Out of the companies NASA picked to provide ISS resupply missions back in 2016, Sierra Nevada's vessel is the only aircraft-like design of the bunch -- the Orbital ATK and SpaceX offerings are capsules. That should give it an edge when it carries scientific experiments, as it can land on a runway and offload equipment immediately (crucial for time-sensitive science) instead of waiting for a recovery. There's a pressurized cabin for human-tended experiments.

Dream Chaser might not serve its original purpose for long when the ISS isn't poised to receive funding past 2024. Even so, it should help usher in the private spaceflight era and offer some fresh competition.