Yeah right lets take a processor thats slower than 4 year old pcs, an operating system with no memory protection, and a worse web browser than I have on my cell phone and use it for mission critical control applications.
You don't need a lot of processing power for a space shuttle, you need to be able to multi task properly and a web browser is pretty irrelevant. An IBM AP101 could do the job, well 5 of them to be safe, gotta have back-ups.
The biggest problem I've had with my personal space shuttle has not been the computer system anyway. It's been trying to find enough space to store the high-altitude zeppelin I launch it from.
Steam-shuttles, the only way to fly.