Apologies for the supermarket-tabloid-style headline. But ever since Boeing (NYSE: BA) joined with Lockheed Martin (NYSE: LMT) to form the United Launch Alliance, the twin aerospace titans have dominated the race to space here in the U.S. For the time being, they are indeed our "galactic overlords."

And yes, as reported in The Wall Street Journal this week, the Alliance has indeed adopted an "orphan," allying itself with a little-known company by the name of XCOR Aerospace. XCOR aims ultimately to develop a reusable "space plane," with which it will run commercial flights into space for tourists. In the meantime, it's looking to grab some quick cash helping the Alliance build cheaper rocket engines.

The Alliance currently buys engines from fellow corporate giant United Technologies (NYSE: UTX), you see. Some pundits suggest XCOR is little more than a stalking horse -- that the Alliance is only threatening to buy engines from XCOR in hopes of extracting price concessions from UTC. Other competitors exist as well. Alliant Techsystems (NYSE: ATK) has built the engines for rockets Lockheed produced before, making it a probable contender for some of that space-aged moola floating around. The Alliance also has a history of partnering with tiny, no-name shops -- albeit not always successfully. In 2008, it backed a bid by tiny PlanetSpace to win a $3.5 billion NASA contract to run supplies to the International Space Station.

It didn't win, of course. Rather, NASA split the contract between an established space firm, Orbital Sciences (NYSE: ORB), and a newcomer with a superb pedigree, SpaceX, the cosmic concern founded by Tesla CEO Elon Musk.

And that's the real significance of this news. Like XCOR, Musk's SpaceX was once little more than a daydream, you see. But after winning NASA contracts worth nearly $2 billion over the course of just a few short years, the company's starting to look like a credible contender.

So yes, maybe the Alliance is just using XCOR for its own purposes today. But that's the thing with rockets; light a match too close, and they can spark up and quickly elude your grasp. One of these days, the Alliance is going to get too clever for its own good. One day, one of these orphan space stocks may grow up to overthrow the galactic overlords.

What's your favorite space startup? Is it Jeff Bezos' Blue Origin, perhaps? Richard Branson's Virgin Galactic? Or someone else entirely? Tell us about it in the comments section below, then check back to see what other space companies your fellow Fools have spotted.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.