Lessons in parenting

Which do you think is harder? Feeding a 7 month old, or docking to the international space station?

You can already guess where I’m going with this, but lets lay out some of the difficulties for each, shall we?

When docking to the ISS, the space shuttle moves to within 50 meters of the station, stops, waits for confirmation, then approaches at a speed of .05 m/s until it gets to within 9 meters of the station, stops again, waits for confirmation, and carefully lines up with a black docking target 30 cm above the docking port. Pilot and copilot have to control 6 degrees of freedom to ensure that the shuttle is aligned perfectly so that the two systems slip and hook together for a proper seal.

An exercise that Nasa recommends for young children to learn and appreciate the complexities of the motion is to tie a string between two kids. In the middle of the string, hang a small weight. Next, place a cup on the floor and instruct the kids to insert the small weight into the cup without using their hands. For added difficulty, blindfold the kids and have them do it listening to instructions from someone else.

In other words, it’s a pretty tricky exercise, and one that you really don’t want to mess up. But, now let’s consider some of the things that make it less difficult.

A couple of things that you have going for you are the masses oaf the shuttle and space station. They’re both really big and have an enormous amount of momentum. The forces the pilot is applying with the navigation thrusters is miniscule in comparison, so you aren’t moving in large steps. The docking area is clear of other modules, to minimize the risk of a collision. There is no gravity, so you aren’t at risk of your cargo spilling if you need to roll over to get a good seal. And finally, you only have to dock once.

Compare this to feeding a seven month old. You still have to control six degrees of freedom, but percentage-wise you are moving a much greater distance, and a lot faster. The dock is prone to sudden, unexpected movements when it gets distracted, occasionally turning away just as the spoon is entering. There are also two appendages that often flail about in the approach path, risking collision with every approach. You do have to deal with gravity, limiting your approach options lest you spill your cargo all over the station, yourself, or the floor. Neither you or the station are very heavy, so you really have to police how much energy you expend. And finally, you have to repeat this procedure many, many times.

It may not come with bragging rights, but there’s not a single mealtime I don’t walk away from feeling like I couldn’t handle being an astronaut.