Illustration: Blood Bros.

The commercial space business has blossomed over the past decade. Two companies, though, have grabbed the spotlight, emerging as the most ambitious of them all: Blue Origin and SpaceX.

At first glance, these two companies look a lot alike. They are both led by billionaires who became wealthy from the Internet: Jeff Bezos of Blue Origin earned his fortune from Amazon.com, and Elon Musk of SpaceX got rich initially from Web-based businesses, notably PayPal. Both companies are developing large, reusable launch vehicles capable of carrying people and satellites for government and commercial customers. And both are motivated by almost messianic visions of humanity’s future beyond Earth. This coming year, we’ll likely see some major milestones as these two titans continue to jockey for position.

Even further down the road, both Bezos and Musk see their companies truly enabling the expansion of humanity beyond Earth. But they have different visions of where we should go and how.