From: Hobart, Tasmania, Australia
ORIGINAL: Jim D Burns
A true hero has left us, rest in peace Mr. Armstrong.
A big part of our History.. one would've thought that we would've landed on Mars by now..
Landing on Mars today would be relatively easy Compared to how hard and dangerous landing on the moon was in 1969. But taking off again is still just about impossible even with today’s tech.
The cost of shipping and landing enough fuel for a takeoff from Mars would probably bankrupt half the countries on the planet today, so until we can find a way to make the fuel for the return trip on Mars itself, or a new type of interplanetary propulsion is invented, Mars is probably going to be out of the grasp of human footsteps for a long time to come.
No. A manned mission to Mars would be an extremely difficult and dangerous mission. The actual landing might be relatively easy but everything else is very hard.
1. The Moon is 4 days away, and as Apollo 13 showed, if something bad goes wrong, that's close enough to have a chance. Mars is a very long way away, even at closest approach to the Earth.
2. Using Hohmann transfer orbits (conventional orbital mechanics), Mars missions are essentially at least a year in length. If you want to spend any real time on the surface, which you would probably want to do after spending zillions of bucks to get there, you're looking at three.
There are numerous obvious problems with several people cooped up in a small space for such lengths of time but they have been mostly dealt with in the past, although only when in near instantaneous contact with Earth; not a luxury you have on a Mars mission.
The real deal-breaker is radiation. You might be able to protect the crew to a reasonable extent on the way to Mars with propellant tanks etc, but on the way back those will mostly be gone. As a result, sober planners now admit that much faster transit times will be necessary.
3. This means new propulsion technologies, and several have been shown to work, but developing them in the scale required and man-rating them will cost time and lots of money. There is also the risk that they won't start/restart after a very long period with no maintenance, dooming your crew.
4. Making chemical propellants to get off the surface of Mars using In Situ Resource Utilisation (electrolysis of water ice to form hydrogen and oxygen or generating methane and oxygen from carried hydrogen and Martian carbon dioxide) would probably be one of the easier parts of the engineering. Alternatively you can use nuclear thermal propulsion, possibly with Martian CO2 as the propellant to get back into orbit. Other options won't work. You need lots of thrust to get off a planetary surface and that means chemical of nuclear thermal rockets.