When an astronaut goes to outer space, what can you measure? I'm thinking about the person's safety, so this is what I got so far:
Is there any other relevant constant that I could measure for safety?
Just kidding: You should be monitoring the amount of water in the astronaut's helmet.
Not just kidding: Modern spacesuits are complex devices. You should be monitoring for signs of problems with the suit. The manufacturer of the spacesuit will have all kinds of fault detection, isolation, and recovery (FDIR) mechanisms built into the suit. You should be monitoring each and every one of these. You should also be paranoid and assume that the FDIR isn't perfect. That means you should be monitoring things such as the CO2 level. You should monitor anything and everything you can think of that might be a sign of a problem.
Consumables are another obvious set of things you are missing. What if the astronaut's metabolism is high? If you aren't monitoring the amount of stored breathing atmosphere you won't know the astronaut will die six hours into a planned eight hour EVA.
Finally, you need to monitor the voice loop. Despite your best efforts to monitor everything, there will inevitably be some things you miss. When the astronaut says "my helmet is filling with water" you need to work feverishly to get that astronaut back inside ASAP.
