The Mars One mission plan at the moment is not per se a
sure suicide mission in that the astronauts are not determined statistically to 100% to just all die on the way or at any particular time after arrival on Mars in the habitat. It simply does not have a return voyage capability. In other words, it must honestly be described as a one way trip, but there is no reason other than cost and current logistics that a return method could not be developed. The Mars One mission on the surface is designed with ongoing subsurface ice water extraction, O2 production and a shielded habitat station with hydroponic food production and sanitary waste recycling facilities. Ongoing surface explorations, sample collecting and research are planned as well.
As it is now on paper, the very best case scenario is permanent exile with an indeterminedly shortened life span. Probably a very shortened lifespan, but it is unknown, and could be, maybe, on the order of a decade of survival on Mars, at the statistically extreme end, best possible projection.
Recall the moon landings; the lunar lander blasted off back into lunar orbit, coupled with the command module there, the two EVA astronauts them climbed back into the command module, and rode back home within the module (which did a gravity sling shot maneuver to get back - using the momentum from staying in a very fast orbit around the moon during the mission). All of the moon landing missions were honestly and essentially suicide missions as well, since the calculated odds of failure were on the order of 50% or worse, even with the planned return trip aspect.
It is essentially honest and correct to call Mars One a suicide mission. It is inherently very high risk, and even if the astronauts survive long term, they would still have debilitated health and body strength. Long term stays in low, near zero gravity are harmful, which would be the case on the voyage out, plus Mars has a little more than one third the Earth's gravity. Shielding from cosmic ray damage while on board the ship is inevitably inadequate, because not enough shielding can be installed due to weight restrictions since they are taking off in the voyage vehicle from Earth, and not from a voyage vehicle built at an orbiting station. It takes 85% or more of the total mission's rocket fuel just to blast off and escape Earth's gravity well.
Working within Mars One's proposed budget, it is not possible to build and use something like the lunar lander and command module return vehicle; the Mars One voyage vehicle gets abandoned. The reason is that it is many orders of magnitude farther away, and longer in duration (using up life support stores) and more complicated to achieve a there-and-back vehicle system to Mars versus the short jump to the Moon, which had the Earth right next door, just a short hop across the lunar to geo Lagrange points away. It was essentially all done with the gravity sling shot method, nearly no fuel other than navigation adjustment jets and very brief main engine fuel burns. The difference between the lunar and Mars One missions boils down to the "Mass Effect"
, as we know it in reality today.
