Today, I finally did what I had been avoiding all week - which is finally forcing myself to internalize all these bits and pieces I've been learning about rendezvous into one clear collected vision.

I don't talk about the technical details of my work too much, mostly because I think it would bore people (and by people, I mean my mother, who is pretty much the only non-space program-affiliated daily reader of my blog). Today, I'm just inspired.

Rendezvous, in space, is just like a romance. The space station is flying around in orbit, lonely, and in need of supplies and company. So we launch another spacecraft, the orbiter to go meet it. Rendezvous is particularly difficult for me (both romantically and technically, as it turns out). This is mostly because I find the flight path of a rendezvous completely non-intuitive. Its not like entry and landing, where the flight path is "down" or launch, where the flight path is "up and over." Those things make sense. They probably even make sense to you, mom.

So, picture the earth (man, that is a sweet earth!). Now, picture the space station traveling around the earth in a nice little circle (like a hula-hoop). Its whipping around at about 20,000 miles per hour. It actually circles the Earth every 1.5 hours. Its only about 200 miles above the ground (roughly the distance from Houston to Dallas). Now, picture your space shuttle, sitting on the ground in Florida.

Somehow, you need to take the space shuttle, that is sitting pretty still at the Cape, launch it into the exact spot it needs to be at so it can effectively collide with the space station that is flying around and around the earth. Now, your first impulse would be to think: missile! and just wait until the space station passes right over head the launch pad and just aim the space shuttle at it and fire.

That would be easy to understand.

But we don't do that (for some very good reasons).

Instead, we wait until the space station passes over the launch pad. And then we launch the space shuttle behind it AND below it. Meaning, if the space station is at 200 miles above the ground, the space shuttle may only be at 100 miles above the ground.

There are some tricks to flying in space that don't make sense here on earth:

1. The higher something is in orbit, the slower it goes. Its the physics of gravity.

2. If you hit the gas pedal on your car here on Earth, you just go faster. If you were to put that same car in orbit, strap a rocket on the back of it, and hit the gas, you would go higher. But since its higher (see rule number one) its slower.

So, way up where the space station is, its going at 20,000 miles an hour. But the space shuttle at the lower altitude is going even faster. Since we launched the orbiter behind the space station, its catching up. Rendezvous is carefully timed so we don't "lap" the space station and go flying right by it. So, we plan a series of rocket firings to climb up to the space station's altitude at just the right time for when we catch up with it.

Now, to make matters even more interesting, its hard for us to know exactly where the space shuttle and space station are! Oh, we have a pretty good idea, no question. But at 20,000 mph, little differences become big. Say you're driving a car at 75 miles per hour and you're trying to hit another car also driving at 75 miles an hour. At first you see your target maybe a mile in the distance, so you turn your car and aim at it. But then, you have to put a blindfold on and just trust that you'll stay pointing the right way, even though a little bump of your steering wheel could make you end up way off course. Can't you see how easy it would be to miss?

So, this is what I'm contemplating today - how carefully choreographed everything is in order to make two spacecraft arrive in the exact same time and place in the vastness of space.