Dr Allan McInnes discusses his role in helping NASA design the Mars exploration rovers. He was responsible for ensuring all of the different parts fit together and did their jobs!
Points of interest:
- A number of rovers have been sent to Mars to characterise Martian climate and geology
- Spirit, Opportunity and Curiosity have been the most successful.
DR ALLAN MCINNES
I was working as what’s known as a spacecraft systems engineer. What that means is somebody who’s concerned with the whole spacecraft. A spacecraft is a very complicated system. We have engineers who are dedicated to designing particular parts of it. So for example, we might have a rocket engineer who focuses on the propulsion system, and we’ll have an electrical power engineer that’ll design the solar arrays and things like that. But somebody needs to make sure that all of those pieces fit together properly, and that’s what a systems engineer does. So we’re kind of like the conductor in the orchestra in a way – we’re making sure all the different parts are going to fit together and that the overall satellite will do what it’s supposed to do.
It was sort of a lucky break to be working on the Mars rover. The Aerospace Corporation primarily works with the US Air Force, that’s why they exist, but when we have some spare time, we also do some contracting out to NASA. I got sent up there to do what’s known as failure modes effects and criticality analysis. So failure modes effects and criticality analysis is actually pretty crucial for satellite design. Satellites or rovers, when we put them on Mars, obviously they’re not here anymore, which means if anything goes wrong, it’s very difficult to fix it. So a lot of the time and energy that goes into designing a satellite is making sure that it won’t break or, if it does break, it can recover from it somehow. And the purpose of a failure mode analysis is to essentially sit down, go through the entire system and say what would happen if this piece broke? What would the effects of that thing not working be and then do we have any kind of backup plan?
So for example we might look at what would happen if this part of the computer stops working – does the whole mission come to an end or is there a backup computer that can take over? And usually we’d try to figure out if there was a way to recover, you know, maybe we’d add a radio or something like that if it was a communication system that had failed. Was there something else we could use to talk to the Earth so the mission can have a fairly high chance of success?
How did I end up going from the Aerospace Corporation to the University of Canterbury? In a sense, I’ve sort of come full circle here. Despite the accent, I am a New Zealander. I did my undergraduate degree here at Canterbury in electrical engineering, and then I graduated and went off to the United States and ended up studying over there at a university. From there, I ended up with a job at the Aerospace Corporation and then eventually started to think it might be nice to come home, and then a job came up at the university here. I had really good memories of undergraduate here and just how great the department was and thought, yeah, I’d like to go back and try that and maybe take some of my experiences and pass them on to the next generation of engineers.