It's totally possible, but not a good idea. You'd need to buy a new handlebar, shifter/brake levers, front derailleur, stem, and brakes. The cheapest way to do it would be to get bar end shifters and Dia-compe 287-V brake levers. That way you wouldn't have to replace the front derailleur or the brakes. But if you want STI levers (like most modern road bikes) you'd have to replace all of that stuff. And the cost of STI shifter/brake levers is ridiculously high if you buy them separately. My advice? Sell the Astrale and buy an actual road bike (but not a K2, I work at REI and they are pretty poor quality).