I'm curious, the article stated that it will reach GS orbit in the next three months or so. Do you put it in orbit at a faster speed than req'd and let it drift (or steer it) to a pre-determined altitude, and then sync the speed/ orbit? Lots of space junk whizzing about!
The rocket put it into an orbit that is highly elliptical, with a perigee of about 120 miles and an apogee of about 26000 miles (a little higher than geosynchronous). What is supposed happen is that we do three maneuvers with the spacecraft 100 lb thrust engine to boost the perigee up to about 11,000 miles. It is still pretty highly inclined and still elliptical. Then we use on-board ion engines (Hall Current Thrusters) with a thrust of about 1/2 ounce and then thrust for many hours a rev, or multiple revs, pointing the spacecraft in the right direction to take out the inclination, raise perigee, lower apogee, and then stop in geosynchronous at the right spot. The best direction to thrust is continually changing and determining that on a second-to-second basis is a pretty tricky problem. The acceleration is low (spacecraft weights a little less than 14000 lbs right now, and you are pushing it with around 1 once of thrust) so that's what takes the 3 months.
What happened on the first one is that the 100 lb engine failed after about 13 second of total run time (instead of the intended 3 and a half hours). We used some 5 lb thrust chemical thrusters until we used up most of the fuel for that (saving enough for the on-orbit mission of wheel desaturation), then the ion engines for the next year and 2 months in the most optimal way possible, and got it to orbit. We won an Aviation Week laureate award for saving the mission. It launched in August 2010 and got there in October 2011.
We are pretty sure the 100 lber is going to work this time, and we will find out in about 8 hours. That's why I am in Colorado Springs right now. I am the lead engineer for the attitude control subsystem which is what determines where the spacecraft it pointed, drives the attitude to the desired direction, and fires the engines (100 lber, 5 lbers .2 lbers and ion engine and associated gimbals). I am here to make sure that it is working correctly and determine that if it isn't, what we should do.
We do have to concern ourselves about space junk and space "no junk" like the Space Station. Particularly now, when the perigee is down in the upper atmosphere - so close we have to select the thrusters for attitude control because the aerodynamic forces are too high to handle with the reaction wheels. There is a whole lot of stuff (junk and otherwise) in low Earth orbit. After the first 100-lb engine burn the perigee is high enough that we aren't close to very much in the way of junk at the low side. On the high side we are going through geosynchronous altitude but at an inclination that means there's not a lot to worry about there, either. So while there are guys who figure out the close approaches and adjust the maneuvers to avoid close-misses, it's only a significant problem until the first maneuver, which is a few hours away.
Brett