THIS linked article from ABC News illustrates why our manned space program isn't much farther along than it is.
Every four or eight years, either we elect a new president and/or a new political party takes power, and the space program undergoes yet another overhaul. Programs that have been moving forward for years are often suddenly disrupted, delayed, or canceled altogether. The history of NASA is literally littered with the epitaphs of otherwise promising projects like the SSTO or X-33/Venturestar.
Unfortunately, space has proven too difficult an environment in which to do anything quickly or easily. Apollo with its breakneck pace of historic accomplishments turned out to be the exception, not the rule. We need long term commitment to a single vision of space exploration/exploitation in order to really accomplish any major worthwhile goals.
Though I doubt we'll ever see one any time soon, what we should have is a national referendum on space. The public should weigh in on exactly what we should try to accomplish in space, and whatever administration is in power should follow that as a guideline, instead of just canceling or downgrading projects out of spite against the previous administration, something both political parties have been guilty of for decades now.
But which general plan would the public back? Actually the best way we can decide this is educating people on the general directions the space program could take.
As an example, four feasible general strategies are outlined below. It should be noted that none of these are mutually exclusive; one can eventually lead into one or more of the others very easily.
Return to the Moon: This is the strategy outlined by the Bush administration in 2004, which NASA had been working toward since. I should note that I was not a fan of many of the previous administration's science policies, but I do think its 'refocusing' of the manned space program was spot on, especially since the retirement of the shuttle fleet was inevitable. The Constellation vehicle system under development was specifically geared for this mission.
The purpose of this strategy was not only to send more Apollo-style manned missions to the Moon, but to establish a permanent manned presence there in the form of a moonbase. The advantage of a Moon goal is that it has been underway for half a decade now and is already fairly well developed. As a result it could probably be achieved sooner than the other strategies outlined here. Also, the experience of building and maintaining the ISS would come in very handy in creating a slowly expanding moonbase. For long term benefits, the Moon offers vast resources, particularly the potential fusion fuel helium-3, that could produce a potential windfall for any country that gain a significant lead in developing them.
Mars: The second most talked-about path, many Americans want to forge directly ahead to the Red Planet on one or more grand voyages of human discovery. It is perhaps the most romanticized of the strategies, very appealing to generations of Americans who grew up on the space exploration adventures of various scifi heroes.
The advantage of this plan would be mostly in the technology that would developed in order to make it viable; namely long-term space habitat systems and true interplanetary manned spacecraft. The human exploration of another whole planet would also be very valuable, conducting observations and experiments that current robotic probes aren't easily capable of. But more, a human being stepping onto the surface of another planet would be a monumental historical event that would resonate for generations.
Going to Mars would be the longest-range goal discussed here because of the immense distances and logistics involved, and could actually incorporate a return to the Moon and/or a manned asteroid rendezvous as an intermediate step.
Orbital Infrastructure: Instead of manned exploration, NASA concentrates much more on building up potentially useful and profitable structures in Earth orbit. This is not necessarily a stay-at-home strategy. Post-Apollo, NASA had a 'Grand Architecture' vision for space, focusing on building up a 'step ladder' of stations leading out into the solar system. The shuttle and the ISS as they were originally envisioned were just the first two major projects of this architecture.
In this vision, NASA maintains the ISS as long as possible and follows up with bigger, more advanced stations, as well as other useful orbital structures, such as solar power satellites, orbital hot labs, zero-g factories, or perhaps even a launch tower or space elevator. The idea would be concentrate as much as possible on making space much more of a money making venture than it is now, and use the built-up infrastructure to eventually build the interplanetary craft needed to carry humans further into the solar system.
Asteroids: Somewhat of an underdog compared to the others, its still mentioned occasionally in various sources. Instead of concentrating on 'major' bodies such as the Moon and Mars, emphasis for this strategy is placed on the manned exploration and exploitation of near-Earth asteroids. Technical difficulty would be somewhere between returning to the Moon and sending expeditions to Mars. And with thousands of potential destinations, NASA could be constructively busy for decades.
This strategy has two major potential pluses over the others. First, Asteroids taken in their thousands represent an immense treasure trove of mineral wealth; an estimate of single typical nickel-iron asteroid from a few years ago put the worth of the asteroid's minerals and metals at over $12 trillion.
Second, asteroids can be made mobile using even today's technology. It would be a very slow and gradual process, but valuable asteroids can be 'herded' closer to Earth, inserted either into an L4 or L5 Lagrange point or into Lunar orbit, where they can be much more easily studied and harvested. Hollowed asteroids also offer ready-made armor against radiation and impact hazards in space, and small, properly hollowed and modified asteroids could serve as the chasis fo interplanetary craft.
Which strategy would be best? That would depend on the goals people wanted to accomplish. All have advantages that could benefit not juts the US, but the world beyond as well. However, if we want to see any of these objectives succeed in our lifetimes, we have to pick one and stick with it.