The main reason I say one way? Given it is an 21 month minimum round trip or even five years, the health (mostly bone density) issues are astounding. So, let the people decide to be the first Martian colonists and let it be a one way trip. If the preparation package was sufficient I know I would like to put my name down but I suspect that my wife wouldn't, so that vetoes me, but I know I am not alone.
Perhaps it is the idea of people dying in space and the publicity from that that worries those in charge. But lets remember that these trips aren't without risk, so lets say that the risk is better managed if they just stay on Mars.
Total colony failure is a real danger for Mars colonization, as it was for historical settlers. If our first Mars colony is a total loss, you can bet there won't be another one. If Martian settlers had space faring capabilities they could avert this scenario and potentially even return to Earth if things got out of control.
Establishing back-and-forth routes, both slow robotic ones, as well as the occasional human shuttle, means Mars will be a real extension of Earth instead of a stagnant, extreme colony. It means there will be pressure for technological advancement in this area which wouldn't be necessary if we had just a big one-way rocket. Without this pressure, spaceship design and propulsion won't get a significant boost.
If we choose to put this one-way barrier up, let's not kid ourselves, it will be because it's dramatic and romantic. In the short term, this decision will put human lives in danger. It will stifle innovation by willfully ignoring a big tech application. Over the long term, if the colony survives, it will lead to a technologically superior Mars that has no meaningful ties to Earth - and with that, potentially, war.
Having a two-way system in place will most likely finally commoditize space travel and in one fell swoop will eliminate all the problems I talked about.
> Perhaps it is the idea of people dying in space and the publicity from that that worries those in charge.
Humans will die "in space" anyway. If we choose to venture out into the solar system, people are going to die out there. As I said, a one-way transport system combined with a loss of the first colony will result in a lot of deaths and it will result in a total cancellation of any further colonization efforts.
Making transports one-way is a choice, not a necessity. I would argue it's an illogical one with very impractical consequences.
I agree that one-way trip is the best, because of difficulty to acquire fuel.
I'm not talking about some starship enterprise, but something a little meatier than a glorified coke can.
You should check out the Mars Direct plan proposed by Robert Zubrin. https://en.wikipedia.org/wiki/Mars_Direct
[1] https://www.youtube.com/watch?v=uDWvsdEYSqg (I don't know the copyright status of this, but it's been on YouTube for well over a year with many views).
[2] Robert Zubrin. The Case for Mars.
Perhaps the private sector can take this one on?
Gemini 11 had some success with a similar scheme involving tethering themselves to their Aegena craft and spinning up. However this was far from straightforward and only created tiny amounts (Wikipedia says 0.00015g) of artificial acceleration.
In order to get 1g from a 50m tether it would have to spin at a little over 4rpm, which seems like quite a lot for such a big thing. Also the difference in acceleration between an astronaut's head and feet would be something like 0.3 m/s/s, which hasn't (AFAIK) been tested.
The Gemini experiment was amazing (especially given it was some way down the list of mission objectives) but I don't think it qualifies as a full demonstration of the technique. I know this project is not intended to be a finished design, but they give the impression that artificial gravity generation is a solved problem.
