller one.

[Stochasty]

There's no point in going if you're only going to turn around and come right back. Exploration is better done robotically.

[metaphor]

The first human mission to Mars should be a return mission, if only to show that we can do it. The first mission would also validate human colonization technologies, such as being able to survive on the surface of Mars without resupply. Any future mission to Mars that is for the purpose of making a colony could be non-returnable, at least at first. Presumably by that time, if there is a dire need for a return system, it could be launched from Earth.

Many Mars return mission architectures use in-situ resource utilization (ISRU), which means the fuel for leaving Mars would be produced on Mars. So the fuel for leaving Mars would not have to be taken all the way from Earth, which is a pretty big cost saver and also makes a return mission come close in cost to a one-way mission.

For reference, the delta-v for a one-way mission in km/s would be 9.2 to get off Earth, 3.8 to get on a Mars transfer orbit, and about 1 to land on Mars (you need retrorockets, parachutes won't cut it in the thin atmosphere), for a total of 14 km/s. You would also need a heavy heatshield to land straight from interplanetary orbit. For a return mission, that would be 9.2 to get off Earth, 3.8 to get on a Mars transfer orbit, 1 to land on Mars, 4.1 to get into Mars orbit, 2.3 to get on an Earth transfer orbit, and 0 to land on Earth, for a total of 20.4 km/s. There are some savings possible on a return mission, such as leaving your Earth return vehicle in Mars orbit so you don't carry it to the surface and back, and ISRU would take care of the 4.1 km/s delta-v to get to Mars orbit.

So a one-way mission would be easier and cheaper, but not by much if you use some tricks for cheap return.

One source

Edited April 22, 2013 by metaphor

[Holo]

There's no point in going if you're only going to turn around and come right back. Exploration is better done robotically.

Exploration isn't the only reason to visit Mars. Also, some science could only be done with a manned mission, like "What happens when you lock 5 people in a tin can for several months and send it 90 million km away?".

[Nibb31]

Exploration isn't the only reason to visit Mars. Also, some science could only be done with a manned mission, like "What happens when you lock 5 people in a tin can for several months and send it 90 million km away?".

The same thing that happens when you lock 5 people in a tin can for several months in the Nevada desert. There is no need to go to Mars for that.

Actually, emigrating to Mars makes no sense. You would be living in a tin can, drinking recycled pee, eating hydroponic tomatoes, and you would never feel the fresh wind in your hair, the sun on your skin, or the rain on your face ever again. Your life would rely on a supply ship every 2 years, desperately hoping that there is still a budget for one. Not to mention no TV or internet.

If that's the kind of life you want to live, I can lock you up in a trailer in the Nevada Desert (preferably somewhere radioactive, like the White Sands Test Range) and promise to send you a supply truck every two years. It would be much cheaper, and the end result would be the same.

[Holo]

The same thing that happens when you lock 5 people in a tin can for several months in the Nevada desert. There is no need to go to Mars for that.

Actually, emigrating to Mars makes no sense. You would be living in a tin can, drinking recycled pee, eating hydroponic tomatoes, and you would never feel the fresh wind in your hair, the sun on your skin, or the rain on your face ever again. Your life would rely on a supply ship every 2 years, desperately hoping that there is still a budget for one. Not to mention no TV or internet.

If that's the kind of life you want to live, I can lock you up in a trailer in the Nevada Desert (preferably somewhere radioactive, like the White Sands Test Range) and promise to send you a supply truck every two years. It would be much cheaper, and the end result would be the same.

Which is why I'm a proponent for return trips.

There's also prestige. Which makes you prouder to live on this planet: we sent robots to the moon, or we send humans to the moon?

[B787_300]

but colonization and terraforming are essential for Humankinds survival over a long time frame, get it started right away is how i see it.

[metaphor]

The same thing that happens when you lock 5 people in a tin can for several months in the Nevada desert. There is no need to go to Mars for that.

Actually, emigrating to Mars makes no sense. You would be living in a tin can, drinking recycled pee, eating hydroponic tomatoes, and you would never feel the fresh wind in your hair, the sun on your skin, or the rain on your face ever again. Your life would rely on a supply ship every 2 years, desperately hoping that there is still a budget for one. Not to mention no TV or internet.

If that's the kind of life you want to live, I can lock you up in a trailer in the Nevada Desert (preferably somewhere radioactive, like the White Sands Test Range) and promise to send you a supply truck every two years. It would be much cheaper, and the end result would be the same.

You could say the same thing about astronauts aboard the ISS. They are living in a tin can, drinking recycled pee, eating dehydrated food, and they never feel the fresh wind in their hair, the sun on their skin, or the rain on their face. Their life depends on a resupply ship every 2 months, desperately hoping there is still a budget for one. They might have some internet on the ISS along with TV, but there's no reason you can't get TV on Mars too.

