"A trip to the moon on gossamer strings? A "partial" space elevator that could carry satellites to geosynchronous orbit might be just the ticket." This source gives a great insight on how a space elevator would be created an operated. It has great information on much it may cost, how it would be used, and how it could even be possible. This is a reliable source, as National Geographic is a reliable company. I believe this resource could be very useful for our themes and research.

"When discussing the possibility of interstellar travel, there is something called "the giggle factor." Some scientists tend to scoff at the idea of interstellar travel because of the enormous distances that separate the stars." This site goes into great detail about the amount of energy and the level of technology required for interstellar space travel. Michio Kaku describes that many scientists believe that interstellar space travel would be impractical and impossible, considering the massive distance between stars. For instance, traveling at light speed would take you roughly 100,000 years to reach the edge of the Milky Way galaxy. This is a reliable source, considering it was written by Michio Kaku himself.

"The Next Giant Leap For Mankind." This is the website for the 'Mars One' mission. The entire site describes what Mars One is, which makes a very good example of the commercialization of space. Mars One's goal is to not only create a permanent settlement on Mars, but create some kind of reality show on the red planet. Thousands of people have already signed up for this one way trip to another planet, even knowing that they will never come back. This site is reliable because it is run by the Mars One company.

"A solar sail, simply put, is a spacecraft propelled by sunlight. Whereas a conventional rocket is propelled by the thrust produced by its internal engine burn, a solar sail is pushed forward simply by light from the Sun." This site gives great information on how solar sails work and how efficient they are. The text describes how solar sails can accelerate indefinitely. It also mentions how large they generally are. This information can be useful for certain research points and help clarify what a solar sail really is. This site is most likely reliable because websites ending in ".org" are typically reliable. It has very sound research, as well.

"The skeptics among the Old Space people will say to the upstarts: Where's your rocket? How many times have you launched? Can you deliver reliably? Repeatedly? Safely? We put a man on the moon - what have you done?" I find this source to be incredibly useful for it describes how current companies are already at work creating innovations in space travel. It shows how "Old Space" and "New Space" are competing with each other and how NASA is chipping in. I will use this website to learn what we already have and how far we still need to go. I believe this is a reliable source because it was published by The Washington Post, a typically trustworthy website.