The most sophisticated satellites can cost more than $1 billion to build and launch. Yet all that money and technology hasn't been able to buy something every car owner takes for granted: on-demand repairs and tune-ups.

Now, thanks to years of development by governments and private companies, outer space satellite servicing is becoming a reality — and a business.

Just recently, the U.S. Defense Advanced Research Projects Agency, or DARPA, announced that a robotic repair arm it developed will be ready for launch in 2025. By then, it will be just the latest advance in satellite tune-ups, ready to help clear a path through the growing accumulation of space junk orbiting the earth.