Hugh Pickens writes:
The cost of getting to orbit is exorbitant, because the rocket, with its multimillion-dollar engines, ends up as trash in the ocean after one launching, something Elon Musk likens to throwing away a [Boeing] 747 jet after a single transcontinental flight. That's why on Tuesday morning at 6:20 a.m. EST his company hopes to upend the economics of space travel in a daring plan by attempting to land the first stage of a Falcon 9 rocket intact on a floating platform, 300 feet long and 170 feet wide in the Atlantic Ocean. SpaceX has attempted similar maneuvers on three earlier Falcon 9 flights, and on the second and third attempts, the rocket slowed to a hover before splashing into the water. “We’ve been able to soft-land the rocket booster in the ocean twice so far,” says Musk. “Unfortunately, it sort of sat there for several seconds, then tipped over and exploded. It’s quite difficult to reuse at that point.”
After the booster falls away and the second stage continues pushing the payload to orbit, its engines will reignite to turn it around and guide it to a spot about 200 miles east of Jacksonville, Florida. Musk puts the chances of success at 50 percent or less but over the dozen or so flights scheduled for this year, “I think it’s quite likely, 80 to 90 percent likely, that one of those flights will be able to land and refly.” SpaceX will offer its own launch webcast on the company's website beginning at 6 a.m. If SpaceX’s gamble succeeds, the company plans to reuse the rocket stage on a later flight. “Reusability is the critical breakthrough needed in rocketry to take things to the next level."
Spacefuel as in hydrogen/oxygen to get past LEO.
Your own link to Wikipedia lists a large number of problems with cryogenic fuels. This is one of reasons why they are not used on long missions - they are very hard to store. A mission to Mars will take about 520 days (if we take Mars-500 as a reference.) You'd have to keep liquid hydrogen in liquid form for all this time, despite heating by the Sun. There is no way to refuel, and there is not enough energy to liquify the gas. Other methods that are listed in the link may or may not be effective. In any case all this infrastructure will cost immense amounts of money, which will not be available because politicians have to deal with stuff on Earth first. And what exactly will the humanity gain from visiting Mars? I'd rather send a thousand robots instead of five bags of salt water. Things will change if robots find an alien spaceship there, for example. But until then there is no point going there in person.