The platinum group metals are crucial to electronics, massively expensive, and extremely rare on this planet. But on asteroids? A single one holds billions of pounds of these metals - and that could start the era of private space exploration.
Platinum is the most famously expensive of these metals - it's generally held up in the popular imagination as the one thing that's even more valuable than gold - but the rest of its group is equally rare and valuable. These metals - platinum, ruthenium, rhodium, palladium, osmium, and iridium - are super stable, nearly impervious to chemical attack, and deal well with high temperatures. These qualities make them perfect for use in electronics, but it takes thousands of dollars just to buy a few grams of the stuff.
A big reason they're so rare is that they don't naturally occur on Earth, as they almost exclusively come from sites of asteroid impact. Of course, that opens up a rather interesting possibility - how much of these metals are contained in the asteroids that haven't hit Earth? Surveys of asteroids close to Earth reveal even moderate-sized ones - about 1,500 feet across - have billions of pounds of these metals, far more than we've mined in all of human history. A single asteroid could give us all the platinum group metals we could possibly need for centuries.
So how do we get the stuff? The basic technology is either already available or readily conceivable, and steroid mining has become a serious topic of discussion. Indeed, it could have far-reaching impacts for space exploration as a whole. The quest for super-cheap electronics and mining-based fortunes could spur a rush of private explorers into space in much the same way the lure of gold drove Americans westward in 1849. As crass as it might sound, the chance at some serious profit might be what finally pushes humanity into space once and for all.