A couple of the astronauts aboard the International Space Station took a walk outside today. Dangerous work. As New York Magazine reports:
An Italian astronaut, Luca Parmitano, nearly drowned during the station’s last spacewalk in July after water began pooling in her helmet.
This time they were outside removing a 780 pound pump. That’s 780 pounds on Earth. In microgravity it hardly has any weight at all.
Please, don’t stop reading now.
Weight doesn’t really matter!
Microgravity makes it easier for the astronauts to move something, but that object still exerts force. Force is important. If your hand gets smashed by a hammer, it’s not the hammer’s weight that does the damage. It’s the force!
A little math coming up, but I’ll explain. Don’t panic.
The formula for force is F = ma, or force equals mass times acceleration. See what’s not there? Weight.
What is there is “mass.” Even in microgravity the pump’s mass is unchanged.
So, this pump that currently won’t register on a scale can smash your bones to bits! And, of course, with microgravity it’s easier to get the pump moving.
The astronauts will be back out in a few days to replace the bad pump with a spare. It’s another spacewalk fraught with peril and danger. Extremely physical work performed by major league nerds.
If you’ve read my blog any length of time you know I’m not a big supporter of the manned space program. However, that doesn’t stop me from appreciating how difficult and dangerous work in orbit is.