A Vision for the Near Future
Obama's decision not to return to the Moon has been rejected. Ignoring the Moon because "we've been there, done that" is simply absurd when there is so much we can learn by being there. Other entities (China for one) are planning their own lunar base and space stations...and it is highly likely that some entity will militarize those platforms. Don't believe that a "treaty" prevents someone from militarization of space - once an entity can establish itself there isn't much anyone else can do to make them compliant.
Since the launch of Sputnik only the old Soviet Union and the United States of America developed the the technology to get into and survive in space. Of course both sides worked with (and paid for) commercial or state partners. Multinational operations began with the International Space Station (ISS). Currently a new international partnership is underway called DEEP SPACE GATEWAY.
Todays space technology requires massive rockets to launch from the surface of the Earth with enough power to escape Earth's gravity to go beyond low earth orbit (LEO). Propellant is required to break the spacecraft acceleration, place it in any kind of orbit, keep the orbit, perform operations, break orbit and head back for a direct hit on Earth. At the end of the mission very little is left of the original launch craft.
Our labs are exploring new propulstion technologies, creation of energy fields, energy containment and more. We have people like Bigelow leading the way with expandables. We have commercial entities working on returning our astronauts into Low Earth Orbit (LEO) and developing the capability of taking them beyond. All of these certainly takes funding but the core technology exists and has been made available to commercial entities at virtually no cost.
Our Apollo space program showed we could safely mate components in Earth orbit before pressing on to the Moon. We can still do this but there will be a time that the orbital junkyard becomes a real threat to anything below and passing through it. Cleaning up this junkyard is going to take time and it's going to take new technology.
I like what the corporate sector has accomplished and where it's going...I have not been thrilled by the increasing timelines.
I WANT TO GO TO MARS. I want to stand on the surface of that planet and go below its surface. Frankly a manned flight just to orbit Mars would be hazardous considering the current hardware configuration. Orion would require an additional module to allow some "breathing room" for the astronauts. Lets learn what we need to know by returning to the Moon.
(Updated Jan 2020)