The first US mission to Mars was in the 1960s, and resulted in a near-miss. Despite not entering orbit, the probe was instructed to take pictures while zooming by and send the data back to Earth.
If the math is off, it’s off — and with humans aboard, a near-miss means death, not to mention failure to carry out the mission.
IMHO the human missions to Mars should be to a permanent space station in orbit around Mars; from there astronauts could direct a whole series of rovers to explore large chunks of the surface basically in real time. And the long exposure to microgravity and size of the station and transit vehicles would mean dozens of astronauts in space all the time, either going there, coming back, or in orbit around it.
Once we’ve got the hang of this and have safety built into the program — that was the Von Braun model — the landing / reorbit vehicle could be sent and tested (sans crew) prior to the first human Mars landings, or boots on the Mars ground. For the surface, imho we’d need something like a big motor home, but with tank treads or the like. The crew would land near it, cross the surface on foot, board the vehicle, then explore the surface in a shirtsleeve environment. After some weeks and many miles, they rendezvous with a different reorbit vehicle and return to the station.
first close-ups (July 14, 1965):
http://www.google.com/images?q=Mariner+4&sa=X&oi=image_result_group
more about the landing (AP source):
have I ever heard of this?
Mars One plans to establish the first human settlement on Mars by April 2023.
http://mars-one.com/en/mission/mission-and-vision
hey, wow! Nice illustration of this landing:
High-stakes Mars mission relies on untried ‘sky crane’
by William Harwood
July 31, 2012 8:32 AM PDT
http://news.cnet.com/8301-11386_3-57481959-76/high-stakes-mars-mission-relies-on-untried-sky-crane/
I need to watch the video. The “sky crane” sounds like an odd cartoon contraption - I’m thinking Dr. Seuss. The craft hurdles towards Mars. At the last minute it stops, deploys the sky crane from itself, and then lowers itself by the sky crane to the planet.