Inspired by this thread, Lets talk about the possibility of sending and returning humans from Earth to Mars.
Personally I think the whole point is fruitless. We can send robots to sniff out whatever we want. Sending humans is expensive, risky, and pointless.
Landing a capsule on Mars in the traditional parachute manner is damned near impossible due to the low atmospheric pressure on Mars (about 0.6% of Earths.) So how do we get a crewed capsule down to the planet?
If we can land, and forget about all of the feeding and nurturing in between, how do we lift off? Mars has 10% the mass of Earth and only 38% the gravity of Earth; but that still requires some infrastructure to blast off and assume escape velocity.
And what about food for the potential months the astronauts will be there?
ETA: Yikes! I meant this to be a separate thread. Hold the phone!
Leaffan, I like the idea of a Mars mission thread. I have no problem with doing it here, but it would probably get more traffic as a separate thread. I wouldn’t be able to contribute much but I’d read it!
There is less and less reason to send humans anywhere in space as technology advances. So much of the budget and payload is dedicated to life support instead of research.
Now, I remember being awed by the moon landing, and want NASA to be better funded, but I regard manned space travel as a needless luxury.
In a simple-as-I-can explanation, and what I learned from ‘space forums’, one of the biggest issues is the fuel and weight of such. You have to go fast to get there, and then slow down once at Mars vicinity. And still have enough leftover after landing to relaunch the appreciable weight of the ‘capsule’ that person(s) must live in for year+ (IIRC) of return voyage. That takes significant weight of fuel to launch - which is a HUGE rocket to begin with. The size/weight of rocket at launch is an obstacle that is being overcome slowly, but its a significant challenge to keep weight down to resonable costs, size of capsule/stages of rocket, etc.
And yes, the low density of atmosphere will be of little help overall in reducing velocity of the mass of capsule needed once its on ‘final approach’ to ground of Mars. There is a need for a much larger fuel capacity for slow-down purpose than Apollo’s requirements to land upon Moon. The ways we have succesfully placed rovers on Mars (bouncing with big ol’ ballons after chutes/fuel expenditure of smallish propulsion units used to hover the platform that lowered a rover by cable to ground, etc) and the fact that there was no need for return trip pale in comparison to weight of fuel needed to get back safely in a timely manner (in a nutshell anyways).
I’m sure I am missing more details, but that is kinda the gist of the hurdle(s) of getting to Mars and back.
I understand it’s a 6 month trip each way and a 1 year layover to wait for the most advantageous (i.e. shortest and fastest) return trip. So, they’re going to need to bring along 2 year’s worth of food and other expendables.
That reminds me… besides the hover cars, where are the food pills they promised us??
I thought that they will accelerate half way, then turn over and decelerate the rest. This will give then some artificial gravity as well.
Wasn’t there a suggestion to launch from the IST?
There would surely have to be a number of unmanned supply drops before launching to provide life support and fuel for the return. I imagine that the main ship would stay in Mars orbit and just send a lander down.
That might require some unobtanium (or maybe cavorite). With today’s technology, so far the longest we’ve been able to accelerate to escape Earth orbit is about 20 minutes (total burn time).
I ditto the idea of pre-supplying the mission.
All the food, equipment, the lander, fuel for the return trip, etc. should be sent beforehand and landed or parked in orbit. That could all be sent along slow (years long) but fuel-efficient trajectories. The humans would travel in a fast, expensive trajectory in a module designed just to get them there alive. The booster, fuel, and supplies for the return trip would be at Mars waiting for them.
I don’t disagree that it’s risky, very difficult, and that we probably won’t achieve it any time soon, but I don’t agree on the pointless thing.
Humans are more versatile than any robot we can build. A human - even suited to survive the Martian environment - can cover a lot more ground, turn over a lot more rocks, retrieve and study a lot more samples, etc than a robot can do in any unit time.
If life once existed (or still holds out somewhere) on Mars, a team of human paleontologists and geologists could discover it in a matter of days or weeks.
The trouble is that they aren’t more versatile than the many dozens to hundreds of robots we could build and send to Mars for the cost of sending a human.
Among numerous other advantages, the many robots could explore many places, extending over much of the planet’s surface. A human visit would certainly be limited to a modest area.
I’m in the camp that human space exploration will never be economically justifiable, but if we’re assuming that we actually do send humans to Mars I believe it would be best to leave them in orbit. Save the expense of landing them and blasting them back up and use them instead as drone pilots, controlling the rovers from above. The existing rovers on Mars are controlled in a very tedious process of sending instructions to move or do something else, waiting for pictures and data to return, and calculating the next instruction set to send. Human pilots in orbit would definitely speed that up.
The Apollo program was more or less sixty years ahead of it’s time; we;re only now building rockets for other purposes that are big enough to support ambitious manned missions as a side benefit. In terms of pure technology we could have sent people to Mars anytime since 1970- but it would have been like trying to establish a permanent base at the south pole by dogsled. I think we’ll only go to Mars when it can be done with “off the shelf” boosters and equipment; if we have to design a Mars mission from scratch, it’ll cost too much.
Re. humans versus robots: One proposal is to send humans just to Mars orbit so they can teleoperate rovers and samplers in real time. Kinda disappointing but practically much better cost/benefit ratio. ETA: ninja’d
