I've been torn between the wild success of the Mars rover program (coming up on 9 years of operation, despite a 90-day design-life), versus our inability to conduct a manned mission to Mars. I'm certain that we have retrieved much more scientific data with the robotic missions than we could have ever hoped for with humans, but the bragging-rights are much less. Growing up with the lunar program in the 60's, there was an incredible amount of pride we as a nation earned, and it fostered rapid growth in technology development. Today, there's a lot of dark and gloomy clouds overhead as we worry about outsourcing, a languishing economy, and how college graduates will pay-off their mountain of student loans.
One of the biggest obstacles to a manned mission to Mars -- besides getting there, of course -- is overcoming the Martian "gravity well" once it's time to leave. How do we bring enough propulsion energy along to get off the surface? We are nowhere near figuring out that problem, hence the debate about going to the Martian moons and their smaller gravity wells. The other option, of course, is to make a manned mission a one-way trip. There are plenty of explorers out there who would be willing to make such a trip.
There was a very clever idea developed by NASA about 20 years ago to solve the fuel problem: Synthesize it on Mars. The idea was to send a solar-powered fuel-synthesizer to Mars ahead-of-time, along with some liquid hydrogen. The plant would land, and begin synthesizing liquid oxygen and liquid methane from dis-associated atmospheric martian CO2 (O2 for liquid OX, C plus H2 for CH4 methane) . Given the low atmospheric pressure on Mars, this could take a very long time to make enough fuel.
@green_ee : "Today, there's a lot of dark and gloomy clouds overhead as we worry about outsourcing, a languishing economy..."
Compared to the problems of getting a man to the Moon or a rover to Mars, these seem almost trivial. All it would take is some political will and a curb on greed. And it issulstrates the differences between politicians and Engineers.
The space feats of the US show that in terms engineering talent, know how and foresight US is much ahead of the rest of the world and has a very rich scientific and engineering data base .
Other competitors may be decades behind as far as this strength is concerned.
Plenty of explorers willing to make the one-way trip to Mars? That's hard to believe.
Back when, explorers may have wondered if they would ever get back home, but at least they had air to breathe, and water and food available. This is not quite the same thing, eh? Whatever air and food is what you carry with you. Then you're history.
I think another problem with such a long mission will be spending so much time with either no gravity, or much less gravity than we have here. So that if a return trip is contemplated, your recovery period will be very long. I think we need to spin these spaceships. I've read that people might never fully recover from such long missions.