How do conventional rockets work?
Even though DS1 is much smaller than spacecraft designed to carry humans and many satellites already in orbit, it still takes a lot of thrust to put DS1 into orbit. The reason for this is the gravity of Earth. Earth is a very massive object and pulls strongly on everything close to it. In order to reach escape velocity (the speed needed to push something outside of Earth's gravity well), a huge amount of thrust is needed. That is why large multi-stage rockets, like the Delta II or the Saturn V (the Apollo program's launch rocket), are needed to put something into space.
How did DS1 get into space?
Could NASA use ion propulsion to put a ship into space?
What is gravity?
What is thrust?
How does a multi-stage rocket like the Delta II work?
Why is it a good idea to launch a ship into orbit from near the equator?
What is escape velocity?
What's a gravity well?