However, there is one thing you can do on Mars that you cannot do on the ISS, and that is to explore. You have an entire planet at your disposal, with the same landmass as the Earth. With a rover you can go to a new place every single day. Not to mention the science that can be done. A human geologist can do in one minute what it takes the Curiosity rover a whole day to do. Also you have access to plenty of raw materials. If you have some tools, you can build things, like shelters and domes. That is something that will probably never be done by robots alone, because of the 15 minute light-time lag.

People have endured much much harsher conditions than a Mars colony would face, during the course of Earth history. For example, until the twentieth century, all sailors were away from home for months at a time, with no human contact (no TV/internet/phone) other than the other sailors, and deplorable living conditions. They didn't have to bring their own air, but they did have to bring their own food and water. A Mars colony would live in much better conditions.

Also if you really really want to return to the Earth, Earth can send you a return vehicle for about twice the cost of a resupply ship.

I still think the first mission to Mars should be a return mission, but there's no reason we couldn't start a permanent settlement after that.

[The Jedi Master]

You could say the same thing about astronauts aboard the ISS. They are living in a tin can, drinking recycled pee, eating dehydrated food, and they never feel the fresh wind in their hair, the sun on their skin, or the rain on their face. Their life depends on a resupply ship every 2 months, desperately hoping there is still a budget for one. They might have some internet on the ISS along with TV, but there's no reason you can't get TV on Mars too.

The biggest difference is that the ISS crew does eventually return home. A one-way Mars mission, not so much.

[Holo]

The biggest difference is that the ISS crew does eventually return home. A one-way Mars mission, not so much.

Yeah. One-way mission to Mars are a terrible idea.

[Scoundrel]

IMHO a one-way Mars mission only makes sense if it is:

a) completely self sufficient, including in situ production capabilities of energy, consumables, and replacement parts.

done with the intent to colonize, so the investment can pay off dividends both scientifically and socially.

Anything less seems pointless for the investment.

[lump]

I would not mind a one way trip to mars, i never really like earth and always loved mars for its mystique. Yes yes you say i'll miss it when i'm gone but trust me, i'm really not that kind off person, i've drunk worse than recycled urine, and lets be honest, some of what we drink will have been piss at one time or another, i basicly live in my room anyway not doing much, i like learning and can easily be distracted with pretty much any slightly inteasting tasks, even trivial ones if i'm in the mood, i don't think they would like me playing KSP on the flight there though

but in all honesty it does seem a bit cheap, being a one way trip and all, it takes no where near as much fuel to launch people off mars, most of the problems i see are in the weight requirements, but if your sending down the means to live there you can sure as hell send a light rocket.

On another not i do like the way this suddenly popped up even though less than a year a go NASA said i would be at least 10 years before we go to mars.

A final note i said to my friends, you may have the internet while your on mars but the ping would be terrible.

[Holo]

A final note i said to my friends, you may have the internet while your on mars but the ping would be terrible.

By 2023, hard drives will be about 30 terabytes. Just download the whole internet

[metaphor]

IMHO a one-way Mars mission only makes sense if it is:

a) completely self sufficient, including in situ production capabilities of energy, consumables, and replacement parts.

done with the intent to colonize, so the investment can pay off dividends both scientifically and socially.

Anything less seems pointless for the investment.

Exactly. That's one reason I don't like Mars One's plan for Mars settlement. We need to perfect 3D printing and other advanced manufacturing techniques before we send people on a one-way trip to Mars, so that the settlement can be self-sufficient and is not entirely dependent on resupply. Mars has an abundance of raw materials which can be used to build things with the right tools, including shelters and eventually return rockets for transport to the Earth.

Until we have that technology developed, we should do missions that return. It's getting a little ahead to talk about Mars colonies when we don't even have a first mission in the works, that will hopefully tell us what is required to live on the surface of Mars.

[Czman007]

One way. Better to establish a colony early on than to make several return trips before making a colony. Plus once the colony is finished it could serve as a refueling station for later missions.

[OrbitalJoe]

One way missions manned missions don't make sense to me, as you'd have to resupply the crews regularly with food ect. from Earth (I don't see an entirely self sufficient Mars colony as a possibility on the first flight).

Much better to return, but with ISRU. You can use the CO2 atmosphere of Mars to make liquid oxygen. If you can get an 100kW power supply, liquid methane can also be produced (though you'd need the hydrogen from Earth, 5% of total propellant). This is an actual technology that's been demonstrated (been around since the 1800s), and not new-age far-future nonsense like VASIMIR or space elevators

-Joe