You people continue to get it wrong, and I'm always amazed that you continue to get it wrong.
"Earth-to-LEO" orbit is irrelevant. "Halfway there once you're in Earth orbit" is irrelevant. Price-per-person-per-trip to orbit is irrelevant.
Until, and ONLY until, there is a COMPELLING ECONOMIC INCENTIVE FOR CORPORATIONS, SYNDICATES, and WEALTHY--VERY WEALTHY--VENTURE CAPITALISTS to fund such explorations, you ain't goin' NOWHERE.
The death of NASA would be the best thing that could happen to the future of space exploration. The agency ought to be broken up and its military role doled out to the appropriate branches of service.
Then, the government ought to tell the afforementioned mega-big-spenders that if they can figure out a way to get there and bring back the stuff, the gov. will supply SEED MONEY, maybe some rocket boosters, whatever.
Then, let the Invisible Hand take its course, as it inevitably did.
Where do I get this idea? Simple. From HISTORY.
Best Example: We tend to think of Columbus as having "discovered" America. Of course we all know he wasn't the first non-"Native American" to get there. But he is credited with it because HIS was the expedition that mattered.
How did he come to make the voyage? Again, it's simple: Greed, a.k.a. Adam Smith and "The Wealth of Nations" and all that jive.
You see, people who knew anything knew the world was round, of course, they had known it since Greek Antiquity. But they didn't realize it was as BIG as it turned out to be (even though Euclid estimated the true circumference of the Earth to a pretty good degree of accuracy).
They thought that all those reports of sightings of land on the other side of the Atlantic were of the EASTERN coastline of Asia. And Asia was a HOT, HOT market just then, because of the Spice trade. The Italian city states, particularly Genoa and Venice, had a monopoly on the overland spice routs to the Orient, and they sold their precious spices, which European cookery had decided it could not do without once tried, at a VERY hefty price.
So Spain, feeling left out, and desiring to make a splash now that they were solidly back in the mainstream of Christian Europe with the expulsion of the Moors, wanted to find an alternate route to the centers of spice production.
So in reality that was what Columbus was after: An alternate route to "the Indies", to "Cathay" and to the fabulous--and lucrative--Orient.
Cutting to the chase, we all know that they didn't get what they were after. But of course, they also got wealth of another kind in terms of precious metals and interesting crops and other foodstuffs, far in excess of what the Spice Trade would have meant.
Within a few years Spain became a European--and the first WORLD--power, whose hegemony would last, even counting its declining years, for almost four hundred years.
If you will do some checking, you will learn that no significant exploration of the unknown has ever occurred JUST "to see what was there." There was ALWAYS an economic incentive that served as the catalyst.
So, until you space-nerds figure out how to bring a SIGNIFICANT economic incentive into play, no one in the world is EVER going anywhere in space, because it will always be a case of a venture that CONSUMES capital rather than creates it.
Off the soap-box, now.
... New propulsion technologies are the key to interstellar travel. In order to perform meaningful exlporation beyond our solar system, we need radical new means of propulsion. Right now, we can barely travel in space at tiny fractions of 1% of the speed of light. Roundtrips to and from the nearest stars will take many hundreds of years. At that rate, everyone on earth who would care would be dead before a mission returned. Even at the speed of light, the nearest stars are years away, let alone other galaxies.
In essence, mankind is completely stranded on Earth (or at least in our solar sytem), until we can travel at many times the speed of light, without high energy (i.e. fuel, weight) costs. This will require a completely new physics.
The cost of ths effort is currently very small. I see keep at it - if we really want to explore beyond planet Earth.
[Suppose human history had been different and we had invented/discovered electricity and other forms of energy before combustion. The invention of combustion--chemical sources--would have been heralded as the greatest advance ever! A pre-combustion, pre-chemical world would have no aircraft (i.e., commercial airliners, jet fighters), no mechanical transportation, etc. But trains run on electricity! someone shouts. Yes, and where does the electricity come from?...]
Which is why battery-powered cars are jokes, unless "assisted" with a gas engine.
Which is why electric rockets have millinewtons of thrust.
A rough rule-of-thumb is that it takes about 20 kilowatts to generate one pound of thrust. Do the calculation for the Space shuttle; each SSME engine is putting out something like six megawatts and weighs only 7000 lb. The solids are even better in specific power.
The key to the solar system could be the nuclear thermal rocket. It alone has both high thrust (meaning short trip times) and good performance (Isp ~900 seconds). A Nuclear Light Bulb would be even better. Not in my lifetime, I'm afraid.
I told my boss: "If we were really serious about busting up the gravity well and getting off the planet, we would stop developing rockets [I'm a rocket guy]. We'd use the ones we have, and put all of our resources into building a space elevator (see Clarke's Fountains of Paradise or Hogan's Web Between the Worlds)."
People easily and glibly talk about "fields", electromagnetic phenomena, antigravity. Show me one that works and gives more than a mouse fart in terms of thrust.
A few years ago, NASA's Lewis Research Center found that it had a spare $50K at the end of the fiscal year. They used it to announce a contest: Fifty grand for the first truly new propulsion system that also worked.
They got lots of entries. Some were truly new and didn't work; some worked and were not truly new.
The prize was never awarded to anyone.
As I remarked to Marc Millis (NASA's "Breakthrough Propulsion" guy), "If these schemes were feasible, the extraterrestrials would have reduced them to practise millennia ago. We would observe their traffic. Hence none of these schemes are feasible--or we are alone." A variant of the Fermi Paradox, I know.
He was unable to form an intelligible response at the time.
--Boris
It turns out that one gee (1 g) is 1.03 light-years per year**2.
You accelerate at one gee for a year and (ignoring Einstein) you will be up near "c" and about 1/2 lightyear from Sol.
Consider a kilogram so accelerated. Its kinetic energy (classically, not relativistically) is 4.89x10**17 joules. A year is roughly pi times ten to the seventh power seconds. Hence the propulsive power that must be applied to the kilogram for a year is about 1500 megawatts. Call it two San Onofre nuclear power plants running full-tilt for a year. If our kilogram is going to have a useful payload and structure (i.e., non propulsion elements) the propulsion system must weigh much less than a kilogram. I'll give you 100 grams and 100 cubic centimeters. So the problem of interstellar flight is reduced to the problem of condensing two giant nuclear generating stations in to a volume of roughly a handful of sugar cubes. Scale up as needed until you get the "Enterprise".
The problem is that humans are too puny to deal in the sorts of energies we need. Sometimes I think of the problem like this: compress the Sun into an average sized office building and harness its power.
I have some questions I'm saving up for the Almighty:
1. Why did You put everything so bleeping far apart?
2. Why did You make us so short lived?
Looking at the way the universe is designed, it almost seems to have been deliberately arranged to prevent interstellar travel and interactions between (presumed) intelligent species...
--Boris
Present schemes for space profit envision 20 to 30 year payoff periods.
Any project built at 10k per KG wouldn't be able to compete against one built at say, 1k per kg.
An intra-solar nuclear rocket is an all-around good idea.